[HN Gopher] Earth-like planet spotted orbiting Sun's closest star
       ___________________________________________________________________
        
       Earth-like planet spotted orbiting Sun's closest star
        
       Author : rntn
       Score  : 210 points
       Date   : 2022-02-11 08:04 UTC (14 hours ago)
        
 (HTM) web link (www.nature.com)
 (TXT) w3m dump (www.nature.com)
        
       | lbriner wrote:
       | We can't even work out how to run our own planet in a consistent
       | and consensual way, I say leave it to the other more civil aliens
       | to inhabit, otherwise we'll end up with another broken planet.
        
         | NittLion78 wrote:
         | This is basically the entire plot of Sid Meier's Alpha
         | Centauri.
        
         | sva_ wrote:
         | I don't think space is so crowded and we got enough empty rocks
         | up there.
        
         | WithinReason wrote:
         | What is there to break on a lifeless planet?
        
           | brabel wrote:
           | Whether there's life on this planet is not known, it's in the
           | inhabitable zone so that possibility cannot be discarded.
        
           | lbriner wrote:
           | Clearly the implication is that it is another habitable
           | planet and the other comments talking about going there etc.
           | It isn't the rock I am worried about, it would be community
           | that decides to move there and then starts exploiting each
           | other leaving a planet depleted of resources and a rather
           | long journey home!
        
       | raxxorrax wrote:
       | That is pretty exciting. Some say life would be difficult because
       | Proxima Centauri is a flare star, which has violent outbursts of
       | radiation. Not more than the sun though, even if it is so much
       | smaller. But the habitable zone would also be much closer to the
       | star.
       | 
       | It has a significant life span of about 4 trillion years and
       | could easily outlive the present universe several times.
        
       | j0057 wrote:
       | If there are three known planets in the Proxima Centauri, why are
       | they called b, c and d -- why is there no Proxima Centauri a?
        
       | 1970-01-01 wrote:
       | Hey, we also got a weird signal from this area not too long ago!
       | 
       | https://en.wikipedia.org/wiki/BLC1
        
       | T-A wrote:
       | There seems to be some confusion about the meaning of "within the
       | habitable zone".
       | 
       | From the paper (Introduction and Conclusions, respectively) [1]:
       | 
       |  _The habitability conditions of Proxima b, which orbits within
       | the HZ of the star, have been extensively studied (e.g. Barnes et
       | al. 2017; Ribas et al. 2016; Turbet et al. 2016; Meadows & Barnes
       | 2018). On the other hand, the candidate Proxima d orbits much
       | closer to the star and outside the HZ range._
       | 
       |  _In particular, the discovery of an Earth-mass planet orbiting
       | Proxima Centauri (Anglada-Escude et al. 2016), our closest
       | stellar neighbour, was one of the most significant results in the
       | field, in part because the planet orbits inside the habitable
       | zone (HZ) of the star (e.g. Kopparapu et al. 2013)._
       | 
       | So, Proxima d is too close to the star to be _inside_ the HZ; it
       | 's _within_ the HZ in the sense that the HZ is further out from
       | the star.
       | 
       | The author of the Nature commentary, which claims that "it could
       | have oceans of liquid water that can potentially harbour life",
       | apparently didn't read the paper.
       | 
       | [1]
       | https://www.eso.org/public/archives/releases/sciencepapers/e...
        
         | ethbr0 wrote:
         | Here's a good collection of details about the entire star
         | system of Proxima Centauri, including its planets.
         | 
         | https://www.star-facts.com/proxima-centauri/
         | 
         | Also fascinating, a relative distance vs time graph of close
         | stars. It turns out we'll have closer distances for 6 in the
         | next 10,000 - 50,000 years.
         | 
         | https://www.star-facts.com/wp-content/uploads/2020/08/Neares...
         | 
         | Somehow I feel like Elon Musk has a print out of that graph on
         | his office wall.
        
           | akamoonknight wrote:
           | Making an assumption here about Proxima Centauri's own Oort
           | Cloud, but seems like if it's the same size as ours, they'd
           | overlap? Seems like a potentially interesting way for "stuff"
           | to get transferred from one solar system to another.
        
             | jl6 wrote:
             | I believe we are discovering that space isn't as empty as
             | we once imagined. Rock-hopping could be a viable method of
             | (slow) interstellar travel.
        
               | oAlbe wrote:
               | Isn't that how you end up in an endless Solar System war?
               | 
               |  _Belta-lowda! Belta-lowda! Belta-lowda!_
        
               | ncmncm wrote:
               | If you take long enough at it, you get comfortable out
               | there and don't need stars anymore.
        
               | JohnWhigham wrote:
               | Eh, we're talking about a section of an arm on a galaxy
               | that we're in. I'm pretty sure there's _nothing_ in
               | between most galaxies.
        
               | floxy wrote:
               | https://en.wikipedia.org/wiki/Intergalactic_star#Mass
        
           | irrational wrote:
           | I only counted 5 (including Proxima Centauri). What are the
           | six that you see?
        
             | LeifCarrotson wrote:
             | Barnards Star, Lalande 21185, then Alpha Centauri, then
             | Proxima Centauri, then Ross 248, then Gliese 445 makes 6.
             | 
             | There are 6 if you count Proxima Centauri and Alpha
             | Centauri separately; 7 if you count both stars in the Alpha
             | Centauri pair separately, and 5 if you count Alpha and
             | Proxima Centauri separately.
             | 
             | Alpha Centauri is the binary system of Alpha Centauri A and
             | Alpha Centauri B, which are separated by about 10-30 AU.
             | It's very, very close in terms of interstellar distances to
             | Proxima Centauri, which is a red dwarf that orbits Alpha
             | Centauri A and B at a distance of 13000 AU, or 0.2 LY - a
             | remote enough orbit that it makes sense to keep track of
             | whether it's on the near side or far side of the triple-
             | star system.
        
               | ruffrey wrote:
               | For reference, Saturn is about 9-10 AU from the Sun.
        
             | [deleted]
        
           | kibwen wrote:
           | _" Unlike the Sun, which will evolve into a red giant in 6.5
           | billion years and reach the end of its life at an age of
           | about 10 billion years, Proxima will stay on the main
           | sequence for another four trillion years due to its low mass
           | and low energy production."_
           | 
           | They laughed at me when I bought investment property on
           | Proxima Centauri b, but who'll be the one laughing in
           | 10.000000001 billion years?
        
             | divbzero wrote:
             | _"Stars with a mass of less than 0.25 solar masses do not
             | evolve into red giants.... Toward the end of the blue dwarf
             | phase, Proxima will become considerably more luminous,
             | reaching up to 2.5% of the Sun's luminosity. Once it runs
             | out of hydrogen fuel, it will evolve into a white dwarf,
             | skipping the red giant phase, and gradually lose all its
             | heat energy."_
             | 
             | So we just need to tackle climate change and learn to live
             | sustainably on Earth, then we'll have a few billion years
             | to figure out how to get to Proxima Centauri.
        
               | prox wrote:
               | A good place to learn how to reverse entropy.
        
             | ethbr0 wrote:
             | I thought that was interesting. Especially when the next
             | news article I read called it a "dying star" (presumably
             | their literary license on red dwarf). Everything's
             | relative!
        
         | BeefWellington wrote:
         | There's also the consideration of the host star to take into
         | account.
         | 
         | I dislike the term "Earth-like" in these publications because
         | it conjures images of a strange alien world able to support
         | (human) life. Even assuming there were life capable of
         | withstanding the constant flares from the host star, I suspect
         | it would have to look very different in color and likely
         | composition to the plant life here due to needing to capture a
         | different part of the spectrum.
        
           | samatman wrote:
           | My education was in chemistry, I've wondered about this topic
           | before. Visible light is actually special after removing the
           | happenstance of DNA-based visual systems from the picture: IR
           | tends to twist or translate bonds (warming) and UV tends to
           | ionize.
           | 
           | Visible light being right in the middle is the trick which
           | gives us photosynthesis, and sight, because in both cases a
           | photon can be captured by a photosensitive bond. It's harder
           | to come up with plausible photosensitive bonds for IR light,
           | and most anything is photosensitive once you get far enough
           | into UV.
        
             | ncmncm wrote:
             | There is a strong selection bias at work: molecules made
             | and operated on by living systems are chosen according to
             | available energy.
             | 
             | A world evolved under lower energies and temperatures would
             | select chemicals with weaker bonds. Other worlds evolved
             | under higher energies and temperatures would select
             | chemicals with stronger bonds.
             | 
             | Visible light is visible to us because it is important for
             | molecules we use.
             | 
             | This is not to say that all points on the energy continuum
             | are equally favorable to potential metabolic processes, but
             | life adapts to conditions, even where they are not optimal.
             | I don't know of any reason to assume the regime where Earth
             | life has landed is optimal, but it has proven more than
             | adequate.
        
             | JumpCrisscross wrote:
             | > _IR tends to twist or translate bonds (warming)_
             | 
             | Is this unique to IR?
        
               | samatman wrote:
               | It's almost definitional of IR in fact, but not quite.
               | 
               | Waves which are relaxed enough to pass through ordinary
               | matter, but interact in interesting ways with metals and
               | other electron clouds, we call radio. Microwaves start
               | out doing this: usefully, they spin water molecules
               | around, hence microwave ovens. What we call microwaves
               | 'bottom out' on not doing so, it's a useful but somewhat
               | artificial category which I would split between radio and
               | IR if you gave me the gavel.
               | 
               | Unlike visible, which is 'visible' because it has
               | distinct properties.
        
         | avsteele wrote:
         | Good catch
         | 
         | "With the small stellar radius, Proxima d ... equilibrium
         | temperature may reach 360K,"
         | 
         | NB: Earth's is 255K. Venus 260K, Mars 215K. So this doesn't
         | tell the whole story, but is probably quite hot.
        
           | ncmncm wrote:
           | It is certainly tidally locked.
           | 
           | So it has a hot side, a cold side, and an intermediate ring
           | at the terminator.
           | 
           | Probably not very comfortable.
        
             | slim wrote:
             | hmm seems like a good candidate for paradise/hell /s
        
             | ErikCorry wrote:
             | Why is it certainly tidally locked when Mercury is not?
        
               | ncmncm wrote:
               | Mercury orbits in 88 days. This other place orbits in 5
               | days.
               | 
               | And Mercury is _almost_ tidally locked. Venus will be,
               | before long.
        
               | ErikCorry wrote:
               | Thx
        
               | jrumbut wrote:
               | For us kids at the back of the class, how are those two
               | facts related?
               | 
               | Why couldn't something orbit the star fast without being
               | tidally locked?
        
             | [deleted]
        
       | PicassoCTs wrote:
       | https://en.wikipedia.org/wiki/Breakthrough_Starshot
       | 
       | Quite a nice concept - accelerate the probe with lasers- no plans
       | for deceleration though
        
       | parksy wrote:
       | Sweet let's crank up the generation ships. Of course picking a
       | suitably inspiring name should be the first priority. Unity?
       | Terra Nova? Gaia?
       | 
       | On a more serious note is this a good candidate for JWST, would
       | it be able to infer chemical composition from the planet's
       | spectrum or something?
       | 
       | Awesome though we went from (in my lifetime) learning at school
       | that other planets have never been observed, to finding them
       | sprinkled around basically every star just like our own. I feel
       | like it won't be long before we detect the first potential
       | chemical markers of alien life, if it's out there. Keep doing
       | your thing space science folk!
        
         | thanatos519 wrote:
         | Generation ships will take some time to get ready. We can
         | railgun tardigrades and aphanizomenon flos-aquae there this
         | year and let evolution do the rest. By the time we (or, more
         | likely, the descendants of cockroaches) get there, it will be
         | teeming with DNA-based life.
        
           | mrweasel wrote:
           | We should perhaps be extra sure that there isn't life there
           | already, before starting to attack a distant planet with
           | terraforming weaponry.
        
             | bluGill wrote:
             | Why bother, even if there is no life there now that doesn't
             | mean their won't be when we finally arrive. Or contrary if
             | there is life there now that doesn't mean it will survive
             | until we get there.
             | 
             | The odds that there is life on our generational ship when
             | we arrive are not that great either.
        
               | YeGoblynQueenne wrote:
               | I seem to remember in an Iain M. Banks novel that there
               | was some controversy about terraforming, like there was
               | an other civilisation that considered it an atrocity and
               | hated The Culture fot that?
        
         | ceejayoz wrote:
         | > Of course picking a suitably inspiring name should be the
         | first priority. Unity? Terra Nova? Gaia?
         | 
         | It'll be Spacey McSpaceface if we put it to a vote.
        
         | EarlKing wrote:
         | Before anyone gets too excited I'd just point out that all they
         | have found is a rocky world within Proxima's habitable zone.
         | That doesn't mean that world necessarily has a breathable
         | atmosphere, water, sufficient gravity, a geomagnetic field,
         | rotation sufficient to distribute heat equitably across its
         | surface (as opposed to it being tidally locked facing Proxima),
         | or any of a dozen other features requisite to support life.
         | 
         | Oh... and did I mention that Proxima is a known flare star?
         | 
         | Wake me up when they find a terrestrial world in the habitable
         | zone of Alpha Centauri instead.
        
           | parksy wrote:
           | Yeah I was being a little tongue in cheek with the
           | excitement, still it's pretty crazy we're actually seeing and
           | cataloguing exoplanets now which was still in the realms of
           | science fiction less than half a century ago.
           | 
           | Anyway if Stellaris has taught me anything it's that the
           | flares will add additional energy credits to the system...
           | what's not to like?
        
           | bbarnett wrote:
           | Easier to add water to Mars, or fix Venus, all possible to
           | have well underway by end of century.
        
         | YeGoblynQueenne wrote:
         | >> Sweet let's crank up the generation ships. Of course picking
         | a suitably inspiring name should be the first priority. Unity?
         | Terra Nova? Gaia?
         | 
         | Titanic. Moribund. Lethe. Purgatory I-X. etc.
        
         | udbhavs wrote:
         | Unrelated but I keep reading that abbreviation as Json Web
         | Space Token
        
           | parksy wrote:
           | Now the seed is planted, one of us is going to talk about
           | JSON Webb Telescopes in a development meeting.
        
         | echelon wrote:
         | It would be even more exciting if we detect _industrial
         | processes_.
        
       | paunthony wrote:
       | Now, we need to have some advanced technologies to have a shot at
       | going there.
        
       | irrational wrote:
       | > Unlike the Sun, which will evolve into a red giant in 6.5
       | billion years and reach the end of its life at an age of about 10
       | billion years, Proxima will stay on the main sequence for another
       | four trillion years due to its low mass and low energy
       | production.
       | 
       | 4 trillion years. Wow. If there was life on one of the planets,
       | it would have a long time to evolve.
        
       | jmartrican wrote:
       | ROAD TRIP!!!
        
       | cletus wrote:
       | Other commenters (rightly) pointed out this is a stretch to the
       | term "habitable".
       | 
       | What's becoming clear though is the only thing stopping us from
       | lots of Earth-mass planets is the abilities of our detectors to
       | detect ever-smaller gravitational wobbles and ever-smaller
       | transits. Bear in mind we only tend to find planets around stars
       | where we're on their ecliptic planes.
       | 
       | So planets seem to be really common. If they weren't the odds of
       | finding planetary systems on our nearest stellar neighbour would
       | be quite low.
       | 
       | But the distances are still so vast that the energy expenditure
       | and timelines are completely impractical (if you assume the speed
       | of light of a hard cosmic limit, which I do).
       | 
       | So if planets are common and interstellar travel is impractical,
       | the only way to expand really is around your own star. This is
       | the Dyson Swarm. This would actually solve the energy issue of
       | interstellar travel (ie"stellar highways") so it's almost a
       | prerequisite. Thing is, Dyson Swarms are likely detectable from
       | vast distances due to their IR emissions (ie the only way to get
       | rid of heat is to radiate it into space and that has a specific
       | frequency depending on the temperature of the radiating object).
       | 
       | But if planets are really common and we don't see any Dyson
       | Swarms it seems that spacefaring life is extremely rare and the
       | most likely number of such civilizations in the Milky Way is 1
       | including us.
        
         | koheripbal wrote:
         | There is a major logical flaw in your argument.
         | 
         | Space travel is only considered to be impractical _for humans_
         | , or similarly large organic entities within their limited
         | lifespan.
         | 
         | The time constraint and the mass constraint may not be
         | particularly relevant to intelligence that no longer has
         | organic form.
         | 
         | An artificial lifeform may not have a defined life span and
         | thus taking 100,000 years to travel the stars may be
         | acceptable.
         | 
         | Additionally, they may only need to make the trip once to
         | establish the receiving antenna, in order to transmit their
         | "progeny" around the galaxy.
         | 
         | Tldr; We are like ants thinking that we need to figure out how
         | to make really long tunnels to cross the Atlantic, instead of
         | focusing on the limitations of our physical bodies.
        
           | bgroat wrote:
           | I'm reminded of the wonderful book "Blindsight" which
           | features vampire astronauts because they can put themselves
           | into states of suspended animation
        
           | bluGill wrote:
           | Time is still a problem because how do you keep such a
           | spacecraft in good repair?. If anything breaks it needs a
           | fair amount of intelligence to fix. same for parts that wear
           | out.
           | 
           | Rocks though space, but that doesn't help learn much. Rocks
           | bring up the other issue is we don't know how many high
           | velocity things might be between starts, numbers below the
           | noise limits of our current sensors is enough to destroy
           | anything we could send out.
        
             | tiborsaas wrote:
             | Your body breaks constantly in minor ways, yet it's
             | automagically repaired to a degree. This evolved naturally,
             | but after sufficient breakthroughs in material sciences we
             | could evolve/design materials that are indestructible.
             | 
             | If you haven't already, give Rendezvous with Rama a read.
        
         | adflux wrote:
         | I will start off by saying I have very little knowledge of
         | physics or astronomy, but reading comments like these feels
         | like I'm watching a 13th century British sailor confidently
         | state what's on the other side of the Atlantic ocean...
         | 
         | Do we really know enough to be able to say if a planet is
         | habitable? Or could there be other forms of life that we don't
         | know of yet... We have only recently put a man on the moon, and
         | now we're saying we would be able to detect dyson spheres...?
        
           | wizzwizz4 wrote:
           | > _We have only recently put a man on the moon, and now we
           | 're saying we would be able to detect dyson spheres...?_
           | 
           | A moth doesn't even have electricity, but it can detect a
           | lampshade. A Dyson sphere is basically a stellar lampshade;
           | we can detect it if the laws of thermodynamics hold, and
           | we're pretty sure they do. (A Dyson swarm is similar, though
           | a bit harder to detect.)
        
             | mcbits wrote:
             | Maybe stars _are_ the Dyson spheres, and their emissions
             | are the waste energy that wasn 't worth harvesting.
        
           | cletus wrote:
           | People bring this up a lot. It's fair to ask. I do often find
           | it comes from a place of wishful thinking. I mean I'd like to
           | have FTL at my disposal true. But what we're dealing with now
           | _seem_ to be either hard physical limits or such close
           | approximations to be effectively the same. The key two are:
           | 
           | 1. The speed of light is a hard limit; and
           | 
           | 2. Thermodynamics (particularly the Second Law) applies.
           | Specifically, you can't get energy from nothing.
           | 
           | From this you can draw a few conclusions:
           | 
           | 1. The likely sources of future energy are solar (most likely
           | IMHO) and nuclear fusion. I hope fusion is viable. I'm not
           | yet convinced it is. More exotic far-future options include
           | antimatter and black holes. Antimatter is something you'd
           | make. Think of it like a battery. So you still need the
           | energy to make it. Black holes as propulsion are the same
           | way. Generating power around a large black hole is
           | theoretically possible but has a bunch of issues;
           | 
           | 2. Reaction mass is a huge problem for traveling large
           | distances, so much so that using photos to impart momentum
           | _seems_ the most practical. Fusion could be viable here.
           | Antimatter and black hole propulsion are theoretically
           | possible;
           | 
           | 3. Because of energy demands, capturing the Sun's energy
           | makes the most sense and doesn't require any "magical" or
           | exotic science or technology;
           | 
           | 4. Because of thermodynamics, eventually heat will radiate
           | into space. It's really the only way of dissipating heat,
           | ultimately.
           | 
           | 5. Like I said, the IR signature is purely a function of
           | temperature; and
           | 
           | 6. A star with a Dyson Swarm will have a very strange (to us)
           | spectrum. Very little visible light. High amounts of IR.
           | There is really no hiding such a megastructure.
           | 
           | So this is essentially a natural conclusion based on physical
           | laws we have no evidence for that they're false or
           | meaningfully incomplete. Thing is, if the speed of light
           | isn't a hard limit that actually makes it _more_ likely we 'd
           | find spacefaring life not less because the reach of such a
           | civilization would be so much farther.
        
           | Loughla wrote:
           | And it's also assuming that any life is like us, with no
           | other technology or way to cycle/recycle heat other than to
           | radiate it into space.
           | 
           | I mean, I know the proof of life is us, but the human-
           | centered view of the universe does reek of prior historical
           | "knowledge" that the earth was the center of the universe. I
           | understand searching for life like us, as that is what we can
           | extrapolate from current data. But to use that to infer that
           | we're it, it's just too much for me.
        
             | cletus wrote:
             | This is the realm of the Fermi Paradox (which is a misnomer
             | because it's not really a paradox at all).
             | 
             | The key question is that if planets are so common and space
             | is so big, why does it seem to be so empty of life? You
             | bring up an argument that maybe life is so different as to
             | be undetectable. It's a fair question to ask but the beauty
             | of the Fermi Paradox is that you don't need to argue about
             | what's most likely. You simply have to be concerned with
             | what's possible.
             | 
             | Let me put it this way. let's say that there is 1 other
             | spacefaring civilization in the Milky Way and they've
             | evolved like you said in a way completely alien to us and
             | as such don't follow a path we can easily detect or at
             | least we don't think to look for it. I can buy that as
             | entirely possible.
             | 
             | But now let's assume there are 1,000 spacefaring
             | civilizations in the Milky Way. What are the odds that
             | every one them falls in this category? What are the odds
             | that _none_ of them follow a similar evolutionary path to
             | us and what we consider highly likely? It becomes
             | increasingly incredulous as you scale up the number of
             | civilizations.
             | 
             | So what's more likely? 1,000 civilizations followed a path
             | alien to us independently? Or that there are few to no
             | other civilizations out there to detect?
             | 
             | To say we're the only 1 of 1,000 to follow this path is
             | really a different kind of human-centric hubris.
             | 
             | Extracting energy from a star is so low-tech it defies
             | logic to think we're the only ones who will (likely) do it.
        
       | JoeAltmaier wrote:
       | Has it been spotted though? Indirect evidence shows something is
       | there. But no one has seen it, not any image has been produced.
        
         | Cthulhu_ wrote:
         | 'detected' would be more accurate, but this is a pop sci take
         | on a press release that says "New planet detected around star
         | closest to the Sun" [1] of a paper called "A candidate short-
         | period sub-Earth orbiting Proxima Centauri" [2]. That's often
         | how it goes, each new medium picking it up adding more and more
         | embellishment, graphics of green-and-blue planets, and
         | breathless fantasizing about one day colonizing the stars.
         | 
         | "Earth-like planet spotted orbiting Sun's closest star" is a
         | lot sexier than "We detect a signal at 5.12 +- 0.04 days with a
         | semi-amplitude of 39 +- 7 cm s-1. The analysis of subsets of
         | the ESPRESSO data, the activity indicators, and chromatic RVs
         | suggest that this signal is not caused by stellar variability
         | but instead by a planetary companion with a minimum mass of
         | 0.26 +- 0.05 M[?] (about twice the mass of Mars) orbiting at
         | 0.029 au from the star. The orbital eccentricity is well
         | constrained and compatible with a circular orbit."
         | 
         | [1] https://www.eso.org/public/news/eso2202/
         | 
         | [2] https://www.aanda.org/10.1051/0004-6361/202142337
        
       | ck2 wrote:
       | I found this little ditty in a linked article way way way more
       | fascinating:
       | 
       | > _Humanity's first chance to explore this nearby world may come
       | from the recently announced Breakthrough Starshot initiative,
       | which plans to build fleets of tiny laser-propelled interstellar
       | probes in the coming decades. Travelling at 20% of the speed of
       | light, they would take about 20 years to cover the 1.3 parsecs
       | from Earth to Proxima Centauri._
        
       | rntn wrote:
       | Sadly, as discussed here, the technical problems with propulsion
       | systems for interstellar travel are non-trivial:
       | 
       | https://news.ycombinator.com/item?id=29638529
       | 
       | Of course that doesn't necessarily preclude a nearby higher level
       | Kardashev Civilization becoming interested in all the noise we're
       | making and heading over.
       | 
       | As we put up systems beyond Webb, it may be possible to observe a
       | hypothetical inbound craft / fleet some years off, which would
       | have interesting effects on our current human society, once it
       | became generally known..
       | 
       | My suspicion is that the social media generation would react a
       | lot worse than the radio generation did to the 1938 broadcast of
       | H. G. Wells' War of the Worlds:
       | 
       | https://www.space.com/40435-finding-aliens-humanity-reaction...
        
         | tokai wrote:
         | I thought the nuclear propulsion options were viable and
         | relative simple.
        
           | natechols wrote:
           | All of the descriptions I've seen were "viable" in the sense
           | of "we could hypothetically accomplish this in a few decades
           | a for around $100 trillion". At least that was the estimate
           | for Project Daedalus, which designed a nuclear pulse
           | propulsion probe to do a 50-year flyby of Barnard's Star. Fun
           | to think about but it's going to be a while before even the
           | largest governments can afford to fund a project that most of
           | its creators will never see completed.
        
           | rbanffy wrote:
           | Even if you get a very high specific impulse, you still need
           | to pack a lot of reaction mass. You'll also need a lot of
           | supplies (or a biome) because even if you get to 0.1 c, it's
           | still 40 years to get there.
        
             | grishka wrote:
             | I'm not losing hope that there are ways to travel faster
             | than the speed of light that we haven't yet discovered,
             | like bending the spacetime around the spacecraft, or
             | wormholes, or something else of that kind. If various forms
             | of rapidly ejecting matter out of a nozzle really are the
             | only physically viable option for spaceflight, it would be
             | an extremely disappointing universe.
        
               | rbanffy wrote:
               | > If various forms of rapidly ejecting matter out of a
               | nozzle really are the only physically viable option for
               | spaceflight, it would be an extremely disappointing
               | universe.
               | 
               | Indeed. If that's the case, the universe is an infinitely
               | big and infinitely boring place.
               | 
               | OTOH, our future uploaded selves may be able to slow down
               | their clock rates and make the trip so much shorter.
               | 
               | And you don't need to leave your dear ones on Earth -
               | just bring forks of them along you (chances are a fork of
               | you will remain on Earth anyway).
        
               | aerique wrote:
               | What would that fork think of it?
        
               | rbanffy wrote:
               | If I were to fork myself in this situation, I'd make one
               | fork who thinks that making the trip will be awesome and
               | another that will think that staying home is the coolest
               | thing.
               | 
               | If we can, from time to time, merge our memories and
               | refork, this wouldn't be a big issue, as both forks would
               | experience both lives.
               | 
               | I think that, at this point, we wouldn't be that much
               | human anymore.
        
               | s1artibartfast wrote:
               | You don't even have to modify it. If you are a person
               | that thinks going and leaving a fork would be cool, and
               | also thinks staying and sending a fork would be cool, the
               | job is done.
        
               | grishka wrote:
               | Frankly, I believe that any form of mind upload or
               | consciousness transfer is a much harder problem than both
               | rejuvenation and interstellar spaceflight.
               | 
               | Looking at current aging research, there's a good
               | possibility we'll see rejuvenation in the next decade or
               | two and it'll profoundly change our society. In 20 years,
               | everyone will be looking 25 years old and pointing at
               | frail people with wrinkly faces and laughing, same way we
               | do today with antivaxxers.
               | 
               | Once that's out of the way, we'll eventually get
               | comfortable with building arbitrarily large objects on
               | orbit, and we could as well build a huge spaceship with
               | an onboard self-sustaining ecosystem and fly _that_ to
               | other stars, the boring way. Yes, it will be a very long
               | journey, but it 's possible without the reliance on yet
               | to be discovered new physics.
        
               | HWR_14 wrote:
               | > pointing at frail people with wrinkly faces and
               | laughing, same way we do today with antivaxxers.
               | 
               | Except those people are more likely to be too poor to
               | afford it instead of unwilling to take it.
        
               | psd1 wrote:
               | Or, worse, the young will never get any power because the
               | old will not relinquish control.
               | 
               | Then you have the "surfeit of princes" problem.
               | 
               | This isn't just grand political power: imagine being
               | unable to progress in your career because geriatrics
               | above you aren't retiring.
               | 
               | That's just one possible secondary effect. We could
               | enumerate many others.
        
               | HWR_14 wrote:
               | Oh yes. That's a very clear concern. I'm reacting to the
               | "people who decline will he like antivaxers" comment. But
               | it seems far more likely people will be priced out as
               | opposed to voluntarily refuse treatment.
        
               | grishka wrote:
               | This logic is flawed. It would be much more economically
               | sensible to just rejuvenate everyone regularly instead of
               | doing what we do today -- try, and eventually fail, to
               | manage all the conditions related to old age. Since aging
               | affects literally everyone, this huge scale would drive
               | the cost of that intervention down to pennies.
               | 
               | Just to be clear: I'm not from the US, we do have not a
               | very good but nevertheless somewhat working public health
               | system over here.
        
               | HWR_14 wrote:
               | > It would be much more economically sensible to just
               | rejuvenate everyone regularly instead of doing what we do
               | today -- try, and eventually fail, to manage all the
               | conditions related to old age.
               | 
               | In the US, we just will do neither for the majority of
               | Americans. If you're too poor to afford rejuvenation,
               | you'll be too poor to afford other treatments. And you'll
               | just die.
               | 
               | Sure the _cost_ of each treatment might be pennies
               | (although it probably will cost a lot and not have those
               | economies of scale) but total profit is not maximized by
               | a smaller markup. Better to get Gates /Bezos/Musk/other
               | billionaires to give you 90% of their fortunes.
        
               | throw1234651234 wrote:
               | That's insane optimism to me. We don't even know how to
               | get a nail to re-attach to a nail bed. We can't put some
               | crystals on a tooth. We can't create a single hair
               | follicle. We have zero non-surgical ways to repair
               | arteries. Etc, etc, etc. We have made zero progress in
               | anti-aging other than controlling blood pressure and
               | identifying harmful chemicals in an environment.
               | 
               | We ARE good at extreme, surgical and or heavy medicating
               | intervention. Doesn't go hand-in-hand with life extension
               | at all.
        
               | forgetfulness wrote:
               | At least there is such a thing as growing tissues from
               | stem cells. Nothing at all in the category of "uploading"
               | one's consciousness anywhere exists. Not "uploading a
               | memory", not "uploading a thought process", those are
               | abstract concepts we've made to describe what the
               | extremely strange organs that brains are do, anyway, and
               | we're nowhere near close to understanding its biology
               | much less replicating what it actually does with a
               | machine.
        
               | grishka wrote:
               | We're now capable of programming cells to produce
               | arbitrary proteins at will, how cool is that?
               | 
               | Also please do look through the playlist in a sibling
               | comment. Michael Levin's research is truly badass. He has
               | grown tadpoles with an extra working eye on the back, and
               | recently he has regrown an amputated leg on a frog.
               | 
               | There's an astonishing amount of untapped possibilities
               | in biology that are opening up only now as we finally
               | have the right tools.
        
               | throw1234651234 wrote:
               | Right, CRISPR is ok, but they haven't figured out that
               | many real applications. This approach to vaccines has
               | actually been around forever.
               | 
               | I bookmarked this thread specifically to watch your links
               | later. I appreciate them and will watch, as I am really
               | interested in the topic.
               | 
               | My _hope_ is that biotech is the next step, but as I
               | mentioned, for now I am highly pessimistic. We can 't
               | seem to treat virtually anything in any real sense,
               | despite the experiments you mention. If anything, the
               | progress in prosthetics (including the spinal bypass) has
               | been great, but nothing to do with life extension or
               | genuine recovery of lost functionality without surgical
               | intervention.
               | 
               | Personally, it seems to be me that the closest thing we
               | can do so far as individuals is reduce risk factors and
               | try to stay high on Death Clocks:
               | https://www.lifespan.io/news/grimage-is-the-best-clock-
               | for-p...
               | 
               | Completely unrelated, but this reminded me that we can't
               | seem to regrow cartilage either. This is a huge issue
               | after cancers and cardiac deaths. Any falls, excessive
               | wear and tear, etc all destroy quality of life with the
               | joints. Latest efforts here:
               | https://www.studyfinds.org/arthritis-pain-regrowing-
               | cartilag...
        
               | grishka wrote:
               | We can now treat a lot of conditions we couldn't before.
               | People used to die all the time of infections or any
               | number of other conditions we now consider fully curable.
               | Medicine as we know it is a relatively young science
               | compared to physics or mathematics for example. We can
               | treat most bacterial infections. We can manage most virus
               | infections. We can perform life-saving, high-precision
               | surgeries. We couldn't do any of these things just 100
               | years ago -- that's nothing on a historical timescale.
               | 
               | Thing is, medicine/biology is a unique field because it
               | relies quite a lot on advancements in other fields for
               | its tools. You couldn't research cells before microscope
               | was invented. You can't begin figuring out what each part
               | of a genome does before you've sequenced it. You can't
               | begin to research functions of specific proteins before
               | you've solved their structures and got the ability to
               | manipulate their production and/or attach markers to
               | them. And so on, and so forth. Not so long ago the main
               | approach in medical research was basically "try stuff
               | randomly on lab animals and see what has a beneficial
               | effect". Now that we can peek into the internal workings
               | of biological systems we can use a more direct, more
               | engineering-like approach.
        
               | virgildotcodes wrote:
               | Any chance you could link to some stuff that's making you
               | so optimistic about rejuvenation on that timeline?
        
               | grishka wrote:
               | https://old.reddit.com/r/longevity has a lot of links to
               | various articles and papers, and I also collect relevant
               | videos and talks into a playlist: https://www.youtube.com
               | /playlist?list=PLLvA7pB41pDk27XOjqbXi...
        
               | roveo wrote:
               | Look up the stuff David Sinclair is doing with his team.
               | They are already rejuvenating and regrowing severed optic
               | nerves with Yamanaka factors in mice and are preparing to
               | start human trials.
               | 
               | It's not rock-solid that this is going to happen for the
               | whole body soon, but some truly breakthrough things are
               | happening right now in this field, nothing like the
               | previous decades.
        
               | Cthulhu_ wrote:
               | At the moment I have more faith that our AI overlords -
               | or, future self-replicating robots, insert various levels
               | of intelligence and self-reliance here - will be the ones
               | going interstellar, not so much us unless we
               | revolutionize spaceflight. That said, the picture of the
               | future that The Expanse investigates seems to be the most
               | realistic, just minus the somewhat magic propulsion
               | system.
        
               | rbanffy wrote:
               | Not a huge problem if, after the robots terraform the
               | planet and build our settlements, I can opt to be printed
               | into a new organic body.
               | 
               | We'll still need some form of magical propulsion or,
               | worse, some magical power source. There aren't many
               | things that can keep providing energy for thousands of
               | years. I'm pretty sure fission is a non-starter here and
               | even nuclear fusion designs would need a source of
               | tritium because, after a couple thousand years, there
               | won't be much left of the initial fuel.
        
         | edgyquant wrote:
         | I don't think we will or should be trying for interstellar at
         | this time; but something being non-trivial doesn't mean we
         | shouldn't do it.
        
         | bottled_poe wrote:
         | With all the messages we're sending I'm sure a curvature
         | propulsion drive is just around the corner ;)
        
         | tjpnz wrote:
         | If Breakthrough Starshot happens some of us may get to at least
         | see it in our lifetimes.
        
       | b3lvedere wrote:
       | "The team used a state-of-the art spectrograph called ESPRESSO"
       | 
       | And suddenly i am imagining lots of very smart people drinking
       | lots of caffeine.
       | 
       | "To find the wobble.."
       | 
       | this is not helping :)
       | 
       | "ESPRESSO is kept in a special room at the observatory, inside a
       | tank "
       | 
       | oh come on ..
        
         | enkrs wrote:
         | Astronomers go to great lengths to name their stuff for good
         | abbreviations. ESPRESSO is actually "Echelle Spectrograph for
         | Rocky Exoplanet- and Stable Spectroscopic Observations"
        
           | strogonoff wrote:
           | Astronomers are known to backronymise:
           | https://en.wikipedia.org/wiki/STEVE
        
       | vegai_ wrote:
       | Perhaps it's too soon after reading The Dark Forest, but uh oh.
        
         | andrew_eit wrote:
         | I bet the sophons are already on their way
        
         | e40 wrote:
         | I just finished the book yesterday. I rank it #1 on my all-time
         | SciFi list. I would say _A Fire Upon the Deep_ is #2 and _Dune_
         | #3.
        
           | carapace wrote:
           | Really? _A Fire Upon the Deep_ and _Dune_ are masterpieces,
           | yes, but _The Dark Forest_ although good isn 't in the same
           | league IMO.
           | 
           | - - - -
           | 
           | Tangent: Have you read Gene Wolfe's _Book of the New Sun_? It
           | 's less famous than the books above, but (IMO) it's in the
           | same rarefied company as _Dune_ and J.R.R. Tolkien 's work.
        
           | minism wrote:
           | I had the same exact thought the moment I finished it.
           | 
           | After a week of reflection, I think it was a slight
           | overreaction -- the book is still very very good but i dont
           | think #1 for me.
           | 
           | But something about the way the story took shape and
           | culminated in the final third of the book was so engaging,
           | and so satisfying. I think I stayed up until 4 or 5AM the
           | night I finished the last 200 pages.
        
         | Karsteski wrote:
         | Fantastic Sci-Fi book series, btw.
         | 
         | Full name is A Remembrance of Earth's Past.
        
         | eloeffler wrote:
         | Let's send them a ping. What could go wrong?
        
       | ilija139 wrote:
       | Just for reference, the planet is 4.0x10^13 kilometres away, if
       | we send our fastest ever probe, and assume it averages the top
       | speed of 586,800 km/h all the way there, it will still take 7,781
       | years to reach the planet.
        
         | chadcmulligan wrote:
         | Under 1g acceleration about 3.5 years
         | 
         | https://www.omnicalculator.com/physics/space-travel
        
           | _fizz_buzz_ wrote:
           | 1) you also need time decelerate
           | 
           | 2) speed of light is a hard limit, you cannot keep
           | accelerating and you need more energy the closer you get to
           | that limit
        
             | tokai wrote:
             | > 1) you also need time decelerate
             | 
             | No that would be a waste of effort. A flyby mission
             | definitely makes the most sense. The 3.5 years are with
             | deceleration though.
        
               | empiricus wrote:
               | You mean flyby at almost the speed of light? For
               | interstellar travel, I think usable flyby speed is almost
               | the same as stop and look around speed.
        
       | NeoTar wrote:
       | Another point for anyone considering whether we should send a
       | space-probe there...
       | 
       | The current fastest man-man object is the Helios 2 space-probe,
       | reaching something like 25 000 kilometres per hour. Proxima
       | Centauri is 1.3020 parsecs away from Earth.
       | 
       | So, just diving one by the other, we'd looking at something like
       | 18 000 years as a rough order of magnitude for sending something
       | from Earth to Proxima Centauri.
       | 
       | You'd be much better off waiting, well, even a thousand years for
       | technology to improve rather than sending something now.
       | 
       | Note: this is a _very_ dodgy line of reasoning. The Helios probe
       | got a massive speed boost from a close encounter with the sun.
       | But even if the speed is wrong by a factor of ten, we 're still
       | looking at somewhere between a thousand and a hundred-thousand
       | years.
        
         | mouzogu wrote:
         | >something like 18 000 years
         | 
         | this is why we don't see any signs of life out there. there
         | really isn't any point in trying to venture beyond your home.
         | universe is just too big even at the speed of light when you
         | start venturing beyond your local group.
        
           | yitchelle wrote:
           | I guess the assumption is their life span is similar to that
           | on our planet. If the life span measured in thousand of
           | years, it will be a different story.
        
             | rbanffy wrote:
             | Lifespan is one thing, but also the "cadence" of life. For
             | a mammal, spending a year in a spaceship is hard. For a
             | brick, spending a thousand years as part of a wall is the
             | natural order of things.
        
           | rbanffy wrote:
           | > even at the speed of light
           | 
           | If you get really close to the speed of light (which is not
           | really practical from a materials engineering standpoint)
           | your time of transit is significantly shorter.
           | 
           | Once these (extremely hard) engineering problems are solved,
           | a trip to the next star can be a week-long affair from your
           | point of view, but your friends back on Earth won't see you
           | for about a decade.
        
             | anders_p wrote:
             | You'd have to get very close to the speed of light, before
             | you'd see any really significant relativistic effects.
             | 
             | That just isn't practically doable with any technology
             | within humanity's reach, probably for centuries. If it ever
             | will be at all.
             | 
             | The amount of energy needed to propel anything at that
             | speed is enormous.
        
               | rbanffy wrote:
               | Unless my math is very wrong, at 0.9c the passenger
               | perceived time is more or less half the perceived time
               | from the departure point. That's already quite
               | significant, although not something I could do over a
               | vacation ;-)
               | 
               | In order to spend a leisurely "cruise-ship" week to
               | Proxima you'd need to go very close to c. At that speed,
               | even friction with a non-ideal vacuum is a problem :-D.
        
             | jsjohnst wrote:
             | > a trip to the next star can be a week-long affair from
             | your point of view
             | 
             | You'd need to travel at around 233x the speed of light to
             | make getting to the _nearest_ star be a week trip, no?
        
               | _Microft wrote:
               | The effect is called time dilation. The section of
               | interest here is ,,Time dilation caused by a relative
               | velocity":
               | 
               | https://en.m.wikipedia.org/wiki/Time_dilation
        
               | jsjohnst wrote:
               | I'm aware of time dilation, my point was that a "week
               | vacation" to something "over 4 light years" away is just
               | hyperbolic.
        
               | rbanffy wrote:
               | From the passenger's point of view, yes. For everyone
               | else you'd be veeeery close to c, but not quite there.
        
               | samatman wrote:
               | Nope! If you obtain the full speed of light then a)
               | you're not made of baryons anymore so congratulations on
               | that and b) no time passes whatsoever between your being
               | emitted in some tight laser beam on planet A, and being
               | transcribed on planet B, from your perspective.
               | 
               | None. Photons don't experience time, they are time.
        
               | rbanffy wrote:
               | Not exactly. For you to think you are traveling 20x
               | faster than light, your friends that stayed at home would
               | have to see you traveling at 0.99995c. For 233x faster
               | than light, that's a lot of 9's in that number.
        
               | [deleted]
        
               | s1artibartfast wrote:
               | There is no faster than light, I can't parse this
               | statement.
        
               | psyc wrote:
               | Distance divided by [time experienced by traveler]. GP is
               | not saying that traveler went faster than light.
        
               | [deleted]
        
               | s1artibartfast wrote:
               | I get 0.999c for 20x and 0.99999c for 220+
        
               | rbanffy wrote:
               | I'll trust your numbers more than mine.
               | 
               | But, for all intents and purposes, this is impossibly
               | fast ;-)
               | 
               | Unless you are on the Bistromath, that is.
        
           | spookthesunset wrote:
           | That is assuming that the speed of light truly is the end-
           | all-be-all. It is quite possible there are other ways of
           | travel that we've yet to discover. I have no idea what they'd
           | be but humans have really only been doing this space /
           | astronomy thing for a few hundred years at most.
           | 
           | We have barely scratched the surface of what is truly going
           | on out there. It would be incredibly "human centric" to think
           | our current understanding of the universe is "it", in my
           | opinion.
        
         | narag wrote:
         | _Another point for anyone considering whether we should send a
         | space-probe there..._
         | 
         | We should and do send probes anywhere that's practical. The
         | question is more like when it will be practical to build star
         | probes.
         | 
         |  _The current fastest man-man object is the..._
         | 
         | The current fastest man-made object wasn't intended to reach
         | the stars.
         | 
         | On the other hand, there are many challenges that make more
         | sense to undertake as previous steps to develop the needed
         | technology.
        
         | netcraft wrote:
         | The formal name for this is the
         | https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calcu...
        
         | _blu wrote:
         | we need to send out a probe now before it's too late
        
           | [deleted]
        
         | xdennis wrote:
         | > 25 000 kilometres per hour
         | 
         | 252 792 km/h
        
         | Udo wrote:
         | I find it enjoyable to think about the technologies that might
         | just be in the cards further into the future.
         | 
         | If we ever figure out light-weight fusion drives, we could
         | build _light hugger_ space ships that accelerate to a decent
         | fraction of the speed of light. At 1g acceleration it takes
         | about one year to get to 0.9c, which would make the Proxima
         | system accessible with a travel time of about 6 years. Or 8
         | years at 0.5g. Or 9 years if we  'only' get to 0.5c.
         | 
         | The same goes for laser-driven light sails if we just wanted to
         | send a probe, although deceleration would be an issue. (There
         | is currently an aspirational research project for this called
         | Breakthrough Starshot)
         | 
         | The exciting thing about these technologies is that they don't
         | require new physics in principle, just a lot of engineering. Of
         | course, uploaded minds would probably always be better suited
         | for space travel, but it's neat to know that even biological
         | people could in theory make these trips.
        
           | withinboredom wrote:
           | IIRC, the limit with humans on-board is like .3c due to the
           | red/blue shifting of the background radiation of the
           | universe. At about .3c, it turns into microwaves/radar/x-rays
           | and such, becoming quite bad for humans. There's so much
           | background radiation, there may be no way to adequately
           | shield from it and/or travel may be limited only in the
           | direction of less background radiation.
           | 
           | Maybe someone has a link to more information, that's just
           | what I remember from years ago.
        
             | ffhhj wrote:
             | Right, also the hull must resist the impact against
             | hidrogen atoms at near the speed of light, which would
             | apply tremendous forces. Dust will be like exploding nukes.
        
             | Udo wrote:
             | That's a good point. I have no idea actually where the
             | practical limits would be, especially considering options
             | that arise if the ship has access to a lot of electrical
             | power to generate a protective magnetic field. But even at
             | 0.3c, the trip to Proxima could still be worthwhile for an
             | unmodified human.
        
               | anders_p wrote:
               | You still have the deceleration issue.
               | 
               | You need to use the same amount of energy and time to
               | decelerate, as you did to accelerate.
               | 
               | So you'd only be able to sustain constant acceleration
               | for half the distance. Then deceleration for the second
               | half of the journey.
               | 
               | That would make the travel time much, much longer than
               | your calculations, since you'd be traveling at relatively
               | slow speed for both the first & last 20-25% of the
               | distance.
        
               | [deleted]
        
             | IHLayman wrote:
             | Here's a link to a Gizmodo article talking about the
             | study... unfortunately I can't get the original study to
             | load: https://gizmodo.com/this-is-what-it-would-really-
             | look-like-t...
        
           | iam-TJ wrote:
           | Whenever I read discussions about space travel and trying to
           | approach the speed of light for human travel I have the
           | feeling there's a lot of tunnel vision (excuse the pun). It
           | always seems to assume travelling along a linear path through
           | space.
           | 
           | In my mind, using the admittedly poor analogy of space-time
           | as a membrane that is distorted by gravity, my thinking is
           | we'll find some way to effectively bring two points in space-
           | time adjacent to each other and 'step' between them.
           | Wormholes, Warp, or whatever you want to call it.
           | 
           | Think of a flexible membrane 10 meters long and we are going
           | to travel from one end to the other. We can either travel in
           | a linear fashion over its surface for 10 meters or we can
           | wrap the membrane so both ends are next to each other and
           | travel 0.01m across the gap between them.
           | 
           | Yes, I know there are all sorts of obstacles and arguments
           | against this simplistic visualisation but this is how I've
           | always imagined the physics of any science fiction faster-
           | than-light travel - worm-holes, warp drives, etc.
           | 
           | If you want an actual, real, possible-right-now analogy,
           | think of our current situation where the fastest way to
           | travel from London, UK to Sydney, Australia (1/2 way around
           | the world) is through the atmosphere in an aeroplane
           | travelling ~17000 kilometers and taking at best 19.5 hours.
           | 
           | SpaceX (Musk) Virgin Galactic (Branson), other companies [0],
           | and space agencies [1] have talked about, and are actively
           | working toward, stepping outside the atmosphere into space to
           | reduce the time element to around an hour.
           | 
           | So just like with supposedly faster-than-light travel, by
           | 'stepping outside' the linear/conventional thinking/physics
           | we reduce the time of travel element dramatically. The start
           | and end points don't move but the distance travelled by the
           | transport vehicle itself changes in order to enable the
           | reduction in time.
           | 
           | [0] https://www.telegraph.co.uk/travel/news/new-flights-
           | space-lo...
           | 
           | [1] https://edition.cnn.com/travel/article/hypersonic-flight-
           | air...
        
             | [deleted]
        
             | at_a_remove wrote:
             | I've never bought it. It will still involve being able to
             | transfer information FTL, and then you're on to the
             | Grandfather Paradox.
             | 
             | On top of it, let's handwave all of this away, poof. Any
             | aliens anywhere in the Universe would also be using it once
             | their technology got to that level. Just from the lack of
             | visitors, we have three possibilities that are immediately
             | evident:
             | 
             | 1) Humans are among the first intelligent species to get to
             | this technology in _the entire Universe_.
             | 
             | 2) Other species have it, _but_ all of them, every last
             | far-flung one of them, even the renegade civilizations or
             | the mad scientists at the individual level, abide by not
             | using it around humans. Despite all of their numerous
             | reasoning capacities and utterly inhuman motivations, every
             | last sophont with access to the tech has agreed upon this,
             | and has for thousands of years.
             | 
             | 3) That tech can't exist.
             | 
             | The first and second are _unlikely_ , statistically.
        
           | messe wrote:
           | > If we ever figure out light-weight fusion drives, we could
           | build light hugger space ships that accelerate to a decent
           | fraction of the speed of light. At 1g acceleration it takes
           | about one year to get to 0.9c, which would make the Proxima
           | system accessible with a travel time of about 6 years. Or 8
           | years at 0.5g. Or 9 years if we 'only' get to 0.5c.
           | 
           | No, we couldn't. The energy density of fusion isn't anywhere
           | near close enough to make a lighthugger, you'd need insane
           | mass ratios[1] and ramjets are probably unfeasible (as in,
           | even-if-your-a-Kardeshev-II-civilization-unfeasible[2]).
           | 
           | [1]: http://www.projectrho.com/public_html/rocket/slowerlight
           | 3.ph...
           | 
           | [2]: https://www.sciencedirect.com/science/article/pii/S00945
           | 7652...
        
             | thereddaikon wrote:
             | Another atomic rockets enjoyer. I've killed so much time on
             | that site. I don't agree with every one of Winchell's
             | conclusions. But they are small things. And I don't know of
             | a more comprehensive and grounded take on future
             | spaceflight technologies.
        
               | messe wrote:
               | I was saddened to hear about Winchell's cancer diagnosis
               | last year[1]. I've wasted a ton of time there too, it's
               | an oddity compared to the rest of the modern internet. I
               | know very few other useful sites like it, and I love it
               | all the more for its strange aesthetic.
               | 
               | I don't agree with everything there either, but usually
               | it's only very minor gripes. In this case though, it's
               | hard to argue with the reality of the rocket equation.
               | 
               | [1]: https://twitter.com/nyrath/status/143601098708628685
               | 3?s=20
        
               | thereddaikon wrote:
               | Oh man, I hadn't heard about that. Best of luck to him
               | but he's right prostate cancer is a pretty bad one.
               | 
               | What are the other few sites you do know of?
               | 
               | And you are absolutely right about the rocket equation.
               | You can't really get around it.
        
               | messe wrote:
               | I'm sure there's more but the first few that come to mind
               | are Greg Egan's homepage[1], Xenology[2], and on a
               | completely different topic "Gramadach na Gaeilge"[3]
               | (Irish Grammar).
               | 
               | [1]: https://gregegan.net
               | 
               | [2]: https://xenology.info
               | 
               | [3]: http://nualeargais.ie/gnag/gram.htm
        
           | treeman79 wrote:
           | Bits of dust or a pebble hitting ship at 0.5c would make for
           | a bad day.
        
           | rmbyrro wrote:
           | This is exciting stuff indeed. Imagine a year-4,000 spaceship
           | reaching Centauri before another spaceship dispatched 1,000
           | years before it?
           | 
           | For the cynical or pessimists: I'm not _optimistic_ about
           | humanity reaching year-4,000, I 'm just _possibilistic_ about
           | it (as in the philosophical meaning [1]).
           | 
           | [1] https://en.wikipedia.org/wiki/Actualism#:~:text=possibili
           | sm,...
        
             | rbanffy wrote:
             | This is more or less the plot of a story by Brazilian
             | science fiction writer Roberto Luiz Calife.
        
               | natechols wrote:
               | And the story "Far Centaurus" by A.E. Van Vogt.
        
             | Andrew_nenakhov wrote:
             | This is literally the plot of a very old computer game
             | Alien Legacy. [0]
             | 
             | [0]: https://en.m.wikipedia.org/wiki/Alien_Legacy
        
             | s1artibartfast wrote:
             | I can't imagine humanity not making it to 4000. There are
             | very few true existential threats.
        
           | michaelerule wrote:
           | Is the 6 years measured in the time-frame of a passenger on
           | the spacecraft, or as observed from Earth?
        
             | Udo wrote:
             | At 0.9c the relativistic time dilation is such that 2.3
             | days on Earth pass for every day shipboard time, meaning
             | the crew would experience less than 4 years of travel in
             | total: https://www.fourmilab.ch/cship/timedial.html
        
             | raxxorrax wrote:
             | Since we aren't too fast yet, it would basically be the
             | same.
        
           | 74B5 wrote:
           | Thank you for your optimism, now let me balance that out a
           | little.
           | 
           | Propulsion maybe the easier part of engineering. Afaik we are
           | nowhere near to life support and environment control that
           | could be considered stable for a time period of maybe 10
           | years or more.
           | 
           | The biggest biological advantage, adaptation is meaningless
           | for large organism on such a timescale and maybe dangerous on
           | a microbial level.
        
             | Udo wrote:
             | You are correct that we are nowhere near that in life
             | support technology, however, there don't seem to be an
             | _fundamental_ hurdles there. If we end up opting for a
             | biological life support system, adaptation would not even
             | enter the equation - it 'd be a matter of genetic
             | engineering. An obvious danger would always be onboard
             | ecosystem collapse, of course.
        
         | gameswithgo wrote:
         | with how small you can make a probe today there isn't any
         | barrier to making something 100x faster or more. throw up a
         | small camera and transmitter with a huge ion thruster thank on
         | top of a saturn v sized rocket of your choice and you will get
         | going very fast
        
         | throw1234651234 wrote:
         | The other problem with sending a space probe is that the devs
         | will have to actually deliver the Proxima Centauri mod on time
         | and on budget, which, let's be honest, probably isn't going to
         | happen for another few years. Think about it, you have to skin
         | the whole planet, make sure the AI isn't weird, make sure it
         | doesn't conflict with the existing storyline or retcon all the
         | earth NPC memories. It's a HUGE project. Right now we just
         | literally return a light curve from the function when someone
         | looks at it.
         | 
         | And even if we could get the adversial networks to model all
         | this garbage, etc it needs to line up with the plan of the rest
         | of the Universe from the franchise and the managers can't even
         | decide whether the photon is going to be a wave or a particle.
         | Jeez. Vaporware like HL2.
        
         | [deleted]
        
         | dmarchuk wrote:
         | Isn't Parker Solar Probe much faster than that? It's supposed
         | to be going hundreds of thousands of km/h. [1]
         | 
         | [1] https://en.wikipedia.org/wiki/Parker_Solar_Probe
        
           | galacticaactual wrote:
           | It achieved those speeds by falling into a gravity well.
           | Reaching Alpha Centauri requires escaping one.
        
             | netcraft wrote:
             | I very well may be wrong about this, but I believe thats
             | not exactly true. Parker required the fasted launch as of
             | its time because it had to shed the momentum of the earth
             | that it started with to be able to fall into that gravity
             | well.
             | 
             | quoting from reddit:
             | 
             | > You may be thinking of the Sun as a big gravity well and
             | how you can just drop things in a well. But orbits don't
             | work anything like that at all. Sure if you are stationary
             | relative to the Sun then you'll fall right into it. But
             | anything that leaves Earth is very far from stationary.
             | You're going at 30 km/s 90 degrees off your target.
             | Possibly the first idea many people think of if they want
             | to hit the Sun is to cancel that 30 km/s of speed, and sure
             | it'll work. But you need 30 km/s of delta-v. On the other
             | hand, to escape the solar system from Earth you only need a
             | velocity of 42 km/s relative to the Sun, of which you
             | already have 30 km/s. So you only need to increase your
             | speed by about 12 km/s. (And for both cases add one or two
             | km/s to counter Earth's gravity.)
             | 
             | https://www.reddit.com/r/askscience/comments/wjv87/comment/
             | c...
             | 
             | https://www.forbes.com/sites/startswithabang/2019/09/20/thi
             | s...
        
               | [deleted]
        
           | Fatnino wrote:
           | Yes, Parker breaks the 40+ year old record set by Helios. OP
           | is using stale data.
           | 
           | The fastest crewed spaceship was Apollo 10 at 39,705km/h
           | before reentry. After orbiting the moon they had lots of fuel
           | left over so they just floored the engine on the way home.
           | Not just falling back towards the planet but actively flying
           | towards the ground for longer than any other Apollo mission.
           | 
           | This record can be broken with current technology, we just
           | have to go back to the moon.
        
         | uwuemu wrote:
         | A probe based on nuclear pulse propulsion could do it in around
         | 50 years, with today's technology. It's not that we can't do it
         | fast (within one average human lifespan), it's that the project
         | would be very expensive and something like Nasa has a
         | relatively tight budget.
         | 
         | I mean we, as humanity, have to have an eccentric billionaire
         | start a Martian fire (SpaceX Starship) under our lazy asses to
         | even start to think about getting to Mars in a reasonable
         | timeframe and in reasonable numbers (to start a colony). We are
         | not funding making our species multiplanetary for the last few
         | decades because we were too lazy, how can anyone expect us
         | sending anything to the closest star (other than the sun)...
         | You can't.
        
           | Tepix wrote:
           | We do in fact have another billionaire, Yuri Millner, to push
           | humanity towards the goal of reaching other stars with his
           | "Breakthrough Starshot" initiative.
        
           | semi-extrinsic wrote:
           | Maybe an unpopular opinion, but Musk is just plain wrong when
           | he thinks there is any urgency to Mars exploration (or it's
           | just vicarious arguments because rockets are cool).
           | 
           | Basically, the tech you need to make a Mars colony truly self
           | sufficient is something like a compact fusion powerplant.
           | 
           | Before we have that, no point in worrying about using Mars as
           | a "backup plan", because if Earth was screwed, Mars would
           | have a couple of years to live at most.
           | 
           | And obviously it would be vastly better for humanity if Musk
           | spent money on zero-emission large scale energy production,
           | than on rockets.
        
             | mavhc wrote:
             | He should really thing about making a company to do solar,
             | and maybe an Electric Car company that outsells every other
             | USA EV company 10:1
        
             | moffkalast wrote:
             | There is an inherent urgency in all of his plans, mainly
             | because he wants to see it done within his lifetime. He's
             | got 40 years left tops, but more like 20 during which he
             | could still theoretically do anything significant in.
             | Rockets take decades to develop.
        
             | alsaaro wrote:
             | One conceivable reason to colonize Mars is real estate.
             | 
             | Perhaps in the near future life extension technology will
             | become common place, people may continue to have kids, but
             | natural deaths may be rare; the human population will
             | increase exponentially and need somewhere to live and
             | something to do -- terraforming Mars in exchange for
             | property may be reasonable.
        
             | brimble wrote:
             | The Mars backup plan seems kinda dumb to me because Mars is
             | worse _as is_ than all but the very worst post-apocalyptic
             | Earth scenarios.
             | 
             | Just build bunkers here and staff them in shifts. Much
             | cheaper.
             | 
             | Your remaining threats for which Mars would be better than
             | "ruined" Earth are something like a grey goo event, or an
             | asteroid so large that it liquefies much of the crust
             | (killing everyone in all your bunkers). So, a fair bit
             | bigger than the one that killed the Dinosaurs.
             | 
             | I am very interested in watching people try to colonize
             | Mars, but find the "backup for Earth" argument ridiculous,
             | especially if presented as something urgent.
        
             | politician wrote:
             | This is hopeful negativism.
             | 
             | - They don't need fusion. A StarShip can deposit hundreds
             | of solar panels and put them on the ground. No, dust isn't
             | an issue because they'll bring a roomba. No, this isn't a
             | joke, NASA martian probes' solar panels were cleaned by a
             | light Martian breeze.
             | 
             | - They will be able to become self-sufficient rapidly.
             | They're not going to send 1M tons of cargo to Mars without
             | a deployment plan. SpaceX and Tesla have already
             | demonstrated effective vertically integrated supply chains
             | and manufacturing. They have the institutional knowledge to
             | mine raw materials and build factories that build complex
             | parts.
             | 
             | - There are plenty of other Earth-bound governments and
             | billionaires that could devote funds to zero-emission large
             | scale energy production projects. Musk, his companies and
             | assets amount to a very small fraction of the global
             | economy. Your ire is misdirected: your anger about the
             | situation is properly directed at the rule of corrupt
             | imbeciles and their questionable resource allocation
             | decisions (Netflix, coal, etc.) here on Earth rather than
             | one team of folks who seem extraordinarily mission driven
             | and effective.
        
               | samatman wrote:
               | Mars has dust storms which last months or years, it has
               | no ionosphere, and that dust contains enough perchlorates
               | to poison anything we could eat, including us. Ok, that
               | sentence went somewhere odd at the end but, it's true.
               | 
               | A large asteroid has only one of these problems, by
               | virtue of not coming with any atmosphere, ionic or
               | otherwise.
               | 
               | I kinda hope Elon is bluffing and actually plans to head
               | to the Belt. I've penciled it out and and he'd have to be
               | insane not to. Surely he has pencils as well.
        
               | ethbr0 wrote:
               | Isn't long term zero-g pretty hostile to our biology?
        
               | lanstin wrote:
               | Hollow out the asteroid and spin it.
        
               | Tepix wrote:
               | That tech is decades in the future.
        
               | ethbr0 wrote:
               | Is it? Assuming an asteroid of appropriate structural
               | strength, it's just a question of time + propulsion. And
               | acceleration adds up pretty quickly when you're in a
               | vacuum and have all the time you want.
        
               | edgyquant wrote:
               | This wouldn't work, asteroids are like gravel there isn't
               | really anything to hollow out and even if you did when
               | you spun it the asteroid would just shoot these rocks out
               | in all directions.
        
               | kibwen wrote:
               | Mars is 0.3 G, which is just as hostile for long-term
               | habitation. No human child conceived, born, and raised in
               | that environment would have the ability to stand on Earth
               | without an Aliens-style rigid exosuit. Their heart might
               | not even be capable of pumping blood to their head.
        
               | ErikCorry wrote:
               | Nobody knows what 0.3 g does to the body because we've
               | spent 20 years on the ISS doing zero-g "science" even
               | after the most important question was answered:
               | 
               | Q: What does zero-g do to the human body?
               | 
               | A: It's really really unhealthy.
        
               | spookthesunset wrote:
               | The Martian dust storms are pretty tame. Nothing like
               | portrayed in the movies. The atmosphere is 1% of what it
               | is here on earth.
               | 
               | So while it is a "storm" it isn't like a tropical force
               | hurricane or anything. More like a very minor annoyance
               | that deposits a bit more Martian dust on your stuff over
               | time.
        
               | eternalban wrote:
               | What's the story on navigating in the belt? Approach
               | specific target from above or reasonably safe to traverse
               | it and explore?
        
               | GoblinSlayer wrote:
               | >They're not going to send 1M tons of cargo to Mars
               | without a deployment plan.
               | 
               | Can this happen? I imagine before we can settle on Mars
               | we first should be comfortable flying there, and the
               | latter should be sufficient for asteroid mining. But,
               | right, our technology is just not at a comfortable level
               | yet.
        
             | s1artibartfast wrote:
             | >And obviously it would be vastly better for humanity if
             | Musk spent money on zero-emission large scale energy
             | production, than on rockets.
             | 
             | Classic zero sum thinking. Spacex doesn't cost money, it
             | makes it. How much money do you think Musk put into it? The
             | answer is ~100 million seed. It is now worth 35,000
             | million.
             | 
             | How far do you think that 100m would go to develop fusion.
             | The ITER project alone costs 65,000 million.
        
             | ufmace wrote:
             | I don't think that a compact fusion powerplant specifically
             | is needed. But I do agree that a truly self-sufficient
             | Martian colony (I.E. able to exist for more than a few
             | years without ships coming from Earth) would need a
             | gargantuan level of infrastructure to have even a small
             | chance of being viable.
             | 
             | From a standpoint of reducing emissions on Earth, it would
             | be cool to see Elon Musk's best take on how to build a
             | practical fusion generator though. I've heard of a few
             | potential paths that could lead to net power much faster
             | and cheaper than ITER. Supposedly superconducting magnets
             | have gotten considerably better since ITER was proposed,
             | and since power output in a tokamak reactor is something
             | like the third or fourth power of the magnet strength IIRC,
             | there's potential for a newer and smaller reactor design to
             | outdo it in both timeline and cost.
        
             | oceanplexian wrote:
             | > Musk is just plain wrong when he thinks there is any
             | urgency to Mars exploration (or it's just vicarious
             | arguments because rockets are cool).
             | 
             | Mars might not be sustainable in our lifetime but in a
             | century or two? I think it's within the realm of
             | possibility.
             | 
             | As for the urgency, the last two years has demonstrated the
             | exact opposite to me. Modern civilization is a hop, skip,
             | and a jump away from instability and disaster. When you say
             | that we should instead spend resources on large zero-
             | emissions energy production, well, we've had Nuclear
             | Fission for half a century. The reason we didn't use it to
             | prevent Climate Change is 90% political, not technical,
             | another problem that having a self-sustaining colony,
             | outside the sphere of Earth's influence, would solve.
        
               | ako wrote:
               | Even if we completely screw up liveability on earth, it's
               | probably still going to be way more hospitable then most
               | planets we can reach.
        
               | kibwen wrote:
               | In addition to the fact that there's almost nothing you
               | could do to Earth that would make it less liveable than
               | Mars, any political problem that plagues the Earth is
               | going to plague Mars just as easily. Earth didn't create
               | human political problems, humans did. The only way to
               | keep political problems from plaguing Mars would be to
               | keep humans off of it.
        
               | wtetzner wrote:
               | > As for the urgency, the last two years has demonstrated
               | the exact opposite to me. Modern civilization is a hop,
               | skip, and a jump away from instability and disaster.
               | 
               | I mean, you would somehow have to make Earth less
               | hospitable than Mars to make the effort worth it.
        
               | ethbr0 wrote:
               | > _The reason we didn 't use [Nuclear Fission] to prevent
               | Climate Change is 90% political, not technical_
               | 
               | Eh. The physics and proliferation risk are pretty
               | intertwined.
               | 
               | Who's to say we would have been better off with greater
               | historical nuclear weapon proliferation risk but lower
               | climate risk?
               | 
               | We know the path we chose, limited global use of fission
               | power, mostly avoided nuclear weapons proliferation, and
               | did avoid nuclear exchanges. So it's provably a
               | successful (or probably successful) path. Whether an
               | alternative would have gotten the same outcome?
        
               | monkeywork wrote:
               | >We know the path we chose, limited global use of fission
               | power, mostly avoided nuclear weapons proliferation, and
               | did avoid nuclear exchanges. So it's provably a
               | successful (or probably successful) path.
               | 
               | Only if you value the lack of nuclear exchanges over the
               | impacts of climate change. Which one of the two is more
               | likely to cause a mass extinction type issue on the
               | planet, one puts the control in the hands of people and
               | the other the forces of nature.
        
               | ethbr0 wrote:
               | I'd say I do. Climate change is colossal in problem
               | magnitude, but temporally slow and distributed in impact.
               | Nuclear weapons are terrifying fast and centralized in
               | impact.
               | 
               | Unfortunately, our civilization is also mostly
               | centralized. Cities, ports, highly productive land :
               | total land area.
               | 
               | If you're talking persistent radioactive effects for a
               | decade+, it doesn't take many to severely cripple the
               | world.
               | 
               | As an example, a 100kt weapon (or smaller dirty) could
               | knock a port out of action. Now look at a list of ports
               | [0] and imagine what would happen if one or more of them
               | dropped off the global trade grid for multiple years.
               | 
               | [0] https://en.m.wikipedia.org/wiki/List_of_busiest_conta
               | iner_po...
        
               | qwytw wrote:
               | How would the increase in the number of nuclear power
               | plants lead to more nuclear weapons? There is no direct
               | connection besides edge cases like Iran using it as a
               | cover to develop nuclear weapons.
        
               | ethbr0 wrote:
               | Someone please correct me if I'm speaking inaccurately,
               | but early reactor design (1950s/60s/70s) focused on light
               | water reactors, which meant enriched U-235 fuel (@ ~3%?).
               | By design, these reactors also convert a portion of their
               | U-238 to P-239, only some of which is then consumed in
               | the reactor.
               | 
               | Consequently, for widespread nuclear reactors (read: in
               | many countries), you also had widespread proliferation of
               | lightly enriched uranium (in the fuel) and proliferation
               | of plutonium (produced in the fuel as the reactor runs).
               | 
               | Both of these remove the most time and energy consuming
               | step (low level enrichment) as an obstacle to state
               | nuclear weapons development.
               | 
               | And they're fundamental to the way light water reactor
               | technology works, especially with the limitations of the
               | period. So the only way you could have had proliferation-
               | resistance would have been to have some sort of global
               | fuel-control and -custody agreement (presumably run by
               | the United States, USSR, and maybe France, depending on
               | the time period). Which sovereign countries would have
               | likely felt some kind of way about.
        
               | qwytw wrote:
               | The number of new nuclear reactors only stopped growing
               | in the 80's. In any case I don't think access to material
               | is the limiting factor in nuclear proliferation. If we're
               | talking about the US and USSR, it's completely
               | irrelevant, even if they had 100x more reactors since
               | they already have more than enough bombs to more or less
               | to blow up the entire world. Other western countries
               | either have enough nukes already or don't need or want
               | them and I don't see why would they export technology or
               | material to countries which are hostile to them.
               | 
               | It's not obvious to me that having more nuclear reactors
               | in the US, Britain or Germany would had made it
               | significantly easier for rogue states like Iraq, Iran or
               | North Korea to developed nuclear weapons.
        
           | monkeywork wrote:
           | Do you have any suggested reading about:
           | 
           | "A probe based on nuclear pulse propulsion could do it in
           | around 50 years, with today's technology."
           | 
           | I was always under the impression that these vast distances
           | were basically entire unreachable in several human lifetimes.
        
             | T-A wrote:
             | The canonical reference is Project Daedalus:
             | 
             | https://en.wikipedia.org/wiki/Project_Daedalus
        
             | ncmncm wrote:
             | Is talking about detonating nukes behind a ship with a big
             | shield behind it.
        
           | politician wrote:
           | The only humans who will be utilizing space in earnest are
           | the Martians. Terrans will be confined to their local space
           | with overwatch on the Moon.
        
             | dsign wrote:
             | > ... overwatch on the Moon.
             | 
             | I'm pretty sure not even that.
        
           | chrisco255 wrote:
           | Why is it weird that a private corporation is doing space
           | exploration & technology? Most of the biggest sailing
           | expeditions were undertaken by private individuals and
           | companies (although often under the funding of a royal
           | family). Locomotives and airplanes were also created and
           | perfected by private individuals / companies.
           | 
           | The 1950s-2000s NASA model for space exploration was unusual
           | in its centralized approach.
        
             | ethbr0 wrote:
             | There's an argument to be made that some of the current
             | largest market cap companies in the world are analogous to
             | royal families, in terms of centralization of capital vs
             | freedom of decision making.
        
               | s1artibartfast wrote:
               | The notable difference is that they don't have a monopoly
               | on violence
        
               | qwytw wrote:
               | Most premodern states (at least) in Europe didn't really
               | have a monopoly on violence in the strict sense either.
               | Kings were constrained by a variety of laws and customs
               | which they couldn't easily change without triggering
               | violent opposition and had to co-opt the local elites
               | (who usually acted as independent actors) whenever they
               | wanted to impose their will outside of the area they
               | directly controlled. Even an 'absolute' ruler like Louis
               | XVI had very limited direct power compared to many modern
               | governments.
        
               | s1artibartfast wrote:
               | Fair enough, it seems that you are primarily attacking
               | the word Monopoly. What if we were to soften the claim to
               | dominance. Rulers always maintained power based on their
               | ability to resist violence from within and without.
               | Economic leverage only existed as long as one could
               | protect themselves from violent opposition. A trade
               | embargo meant nothing if the opposition can seize your
               | assets and production by force.
               | 
               | In today's world, mega corporations have no defense if a
               | government actor decides to use force against them.
               | 
               | This utter defenselessness against violence is the main
               | difference between a modern corporation and a feudal
               | actor.
        
               | ethbr0 wrote:
               | Good point. See: ARM China
        
             | qwytw wrote:
             | Most of those private expeditions were seeking short term
             | profit (of course there exceptions like the
             | Arctic/Antarctic expeditions but their budgets were
             | relatively insignificant compared to the resources required
             | to send several ships to India or the Americas in the 15th
             | century or a spaceship to Mars. Even if colonizing and
             | exploiting the mineral resources on Mars could be
             | profitable in the longterm being the first on Mars (unlike
             | being the first to sail to India) is definitely going to
             | cost more than it's worth (in financial terms) so no
             | rational private company would do this.
        
           | ziggus wrote:
           | "...with today's technology..."
           | 
           | So we have the ability today to move 50K tons of parts into
           | orbit, and come up with vast quantities of helium-3?
        
           | seventytwo wrote:
           | The best thing we could do for space exploration is to figure
           | out terrestrial fusion.
        
           | spaetzleesser wrote:
           | Going to Mars seems pretty useless to me at this time. It's a
           | super hostile environment and we don't have the technology
           | yet to have a self sustaining base there. Give it a few
           | decades and progress in robotics will make a Mars base much
           | easier. There is plenty of work to be done on Earth. We have
           | to solve clean energy production and in general reduce
           | pollution. These are massive technological challenges that
           | deserve massive funding.
        
             | gibolt wrote:
             | Do you expect traveling multiple light years to an alien
             | world to be easier or less hostile? You have to start
             | somewhere, and the selection is pretty thin.
        
               | spaetzleesser wrote:
               | Traveling multiple light years is out of the question.
               | You can think about some concepts but it's simple not
               | doable at this point no matter the budget.
        
             | moffkalast wrote:
             | Tbf, it'll also take us a few decades to get human Mars
             | transit figured out so sounds like we're on schedule.
        
             | oceanplexian wrote:
             | It sounds like a very chicken or egg problem to me, who's
             | to say that progress in robotics doesn't come from trying
             | to establish a base on Mars? Progress is often times non-
             | linear, I mean here we using computers and communication
             | technology based on Integrated Circuits technology
             | furthered by the Apollo program; say we never went to the
             | moon, computing technology and Moore's law might have been
             | set back a decade or two.
        
               | spaetzleesser wrote:
               | I am not against Mars but I just think it's premature.
               | Build up robotics for a while and Mars will be much
               | easier. There is no rush to become a multi planetary
               | species. There is no credible threat of a big asteroid or
               | volcano in the next decades. All threats we may be facing
               | are self made.
               | 
               | My favorite moonshot project would be to create robotics
               | that can clean up the environment and handle recycling.
               | Having the technology to pick up dog poop and plastic
               | bags in an efficient and affordable manner or separating
               | recycling items would be a huge technological challenge
               | that would create a ton of spin-off opportunities
               | including a base on Mars. Or clean up the pacific garbage
               | patch with robots.
        
               | R0b0t1 wrote:
               | I think all of this is premature. Focusing on life
               | extension technology and life science would see a lot of
               | other technological benefit, and in the worst case just
               | mean we can wait it out.
        
             | BurningFrog wrote:
             | If you think going to Mars is useless, don't go.
             | 
             | Just don't stand in the way of those who chose to go.
        
             | cduzz wrote:
             | Totally agree!
             | 
             | However, it's likely that one task (going to Mars, even
             | sending a couple rich bozos there) is small enough that you
             | can probably do that and work on fixing things "at home".
             | 
             | In fact, one could argue that one set of big companies that
             | exist this decade that didn't exist last decade is just a
             | shopping list of "Crap I'll need for my martian condo"
        
             | Drainik wrote:
             | Did you know NASA only get 0.36% of the US Federal budget?
             | Everything else gets "massive funding".
        
               | throwaway1777 wrote:
               | Makes sense though because earth is a dump and extremely
               | corrupt. Even if you were able to substantially decrease
               | military funding (the usual scapegoat) without massively
               | changing the world order we still probably wouldn't spend
               | more on nasa, we would spend it on healthcare,
               | infrastructure, economic bailouts, education, green tech,
               | etc.
        
             | mauvehaus wrote:
             | _Because it 's there_
             | 
             | https://blog.theclymb.com/out-there/because-its-there-the-
             | qu...
        
             | mannerheim wrote:
             | Mars can already be useful as a springboard for space
             | exploration. It's a literal stepping stone, both closer to
             | the belt and outer planets in terms of distance, but also
             | in terms of delta-v, since both the gravity well on Mars is
             | smaller, and it's higher up in the Sun's gravity well, too.
             | Any future space exploration and exploitation will be made
             | tremendously easier if you can launch from Mars instead of
             | Earth.
        
               | ncmncm wrote:
               | Mars is, even at absolute best, a dump: dry, cold,
               | airless, at the bottom of a gravity well, and subject to
               | dust storms besides.
               | 
               | We can build _much better_ outside of gravity wells.
               | Whatever you would land on Mars is more useful in solar
               | orbit, parked next to any convenient asteroid.
        
             | ethbr0 wrote:
             | _Going to {the Middle East, Europe / Asia, Australia, the
             | New World, interior South America, the North American West)
             | seems pretty useless to me at this time. It's a super
             | hostile environment and we don't have the technology yet to
             | have a self sustaining base there. Give it a few decades
             | and progress in {insert technology} will make a base much
             | easier. There is plenty of work to be done on {current
             | place}. We have to solve {current problems}. These are
             | massive technological challenges that deserve massive
             | funding._
             | 
             | ... has been said for the entirety of human history. And in
             | all that time, they've only ever been right about
             | Australia. (J/k Aussies!)
             | 
             | Only one technology matters: that which enables
             | transportation.
             | 
             | Animal husbandry. Sailing. Railroads.
             | 
             | In the end, humans are plentiful. As long as it's done in
             | full disclosure and as an uncoerced individual choice, who
             | the hell are we to stand in the way of adventurers taking a
             | chance on a better life?
        
               | otabdeveloper4 wrote:
               | Nobody ever believed that America is a super-hostile
               | environment.
        
               | ethbr0 wrote:
               | Roanoke, Ajacan, Fort Caroline, Sable Island,
               | Charlesfort, Pensacola, San Miguel de Gualdape,
               | Charlesbourg-Royal, France-Roy, Pensacola?
        
               | TheOtherHobbes wrote:
               | This is absolutely, objectively, incorrect.
               | 
               | You might as well argue that you can build a self-
               | sustaining base on Antarctica.
               | 
               | Of course you can't, because Antarctica can't support
               | life. No amount of shouting into a bullhorn about
               | adventure will change that.
               | 
               | It _might_ be possible with an absolutely epic effort to
               | airlift soil, nuclear reactors, nuclear and other fuels,
               | machinery for every eventually (including chip fabs), raw
               | materials that aren 't locally available (which means
               | almost all of them), and habitable structures.
               | 
               | At the end of that epic effort you'll have something that
               | will barely have a toe-hold on long-term survivability.
               | Possibly. If you're lucky.
               | 
               | Not only is Mars far colder, it also doesn't have air. Or
               | surface water. So all the challenges are at least an
               | order of magnitude harder.
               | 
               | And it's much _much_ further away.
               | 
               | Rhetoric and wishful thinking are not going to give you a
               | better life if you can't deal with the reality of the
               | challenges.
        
               | Tepix wrote:
               | If we really wanted to, i don't see why we couldn't
               | establish a self-sustaining base in Antarctica. Of
               | course, it's forbidden.
        
               | spaetzleesser wrote:
               | Then create one in the Sahara or the Atacana desert at
               | 5000m elevation. Still way easier than Mars.
        
               | mannerheim wrote:
               | They are certainly easier, but how useful are they? A
               | base on Mars will bring down the fuel requirements to
               | exploring and exploiting the belt and outer planets
               | tremendously. Missions that are impossible or
               | uneconomical to do from Earth could be made possible and
               | cheap if launched from Mars.
        
               | ncmncm wrote:
               | Anything that seems easier from Mars is overwhelmingly
               | easier without stopping at Mars first. Even Phobos would
               | be a better choice.
               | 
               | The only thing Mars has going for it is hype.
        
               | spaetzleesser wrote:
               | If you are concerned about a launchpad for other missions
               | the moon is much better. Lower gravity, easy to reach.
        
               | mannerheim wrote:
               | How would you produce fuel and propellant on the Moon?
               | SpaceX plans on producing methane and lox from water and
               | CO2 on Mars.
        
               | ethbr0 wrote:
               | At the end of the day, profit determines reality. And
               | that's where futurists have always screwed up, because
               | profit funds solutions.
               | 
               | Nobody has colonized Antarctica not because it's
               | impossible, but because it's difficult enough and useless
               | enough that we all agreed on a treaty prohibiting it.
               | 
               | In contrast, we constructed the 63 radars (some with
               | bases) of the DEW line in the late 1950s in under 3
               | years, with part of the Air Force's budget. Because it
               | was useful.
               | 
               | Establishing a Mars colony is not impossible, it's just
               | extremely hard. Which means expensive. Which means it
               | needs a justification. Which is what I think the knee-
               | jerk is really about.
               | 
               | And is a fair _opinion_. You may think interplanetary
               | colonization should not be a priority. I think it should.
        
               | pharke wrote:
               | > soil
               | 
               | Both aquaponics and aeroponics provide ways to grow
               | plants without soil. Breeding insects or algae may
               | provide nutrition with very small amounts of mass needing
               | to be transported.
               | 
               | > nuclear reactors
               | 
               | Yes, these are a necessity but we've sent one to
               | Antarctica before and we could send a more modern one to
               | Mars.
               | 
               | > nuclear and other fuels
               | 
               | The good thing about nuclear fuel is that you need a very
               | small amount of it to produce a lot of energy for a long
               | time.
               | 
               | > machinery for every eventuality (including chip fabs)
               | 
               | Colonists by necessity must make do with less and that
               | does mean a lower standard of living and higher mortality
               | but you know what they do it anyways because some things
               | are worth trading comfort and a decade or two of life
               | for. English colonists didn't bring the entire industrial
               | infrastructure with them to the New World. They brought
               | what would fit on the boats and had to make do with what
               | they could create from local resources or do without.
               | They had the benefit of subsequent voyages but I don't
               | think anyone here is imagining colonizing Mars or
               | Antarctica with a single expedition.
               | 
               | > raw materials
               | 
               | Mars (and Antarctica for the most part) do lack anything
               | biological in origin, no oil or wood or crops as
               | feedstock for chemical reactions but there are always
               | alternatives. We usually don't use those alternate
               | sources here because they are too labour or energetically
               | or materially expensive but when they are your only
               | option price and effort become less of a concern.
               | 
               | > all the challenges are at least an order of magnitude
               | harder
               | 
               | No one who is attempting to work towards this is doing it
               | because it is easy. I remember there being a speech about
               | that which ended up with some pretty spectacular results.
        
               | hedora wrote:
               | > _Mars (and Antarctica for the most part) do lack
               | anything biological in origin, no oil or wood or crops as
               | feedstock for chemical reactions but there are always
               | alternatives._
               | 
               | Ignoring energy sources (solvable using by a fission
               | reactor), the entire Earth has a similar feedstock
               | problem as Antarctica. There's plenty of hydrogen and
               | oxygen there. CO2 can be mined from the atmosphere by
               | plants. Nitrogen is the remaining building block of life.
               | At this point, most of the nitrogen in human tissue was
               | extracted from the atmosphere using the Haber-Bosch
               | method (which, roughly speaking, converts atmospheric
               | Nitrogen and energy to fertilizer).
               | 
               | I agree that Antarctica would be an easier (and safer)
               | place to build the first self-sustained "moon base"
        
               | AitchEmArsey wrote:
               | "We go to the moon not because it is easy, but because if
               | we don't then some commie bastards will get there first."
               | 
               | I am all for exploration and science for the sake of
               | science, but any talk of colonies is just wasted breath
               | at this stage. We need to first explore how to live
               | within our means on earth.
        
               | shswkna wrote:
               | Linear Reasoning
        
               | spywaregorilla wrote:
               | Mars is multiple orders of magnitude more difficult to
               | survive on than the Middle East. Its not really
               | comparable at all.
        
               | ethbr0 wrote:
               | I like to think we've improved our technology a few
               | orders of magnitude in the last 1.8 million years.
        
               | spywaregorilla wrote:
               | And so you think you can just mush those two claims
               | together and come to the conclusion that sustaining life
               | on mars must be achievable?
        
               | ethbr0 wrote:
               | Not must be. Is probably achievable, and is worth
               | attempting, even at the cost of lives.
               | 
               | You can argue from either the perspective of futility of
               | attempt (no chance of success) or futility of outcome
               | (success wouldn't be worth it), but I'm pretty convinced
               | both would be weak arguments, both logically and
               | historically.
        
               | spywaregorilla wrote:
               | I'm probably an optimist on Mars travel. I think, with a
               | fuck ton of starships, you could get people living on
               | Mars. But there's some big asterisks on that. You'd more
               | or less have to live in the starships, dependent on
               | shipments from earth, with self sufficiency failing on
               | pretty much every category. Over a very long period, most
               | people would probably die a bit earlier from radiation
               | and dust. Not much would be produced of value. It would
               | cost hundreds of billions of dollars, at least. And
               | interest in it would rapidly decline.
        
               | hedora wrote:
               | Sounds like the early days of Australia. Maybe build a
               | new Botany Bay? (Only half joking.)
        
               | ethbr0 wrote:
               | The suspicion I have about self sufficiency pessimism is
               | that it's an apples to oranges comparison. Are there any
               | modern analogies? As near as I can tell, it hasn't been
               | required after the 16th century, due to access to
               | relatively timely transportation.
               | 
               | And if it hasn't been required, then how are we to look
               | at existing practice and say we're bad at or incapable of
               | it?
        
               | wcarron wrote:
               | > Only one technology matters: that which enables
               | transportation.
               | 
               | Is this tongue-in-cheek? I genuinely hope so.
        
             | subsubzero wrote:
             | agree, extreme temp variations and a toxic atmosphere would
             | make living there very difficult(not to mention the
             | journey!). Much better to try a moon station first as its a
             | few days travel and then compare what went right/wrong and
             | then think about replicating that for mars. Having water on
             | mars does help its case though..
        
       | [deleted]
        
       | darepublic wrote:
       | I feel like there is definitely a trend of astronomy articles low
       | key alluding to or hinting at life on other planets in their
       | titles. Presumably to garner clicks and be bait, but when you
       | read the article invariably it's good old science and no life to
       | be found yet.
        
       | excalibur wrote:
       | If it's the third planet why are they calling it Proxima Centauri
       | d?
        
         | mjh2539 wrote:
         | Maybe 'Proxima Centauri a' refers to the star itself? I'm not
         | sure.
        
           | djokkataja wrote:
           | Yep
           | 
           | https://en.wikipedia.org/wiki/Exoplanet#Nomenclature
        
       | denton-scratch wrote:
       | "Earth-like planet"?
       | 
       | It orbits the star every 5 days; it's a quarter of the earth's
       | mass. It's also a tenth the distance from its star that Mercury
       | is from the Sun. It's earth-like only in that its temperature is
       | consistent with there being liquid water.
        
         | mortehu wrote:
         | "Earth-like" just means terrestrial, as opposed to jovian. It
         | means it has a rocky surface.
        
           | zardo wrote:
           | Terrestrial and rocky are both far better choices to
           | communicate the concept.
        
           | once_inc wrote:
           | Then they should have just called it a rocky planet. Earth-
           | like is a massive misnomer/clickbait here.
        
             | s1artibartfast wrote:
             | It is the term used in planetary science. Not understanding
             | something doesn't mean clickbait
        
               | zardo wrote:
               | Being the accepted term in the field doesn't it make it
               | _not_ click-bait. That just comes down to whether or not
               | using the term in the headline baits people to click.
               | 
               | The abstract refers to it as "sub-Earth", and a "Earth-
               | mass".
        
           | rbanffy wrote:
           | Venus is also classified as Earth like, but it's rocky
           | surface looks more like hell than the mythological
           | descriptions of it. ;-)
        
             | Cthulhu_ wrote:
             | Since we're being a bit pedantic in this thread, the
             | biblical descriptions of hell are limited to darkness and
             | gnashing of teeth.
        
               | rbanffy wrote:
               | I think that the fire and sulphur part is mostly from
               | Muslim tradition. They kind of got close to what Venus
               | is.
        
         | rob74 wrote:
         | Well, Proxima Centauri isn't really "Sun-like" either, so what
         | constitutes an "Earth-like" planet for a different type of star
         | is debatable...
        
         | mcv wrote:
         | Could you please stop ruining cool science journalism headlines
         | with your facts?
        
         | rbanffy wrote:
         | IIRC from other publications, they expect something between .26
         | and 1.1 Earth masses, so it may well be a reasonably big rock.
         | Surface gravity, composition and atmosphere are also big
         | factors in being Earth like - Titan has a lower gravity, but a
         | much thicker atmosphere than Earth.
        
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