[HN Gopher] IAC confirms existence of a Super-earth in the habit...
___________________________________________________________________
IAC confirms existence of a Super-earth in the habitable zone of a
Sun-like Star
Author : ohjeez
Score : 200 points
Date : 2025-01-28 15:09 UTC (7 hours ago)
(HTM) web link (www.iac.es)
(TXT) w3m dump (www.iac.es)
| hmmmcurious1 wrote:
| Helldivers predicted this
| stuckinhell wrote:
| ?
| robotnikman wrote:
| Humans live on a planet called 'Super Earth' in that game
| candyapplecorn wrote:
| FOR SUPER EARTH!!!
| platz wrote:
| It's not in the habitable zone 100% of the time because of its
| eccentric orbit.
| ceejayoz wrote:
| It's not in _our_ habitable zone.
|
| Life on such a planet seems likely to hibernate just like some
| Earth life already does.
| doctoboggan wrote:
| > It's not in our habitable zone.
|
| The habitable zone is defined as the area around a star where
| liquid water could be found, there is no "our" habitable zone
| and "their" habitable zone.
| ceejayoz wrote:
| Parts of our own Earth aren't in the habitable zone, by
| that definition. Even here we get big surprises - undersea
| vents were unexpected oases, microbes miles deep
| underground, microbes living in boiling water in
| Yellowstone...
|
| Not all life in the universe may require liquid water, nor
| require it 24/7. In our own solar system, some planetoids
| _outside_ our supposed habitable zone likely have some
| liquid water - Europa and Enceladus, for example.
| patmorgan23 wrote:
| Do any of those zones actually have life?
|
| The two examples you gave... Include liquid water.
|
| As far as I know there is no life native to the coldest
| parts of the earth that have no liquid water.
|
| It is entirely possible there is some other form of life
| that does not require liquid water, but we have yet to
| discover it.
| ceejayoz wrote:
| > The two examples you gave... Include liquid water.
|
| This specific planet spends half its orbit in said zone.
| Here on Earth, we have creatures like
| https://en.wikipedia.org/wiki/Mudskipper that can survive
| severe dry spells, and fish that can happily freeze sold
| in ice for months.
|
| Europa spends _zero_ time in our solar system 's
| "habitable zone", but because of its conditions, may
| still possess large amounts of liquid water. It's a
| perfect example of why the "zone" may be overly narrowly
| defined, even for Earth-like water-dependent life.
|
| > It is entirely possible there is some other form of
| life that does not require liquid water, but we have yet
| to discover it.
|
| And we certainly won't if we _only_ look in Earth-defined
| "habitable" zones.
| dylan604 wrote:
| You seem to be deliberately trying to pervert the
| definition of habitable zone.
|
| Just because there are regions on a planet in the
| habitable zone that contains ice does not mean it is not
| in the habitable zone. If it were further out beyond the
| habitable zone, there would be no liquid water at the
| surface.
|
| To quote my friend Andy Dufresne, "How can you be so
| obtuse?...Is it deliberate?"
| ceejayoz wrote:
| > You seem to be deliberately trying to pervert the
| definition of habitable zone.
|
| No, I'm saying an Earth-life centric metric is a bit of
| an odd choice when evaluating extrasolar planets.
|
| It's like an African elephant declaring Norway
| uninhabitable.
| pc86 wrote:
| Earth is the only environment in which we've found life,
| so it makes sense to first focus on other Earth-like
| planets. Your point is not without merit but taken to the
| extreme it would be like sending exploratory teams to the
| Mariana Trench to look for un-contacted human tribes.
|
| We have incontrovertible evidence that water + carbon +
| time sometimes equals life. We have no evidence of any
| other non-carbon or non-water chemistries resulting in
| life so why wouldn't we focus on locations potentially
| rich in water and carbon first?
| ceejayoz wrote:
| The first exoplanet detection was in 1992; in my
| lifetime, "there are no planets outside our solar system"
| was roughly as supportable as "there is no life outside
| our solar system" is today.
|
| Here on Earth, we can barely decide if viruses are life
| or not, and discover new things _within our own bodies_
| pretty regularly, despite... a lot of direct access to
| them. (Example:
| https://www.science.org/content/article/it-s-insane-new-
| viru...)
|
| We should be casting a pretty wide net.
| pc86 wrote:
| You seem to be talking past everyone else in this thread
| because nobody has disputed a single thing you've said
| however you're ignoring (perhaps unintentionally) the
| basic statistical reality that if we focus on potentially
| water- and carbon-rich environments we are as a matter of
| course more likely to find life sooner.
| ceejayoz wrote:
| But the "basic statistical reality" is also "there are a
| lot more known/accessible planets outside of the zone in
| which liquid water exists naturally on the surface",
| which leads to a quantity vs quality consideration for
| which we don't have enough information to decide right
| now.
| pc86 wrote:
| Yes but "we don't have enough to decide" means you have
| to lean on the single data point you have, not completely
| ignore it and just try to look everywhere all at once.
| You have to focus your finite resources and "just pick
| something" isn't a reasonable path when there's more
| things to investigate than we could do in 10 lifetimes.
| ceejayoz wrote:
| The correct scientific approach to a sample size of one
| tends to be "not enough information to make a decision".
| ziddoap wrote:
| Lets start our search for helium-based life forms
| immediately!
|
| Or maybe we start with what we know (carbon-based), and
| _keep our minds open_ to other possibilities. Like we do
| now.
| ceejayoz wrote:
| > Or maybe we start with what we know (carbon-based)
|
| But we know more than one thing. One of those things is
| the Fermi paradox - that the universe should
| statistically be _full_ of evidence of life, and yet we
| struggle to find it. That _may_ be evidence we 're making
| the wrong assumptions.
|
| > keep our minds open to other possibilities...
|
| Yes, and I'd argue that means including scenarios like
| Jupiter's moons in our search. (As a bonus, Jupiter-style
| planets, being larger and far from the star, are
| substantially easier to find.)
| jdiff wrote:
| Like you said, the first exoplanet was detected in your
| lifetime.
|
| We haven't even had the chance to fail yet, the Fermi
| paradox is not yet in play when we're considering
| essentially our first move. To extend an analogy from
| further up thread, it'd be like looking in the Mariana
| Trench for un-contacted human tribes after taking a quick
| glance around the neighborhood and deciding there's
| nothing else to be found anywhere else.
| ramblenode wrote:
| Look up "informative vs uninformative prior".
| glenstein wrote:
| There's a meaningful operative definition and you're
| muddying the waters over that definition on the grounds
| that, hey, who knows, maybe it's different somewhere in
| some way.
|
| I just think you're confused if you think that observing
| a specific definition of habitable zone is tantamount to
| a specific denial of that possibility.
| ceejayoz wrote:
| I'm not confused by its definition, I just dislike the
| use of the term. It leads to significant confusion in
| laypeople - "they found a habitable planet!" is something
| I've heard breathlessly repeated multiple times, and "but
| Earth is so perfectly placed, it can't be by chance!"
| used as an argument for creationism.
| throwup238 wrote:
| _> Parts of our own Earth aren 't in the habitable zone,
| by that definition._
|
| What parts would that be? Even the polar caps have huge
| liquid water oceans underneath. Unless you're talking
| about the mantle or molten core, there are no
| uninhabitable areas on earth as per astrobiology (not
| even miles underground).
|
| _> Not all life in the universe may require liquid
| water, nor require it 24 /7._
|
| You might as well be talking about leprechauns and
| unicorns and Horta. Water is the universal solvent and
| has at least five unique properties that are as critical
| to life as carbon's ability to form four chemical bonds.
|
| You're correct that moons experiencing tidal heating can
| contain liquid water, but that's irrelevant to a planet.
| The habitable zone is specifically talking about
| _planets_ (rocky ones at that), not any arbitrary
| satellite. It's a term of art in astronomy, not a
| colloquialism.
| ceejayoz wrote:
| > Unless you're talking about the mantle or molten core,
| there are no uninhabitable areas on earth as per
| astrobiology (not even miles underground).
|
| We've found microbes that can survive at 120 Celsius, -25
| Celsius, very high and very low pH, large amounts of
| ionizing radiation, intense pressures, etc. Habitability
| is a _wide_ range encompasing scenarios not conducive to
| liquid water.
|
| > Water is the universal solvent and has at least five
| unique properties that are as critical to life as
| carbon's ability to form four chemical bonds.
|
| None of that rules out life on other chemistries. It
| makes water+carbon-based life the most likely scenario on
| planets with liquid water, but hardly rules out other
| potential biologies.
|
| > You're correct that moons experiencing tidal heating
| can contain liquid water, but that's irrelevant to a
| planet. The habitable zone is specifically talking about
| planets (rocky ones at that), not any arbitrary
| satellite.
|
| But we should absolutely be looking at planet-sized moons
| with potentially habitable conditions, which we believe
| to be quite common. They are, after all, more common than
| the single "habitable zone" planet even within our own
| system.
| throwup238 wrote:
| Dude, just read the Wikipedia article: https://en.wikiped
| ia.org/wiki/Hypothetical_types_of_biochemi...
|
| It's not impossible, but we've got a ton of evidence why
| it's extremely unlikely. It's a long list including stuff
| like possible quantum transition states enabling
| biochemistry, reactivity with oxygen (the third most
| abundant element), and spectroscopic transparency. It's
| an active area of research that keeps coming up with dead
| ends.
|
| Ammonia and methane are the best candidates but those
| would only be possible at low temperatures that preclude
| lots of other reactions.
| ceejayoz wrote:
| The Wikipedia article supports my point - plenty of smart
| folks think it's at least plausible for alternative
| chemistries to work.
|
| An ammonia-based life form at our stage of exploration is
| probably gonna scoff at the idea of scaldingly hot liquid
| water as a basis for life, too.
|
| > It's an active area of research that keeps coming up
| with dead ends.
|
| So's SETI so far, but I'm not willing to conclude
| extraterrestrial life is impossible just yet.
| throwup238 wrote:
| And none of those smart people have come up with any
| experimental evidence that it's actually possible. No
| equivalent to amino acids or nucleotides or saccharides
| or... the list goes on.
|
| I'm not talking about SETI, I'm talking about basic
| chemistry experiments. There are tons of experiments that
| can spontaneously form amino acids and nucleotides, even
| way outside the parameters normally considered habitable.
| ceejayoz wrote:
| That's similarly true for carbon-based life; abiogenesis
| remains a hypothesis in search of concrete evidence.
| throwup238 wrote:
| There is tons of concrete evidence, you're just ignorant
| of it. Start with Stanley Miller's seminal 1953 paper
| _"Production of Amino Acids Under Possible Primitive
| Earth Conditions"_ and go from there. There's been a
| _lot_ of work on the topic since then, several of which
| have made it to the HN front page.
| ceejayoz wrote:
| I'm aware of the Miller-Urey experiment.
|
| It's only one piece of the puzzle, and we're aided
| significantly in it by knowing what the results are
| _supposed_ to look like.
| throwup238 wrote:
| We absolutely know what it's supposed to look like:
| monomers. Monomers that can form polymers.
|
| The specific chemical details are irrelevant. We have no
| evidence of other monomers that could enable non-water
| based life.
| ceejayoz wrote:
| We find polymers outside of Earth-like conditions.
|
| https://en.wikipedia.org/wiki/Hemoglycin
| throwup238 wrote:
| _> Hemoglycin (previously termed hemolithin) is a space
| polymer that is the first polymer of _amino acids_ found
| in meteorites._
|
| I'm done, have a great day! ( _Monomers_ )
|
| Edit: My apologies for being dismissive. I'd like to get
| into the specifics of why amino acids (amino and
| carboxylic groups specifically) are special, and
| interesting exceptions like hydroxy and alpha-hydroxy
| acids, but I've got to get to work and I could spend an
| entire year explaining the nuances. The deeper you get
| into the details, the more the anthropic principle rears
| its ugly head.
| JumpCrisscross wrote:
| > _ammonia-based life form at our stage of exploration is
| probably gonna scoff at the idea of scaldingly hot liquid
| water_
|
| Ammonia-based life exists within water habitable zones;
| Mars is within our Sun's conservative habitable zone [1].
| (Also, "ammonia boils at 98degC instead of -33degC" at
| "60 atm, for example, which is below the pressures
| available on Jupiter or Venus," meaning "ammonia-based
| life need not necessarily be low-temperature" [2].)
|
| One reason to suspect ammonia-based life is rarer than
| carbon-based life is the universe contains a fifth of the
| nitrogen that it does carbon [3]. (This is why silicon-
| based life is also almost written off.)
|
| [1] https://en.m.wikipedia.org/wiki/Habitable_zone
|
| [2] https://www.daviddarling.info/encyclopedia/A/ammonial
| ife.htm...
|
| [3] https://en.m.wikipedia.org/wiki/Abundance_of_the_chem
| ical_el...
| glenstein wrote:
| >None of that rules out life on other chemistries
|
| Is the upshot of this observation supposed to be that
| PLATO should change its plans and direct its telescope in
| a different direction because it has _more_ promising
| places to look than the habitable zones around stars?
|
| If not, and if you can understand why it's prioritizing
| that, then why do you take this definition of
| habitability to be tantamount to denying the possibility
| of discovering other forms of life? For those
| possibilities to be relevant to a research program, they
| need to be motivated by something more than "gee, hey,
| you never know."
|
| So it's not for lack of reflection on those possibilities
| that we arrive at this operative definition of
| habitability. There are pertinent reasons for moving
| forward with this definition that don't amount to denying
| other boutique possibilities. Construing it that way I
| think is just an uncharitable interpretation.
| Davidzheng wrote:
| How is it clear at all that extraterrestrial life is more
| likely carbon based than not. Is there any evidence other
| than it's the only one we know?
| ziddoap wrote:
| PBS Space Time has a very good & informative episode
| covering this. I'll try to dig it up.
|
| Most elements are missing some key properties that carbon
| has.
|
| Silicon is the next most-likely element, but it's still
| missing out on a few properties that carbon has.
|
| Here:
|
| https://www.pbs.org/video/what-if-alien-life-were-silcon-
| bas...
|
| Or on YouTube:
|
| https://www.youtube.com/watch?v=469chceiiUQ
| connorgutman wrote:
| Regardless of the official definition, the word "habitable"
| is highly subjective. Extremophiles like tardigrades can
| survive being frozen and/or completely dehydrated. A planet
| with an eccentric orbit like this one could hypothetically
| support species capable of entering some form of extreme
| hibernation during part of their year.
| hajola wrote:
| While it's possible for conditions for life to emerge or
| sustain itself to be present beyond the habitable zone
| (e.g. there's likely a subsurface ocean orbiting the
| farthest plant from the Sun on Triton), afawk it is more
| probable that life forms in the habitable zone. That is
| the only one we have a data point for.
| glenstein wrote:
| >Regardless of the official definition, the word
| "habitable" is highly subjective
|
| Well, one constructive way to take it out of the realm of
| subjectivity is to put forward a specific definition.
| ziddoap wrote:
| > _the word "habitable" is highly subjective._
|
| Sure, but not in the context of "habitable zone" which is
| a specific term of art in astrobiology.
| ceejayoz wrote:
| > specific term of art...
|
| And that's fine, but when communicating _outside_ the
| speciality, I 'd really like to see some other term used.
|
| https://www.cjonline.com/story/news/politics/government/2
| 025... for example says "Kansas tuberculosis outbreak is
| now America's largest in recorded history", where
| "recorded history" is apparently the CDC's "term of art"
| for "since 1950", which isn't what a layperson hears.
| ziddoap wrote:
| > _And that 's fine, but when communicating outside the
| speciality, [...]"_
|
| The IAC, where this article is from, is the Instituto de
| Astrofisica de Canarias (literally the "Institute of
| Astrophysics")
|
| That's about as far _into_ the specialty as you can get.
| ceejayoz wrote:
| The IAC is communicating outside the speciality here, via
| a press release.
|
| That's why the article's breadcrumbs say "Home >
| _Outreach_ > News".
|
| We saw the same issue during COVID - scientists talking
| to the general public often talk like scientists instead
| of science _communicators_ , and that causes people to
| misunderstand. Fauci's "no evidence" (yet) masking
| prevents disease incorrectly becomes evidence masking
| _can 't_ prevent disease.
| ziddoap wrote:
| Not many uninterested laypeople are going to be browsing
| the IAC website for astrophysics news. People that _are_
| interested should probably familiarize themselves with
| the terminology commonly used in astrophysics.
|
| Once it makes its way to PBS Space Time, sure, maybe you
| avoid terms of art. Or explain the particular definition
| when it is first introduced.
|
| That's just my opinion anyways. I always try to
| familiarize myself with the common terms of art when
| learning about a new discipline.
| ceejayoz wrote:
| > Not many uninterested laypeople are going to be
| browsing the IAC website for astrophysics news.
|
| But they will get linked to it, or read articles by
| reporters using it as a source without enough domain
| knowledge to make the distinction. I, after all, didn't
| _seek this out_ - it just popped up on the HN home page.
|
| > What seems weird to me is to be interested in a
| discipline, seek out news and conversation about it (from
| university press releases!) but then reject and/or argue
| about any terms of art that are established within that
| discipline.
|
| I think science communication, post-COVID, needs to take
| a serious look at how to better explain things to the
| public. "Habitable zone" is simply one example of it.
| ziddoap wrote:
| I edited part of that out, because I actually do broadly
| agree with you regarding science communication, and
| realized my comment was a bit stronger than I intended.
| Looks like you were quick on the quote!
|
| However, I think there's some serious slack to cut when
| you're viewing an article on the Institute of
| Astrophysics website, compared to reading
| Fox/CBS/whatever.
|
| Edit: In my re-reading of the article, I see they define
| it! I'm no longer sure what all this back and forth is
| even about. " _This orbit places it within the habitable
| zone of the system, _meaning it is at the right distance
| from its star to sustain liquid water on its surface_ "_
| Do you want them to not use the term even when they
| define the term?
| ceejayoz wrote:
| > Do you want them to not use the term even when they
| define the term?
|
| Yes, I do. I think it's a needlessly confusing term to
| use in stuff intended for public consumption.
|
| For a similar example of the issue, I often get radiology
| reports in my healthcare provider's portal. My dad is a
| radiologist and they're still quite scary/bewildering to
| read - they frequently use various terms of art for
| "looks fine and normal" that sound terrifying.
|
| That was all fine when the intended audience was other
| doctors, but these days I can pull them up myself. I at
| least know enough to not freak out and ask my dad; many
| don't.
|
| I don't want to see NBC/BBC/NYT articles using the term,
| and that means being careful with the sources from which
| they receive their info.
| steve_adams_86 wrote:
| Given the mass of the planet, if there's a lot of water
| it's entirely possible there could be oceans which stay
| warm due to a hot core.
| nirav72 wrote:
| Reminds me of the planet inhabited by Arachna spider species
| in Vinge's A Deepness in the sky.
| K0balt wrote:
| This kind of resource variability seems likely to favor the
| development of intelligence, so there's that.
|
| But I m sure we will find that the planet has issues that make
| complex life unlikely, just on a statistical basis.
|
| Simple life seems increasingly likely to propagate through
| panspermia, based on what we find deep inside the crust of our
| planet. Life forms that feed off of radioactive decay
| especially seem promising for panspermia.
|
| I wouldn't be surprised at all if we discovered that for
| habitable zone, earth-like planets , the presence of simple
| life forms deep inside the crust turns out to be the rule
| rather than the exception, at least in our corner of the
| galaxy.
| UltraSane wrote:
| in Vernor Vinge's novel A Deepness in the Sky the alien planet
| freezes for part of the year and the intelligent aliens have
| evolved to survive being frozen and thawed. One group develops
| technology to say unfrozen while their enemies are frozen and
| this gives them a huge advantage.
|
| Great book and I highly recommend it. Also has concepts of
| realistic mind control that is VERY creepy and the ultimate in
| distributed computing based on smart dust.
| dmix wrote:
| How do they evolve when they are frozen part the year before
| evolution?
| rmsaksida wrote:
| Life in that planet evolved to essentially hibernate during
| their long winter. Presumably the processes that resulted
| in the very earliest life forms happened countless times
| until some surfaced that had that feature.
| strictnein wrote:
| > Unlike most planets in the Solar System, HD 20794 d's orbit is
| not circular but elliptical
|
| Kepler's First Law says otherwise.
| ceejayoz wrote:
| It has an eccentricity of 0.40
| (https://en.wikipedia.org/wiki/82_G._Eridani).
|
| That's about twice as eccentric as Pluto/Mercury; Earth's is
| 0.016.
|
| It's a _reasonable_ layperson-friendly summary of the
| situation.
| close04 wrote:
| The orbits of planets in our solar system are quasi-circular,
| with only Mercury (e=0.20) and Mars (e=0.09) being more
| elliptical. Every other planetary orbit in our solar system has
| e<0.05, even 0.00x for Venus or Neptune.
|
| They're not perfect circles but close enough for all practical
| purposes.
| dylan604 wrote:
| If a "humanoid" from this planet visited Earth with 1/6 of their
| normal gravity, would they be a super athlete, or barely
| functional?
| tokai wrote:
| The moons gravity is 1/6 of the Earths. So looking at our moon
| visitors performance, a super earth visitor would probably be
| great at high jump but pretty shaky at anything else.
| gpm wrote:
| I wonder if jumping even makes sense at 6x gravity... maybe
| they would never have learned how to jump at all and always
| keep some limbs in contact with the ground.
|
| Or if "humanoid" even makes sense. Something snake like that
| can spread out the pressure along a longer surface might be
| better. Or at least something with more than two legs.
| josefx wrote:
| What body shape would creatures living at six times the
| gravity even have? Would they be able to jump? Would they
| have a skeleton as we know it?
|
| I would almost go looking at deep sea creatures that have to
| deal with extreme pressures on earth.
| short_sells_poo wrote:
| They might have to be entirely aquatic at that point or
| perhaps have some very exotic skeletal structure that can
| support their weight. Perhaps ball shaped beings who roll
| around instead of any sort of walking? I'm unsure how would
| they deal with a small incline.
|
| Weight lifters are able to lift 6x their body weights, but
| it's not a sort of load that we could profitably exist
| under long term. We'd need to have extremely thick limbs
| and at some point that won't help either because of the
| cross-section vs. weight scaling law. It's also a sort of
| weight where any kind of leverage against a joint will
| generate massive forces. E.g. try catching a 50kg falling
| weight, you are likely to dislocate your joints and/or
| break some bones. And yet 1/6 of that is entirely
| manageable.
| ceejayoz wrote:
| Ever pick up what you thought was gonna be a really heavy box
| and it turned out to be empty, and got briefly thrown off-
| balance? I'd imagine that, but for everything.
| dylan604 wrote:
| Oh good, so it's not just me that happened to!
| upghost wrote:
| I asked a physicist friend about this. At 6x mass, it would
| only be 6x the gravity if it was the same size as Earth.
| Depending on the density, the gravity could actually be weaker
| than Earth!
| dylan604 wrote:
| Yeah, not having the radius/diameter of the planet mentioned
| really hurts understanding the effect of that mass. However,
| I doubt it is like Saturn where it could float in water.
| UltraSane wrote:
| If intelligent life exists on a superearth it would be trapped
| there because rockets wouldn't be able to reach orbit. In fact
| 1.4g seems to be the max that chemical rockets can escape.
| Maybe they could built an electromagnetic launcher on top of a
| absolutely huge ramp.
| shepardrtc wrote:
| Or they would be forced to figure out technology that we
| would consider science-fiction, assuming it's possible. To
| consider our tech as the pinnacle is the wrong approach, I
| think.
|
| Perhaps we've had it too easy here - moderate climate, oil as
| an easy fuel source, and gravity that isn't too oppressive. I
| wonder what technology would arise in a more difficult
| environment, such as this superearth.
| messe wrote:
| Nuclear thermal rockets would also be an option.
| Arubis wrote:
| My second, more intelligent, rational take: goodness, that's
| exciting! I can't wait to see more research as it follows.
|
| My first, drowned-in-doom-news take: can I move there?
| Immediately?
| tonetegeatinst wrote:
| I pray we get star treck replicators.
| fragmede wrote:
| we're a long way from there, but 3d printers are the very
| first step to getting there
| MrLeap wrote:
| I invite you to stay on Earth.
|
| Balance compassion for yourself and others. Finding the balance
| is really hard, maybe impossible to do perfectly, so you have
| to try constantly. When you get close, I think you'll find that
| negativity evaporates in yourself in a way that's infectious to
| those near by you. Take care.
| pc86 wrote:
| The only thing more exhausting than people acting like an
| election instantly makes everything great and the world is now
| going to be amazing is the people acting like it's literally
| the end of the world.
|
| You will not be substantially better or worse off a half-decade
| from now than you would have been in a slightly different
| circumstance.
| myko wrote:
| Honestly a really bad take given the current environment.
| This is the not the thread for it but I'll point out that
| just today funds families around the USA and world require to
| live were pulled out from underneath them, regardless of law.
| I have a child who depends on those funds so it impacts me
| greatly, and I don't know if that child will be around long
| enough without funds for her care.
|
| So please do not minimize what people are going through, it
| may not impact _you_, but many people are negatively impacted
| by the insurrectionist taking over the USA.
| jedberg wrote:
| Tell that to someone who lived in Germany in 1933.
| notpublic wrote:
| Highly recommend listening to In our Times (BBC) episode "The
| Habitability of Planets" that was aired last month.
|
| https://www.bbc.co.uk/programmes/m0025vvd
| wiz21c wrote:
| > HD 20794, a star with a slightly lower mass than the Sun and
| located just 20 light-years away
|
| I'd prefer to hear about interstallar travel news rather than
| DeepSeek ones :-) The pale-blue-dot is really generating anxiety
| :-/
| prewett wrote:
| Check out https://www.centauri-dreams.org/, it's a blog
| dedicated to interstellar travel. It's on hiatus at the moment,
| but there are plenty of back articles to read!
|
| However, I recommend you figure out how to reduce your anxiety,
| because after reading it for a while it will become clear that
| interstellar travel isn't happening any time in the foreseeable
| future. Fortunately, I don't think that a species that
| flourishes from the hot tropics to the freezing arctic is
| likely to be in much existential danger from climate change,
| and even less from the volatile vagaries of politics. (Climate
| change might bring very substantial changes, but escaping off-
| planet isn't going to be _less_ change)
| hajola wrote:
| Next year there is a plan to send a space telescope to L2 with
| the main objective being to search for Earth-like planets around
| Sun-like stars in the habitable zone.
|
| Like Kepler and TESS telescopes it will use the transit method to
| find new exoplanets, but unlike any mission before, it's going to
| look at the same spot in the sky for over a year. Super excited
| to see what data it brings back to us.
|
| The telescope is called PLATO (
| https://en.wikipedia.org/wiki/PLATO_(spacecraft) )
|
| I contributed to the project a few years back, very happy to
| answer any questions.
| fragmede wrote:
| What was your contribution?
| hajola wrote:
| Figuring out the optimal placement of CCDs on Plato's 24(+2)
| cameras. Due to the way CCDs are fabricated, their properties
| vary a bit, they are not identical. For example, they can
| vary how much light they can hold before they become
| saturated. Given the high cost of fabricating these CCDs, and
| the fact that for each camera 4 CCDs are used, and all these
| 4 have to share front-end electronics, it was prudent to
| optimize their grouping to we maximise the dynamic range we
| get. More dynamic range means that we can tell more about the
| planets we find with higher confidence.
| ziddoap wrote:
| > _CCDs_
|
| I think this is "Charge-Coupled Device"?
|
| _" an electronic sensor that converts light to digital
| signals through charges generated by bouncing photons on a
| thin silicon wafer"_
|
| Is that correct? Not familiar with the acronym.
| hajola wrote:
| Yes that's correct.
| UltraSane wrote:
| Yes. In telescopes they use high-end CCDs with really big
| pixels for better light sensitivity and zero dead pixels.
|
| This is a picture of the CCD array for the Gaia space
| observatory that used parallax to measure precise
| distances and slightly less precise angular velocities of
| billions of objects
|
| http://www.bo.astro.it/~altavilla/FTP/GAIA/IMAGES/The%20c
| omp...
| fragmede wrote:
| That's awesome! Are the multiple CCDs because you're taking
| photos in separate colors or something?
| hajola wrote:
| Good question. No, these will essentially be black-white
| "photos". The amount of light is measured. The reason for
| so many CCDs is so that the field of view would be as
| large as possible. A larger field of view enables to look
| at more stars at once. Given that we will be locked into
| looking at one spot for a whole year, it ups our chances
| of spotting something cool if we maximise the number of
| stars we are looking at.
|
| However they won't be photos of planets really. It will
| be countless photos of the same stars over and over
| again, it's just that sometimes they will be slightly
| less bright than other times. Directly imaging exoplanets
| is incredibly difficult, but humans have managed it: http
| s://en.wikipedia.org/wiki/List_of_directly_imaged_exopla.
| ..
| byteknight wrote:
| Do they move the telescope over the year to account for
| movement? How is that calculated? Does this change with being
| closer to planets and their gravitational pull?
|
| Asked from a total moron.
| daveguy wrote:
| Here is the Wikipedia about Lagrange Points (L2 is one of
| these): https://en.m.wikipedia.org/wiki/Lagrange_point
|
| The orbital corrections are minimized at L2, because of the
| relative distance of the moon and other planets vs size. But
| that is what is accounted for in the corrections.
|
| James Webb Telescope is at Sun-Earth L2.
| hajola wrote:
| Yes, it's something that's referred to as pointing stability.
| The telescope will have star trackers to precisely know it's
| relative position - basically you make sure that you see the
| correct stars from where it is placed on the spacecraft. It
| will use reaction wheels to make tiny correction's to its
| position. Imagine you are in a computer chair and trying to
| spin yourself without feet or hands touching anything, just
| by twisting your body. Reaction wheels work on the same
| principle. As Earth completes a year around the Sun, the
| gravitational pull from other solar system bodies is very
| minor on PLATO. That said, keeping a spacecraft in L2 is not
| easy - there is nothing to "orbit".
| UltraSane wrote:
| And when the reaction wheels get saturated they have to
| expend propellant to let them spin down. It is a
| fascinating mechanism.
| Rebelgecko wrote:
| Why is it pointing at the same spot for a year ?
|
| Is it to get a more exhaustive survey single star or can full
| of stars? Or does that help it find smaller/further/different
| planets?
|
| And how do they pick where to point at? Is there a way of
| guessing the likelihood of finding a planet?
| pwatsonwailes wrote:
| Light collection. You want to observe one point for a really
| long time so you get a really good understanding of where the
| light is coming from, the properties of that light, and its
| behavioural patterns.
|
| A lot of the detection is statistics around signals, so the
| better (read more thorough and coherent) your data
| (observations of changes in light), the more confidence you
| can have in your conclusions around what's causing the
| changes (planets with different atmospheres, different
| positions, different sizes and compositions etc...).
| hajola wrote:
| Great questions.
|
| > Is it to get a more exhaustive survey single star or can
| full of stars?
|
| PLATO will look at 100k+ stars at once. And for most we will
| be unlucky to see a transit between PLATO and the star.
| Geometrically it won't align - imagine the star systems being
| in different angles from us. To bring an analogue - Take a
| pack of cards and throw them in the air, and take a quick
| picture while they are sitll in the air - how many cards will
| be facing the camera exactly with their edge. For us to spot
| a transit, the planet has to pass between us and the star. If
| the orbital plane is not parallel to us, we will miss the
| transit. So that's one of the reasons why it helps to look at
| bunch of stars with transit method. We expect that about 1%
| of the orbital planes will be aligned so that we can get
| meaningful data.
|
| > Or does that help it find smaller/further/different
| planets?
|
| Imagine you are trying to find Earth from another solar
| system. The longer you look at our Sun the higher the
| likelihood that Earth will pass between you and the Sun. And
| once you get lucky, and the Earth transits between you and
| the Sun, the brightness of the Sun only dips about 0.01%, so
| that means that in order to find small planets we have to
| have sensitive instruments and little noise, so that the dip
| in brightness can be measured. Furthermore, as the planet
| passes the transit and continues on its orbit, the perceived
| brightness of the star will increase, due to the planet
| reflecting some extra light. Measuring that can gives us some
| rudimentary information about the atmosphere - e.g. if a
| small planet reflects a lot of light back, maybe it's covered
| in clouds or snow.
|
| > And how do they pick where to point at?
|
| There's a whole complicated process to find consensus on
| where to point. Basically they look at spots that have lots
| of stars, and they look what type of stars they are. Here the
| objective is to find planets around Sun-like stars, so they
| would prioritize fields that have more Sun-like stars.
|
| > Is there a way of guessing the likelihood of finding a
| planet?
|
| It seems that some stars are more likely to have planets than
| others.
| exitb wrote:
| How does the 0.01% look in comparison to the natural
| variability of star brightness, due to cycles, spots etc?
| Would that be a concern in terms of false positives? And
| also, given the specific line-up needed for us to see the
| pass, how likely it is for us to be able to observe the
| same planet in front of the star in the following years?
| teraflop wrote:
| Stars do change their brightness in various other ways,
| but the light curve of planetary transit has a very
| characteristic shape. It causes the brightness to dim by
| a small but constant amount, with a (comparatively) very
| short and sharp start and end. A transit causes this
| pattern to occur at precisely regular intervals, and I
| don't think we know of any phenomena related to a star
| itself that would imitate the same effect.
|
| Stars' relative positions generally don't change fast
| enough for the angle from which we observe a transit to
| change significantly. A transit of HD 20794 d is visible
| anywhere within a roughly 0.7-degree wide band. But our
| angular rate of motion with respect to the star HD 20794
| is the same as its rate of motion in our sky, about 0.001
| degrees per year. So the transit will most likely
| continue to be observable for decades or centuries to
| come, depending on exactly how the planet's orbit is
| aligned.
| SJC_Hacker wrote:
| Would it be feasible to place telescopes at other orbital
| inclinations with respect to the sun in order to spot
| transits in stars that aren't within Earth's orbital
| plane ?
| teraflop wrote:
| The orbital inclination relative to our sun doesn't
| really have anything to do with it. In fact, stars that
| are aligned with Earth's orbit are _harder_ to observe,
| because they go behind the sun once a year.
|
| Detecting an extrasolar planetary transit requires us to
| be aligned with _the planet 's_ orbit around its star.
| And since those stars are so far away, you would have to
| travel an immense distance away from our solar system to
| appreciably change the relative angle.
|
| HD 20794 is about 20 light-years away from us, so
| changing our observation angle relative to it by 1 degree
| would require traveling about 0.35 lightyears. Our
| fastest-ever interstellar probe, Voyager 1, would take
| 5000 years to travel that distance.
| hajola wrote:
| Thanks for the clarification. You are absolutely right,
| in my post above I accidentally used the word "parallel"
| that caused the confusion. It wouldn't even be
| practically possible to use PLATO to observe them.
|
| Here's a visual if that's helpful to any reader:
| https://www.researchgate.net/figure/Geometric-
| Probability-fo... .
| tejtm wrote:
| >> Is there a way of guessing the likelihood of finding a
| planet?
|
| > It seems that some stars are more likely to have planets
| than others.
|
| to the best of my knowledge it has yet to be proved that
| any star has no planets.
| hajola wrote:
| Probably not the best choice of words from me there.
| However, there is a positive correlation between a star's
| metallicity and the number of planets a star has.
| dotancohen wrote:
| > Why is it pointing at the same spot for a year?
|
| The transit method requires observing a dip in the brightness
| of a star. Actually - three dips. The first dip indicates -
| but does not prove - the existence of a planet transiting in
| front of the star. The change in intensity, rate of change of
| intensity, and duration of the dip all give us information.
|
| The second dip, if roughly identical to the first dip in
| parameters, gives us the orbital period of the star. So now
| we wait a second period in order to observe the expected...
| Third dip, which confirms the planet if it occurs with the
| same parameters at the expected time.
|
| Though I think that such observations would require at least
| two years, and up to possibly four years, for stars with
| orbits of periods similar to our own. I don't believe that a
| single year is long enough.
| dcminter wrote:
| > Though I think that such observations would require at
| least two years
|
| It _is_ at least two years at least if I 'm understanding
| this0 correctly:
|
| _Observational concept
|
| Ultra-high precision, long (at least two years),
| uninterrupted photometric monitoring in the visible band of
| very large samples of bright (V <=11-13) stars._
|
| 0 https://sci.esa.int/documents/33240/36096/1567260308850-P
| LAT...
| hajola wrote:
| I should have been more clear in my original post. AFAIK
| there are two options on the table - looking at two
| fields, both 2 years OR looking at one field for 3 years
| and then doing "step and stare" for the rest of the
| mission. Step and stare being that they "step" into a new
| field, "stare" at it for some time, and repeat.
| jcgrillo wrote:
| To what extent (if any) will this program be impacted if all
| U.S. federal grant funding is permanently cut? Are there U.S.
| funded components/researchers involved?
| hajola wrote:
| As far as I know it won't be affected at all, the project is
| almost fully funded from the European Space Agency. And it
| will most likely be launched with the European Ariane rocket.
| jcgrillo wrote:
| excellent, thanks.
| bane wrote:
| All the more reason why humanity needs multiple space
| programs.
| labster wrote:
| I'm sure that will come up next year when they privatize
| NASA.
| DiscourseFan wrote:
| You mean when it gets named as a subdivision of SpaceX?
| divbzero wrote:
| How far away PLATO will be from the James Webb Space Telescope?
| How big is the L2 Lagrange point? (i.e., how closely do you
| need to be for an orbit around L2 to be practical?)
| hajola wrote:
| > How big is the L2 Lagrange point? (i.e., how closely do you
| need to be for an orbit around L2 to be practical?)
|
| The L2 point doesn't really have size, and even its location
| isn't stable. It's a mathematical point, and when we say
| "orbit around L2" then that is not fully true either. The
| spacecraft are on what's called "halo orbit" - maybe imagine
| balancing a steel ball (like from a bearing) on a bottle
| that's sideways, it's probably easier to roll and balance the
| ball lenghtways of the bottle, than on rolling it sideways.
| The best analogy I could come up with. You don't want to be
| too close to the L2 point, as then the orbit would be very
| short and less stable, think of it as having a smaller bottle
| - probably harder to balance the steel ball on a smaller
| bottle than a big one.
|
| > How far away PLATO will be from the James Webb Space
| Telescope? Probably on the magnitude of hundreds of thousands
| of kms on average. Interesting question though, hopefully
| they won't get too close :D
| nick3443 wrote:
| What's the typical time scale for a transit? Also, why use
| transits instead of the Doppler method? Has this patch of sky
| been selected based on previous Doppler method star studies?
| Thanks!
| hajola wrote:
| > What's the typical time scale for a transit?
|
| Generally measured in hours, or minutes. For example, if we
| were observing our system with perfect alignment, Earth's
| transit would be about 12 hours, Jupiter's transit around 29
| hours.
|
| > Also, why use transits instead of the Doppler method?
|
| Quantity. PLATO can observe a sizeable portion of the sky at
| once, 100k+ of stars. With Doppler method the quantities are
| smaller + afaik there is a trade-off between number of stars
| being observed and the velocity we can measure. So to find
| Earth-like planets around Sun-like stars, we would likely
| have to go one or a few stars at a time.
|
| > Has this patch of sky been selected based on previous
| Doppler method star studies?
|
| I am not actively involved anymore. So I am not sure if they
| have already picked what part of the sky they PLATO is going
| to be observing. The previous Doppler method (aka as radial-
| velocity or rv method) star studies play a role, not only
| because if there's one planet, there might be more, but also
| because rv gave information about the star. However, keep in
| mind that this is to find new exoplanets, less to find out
| more data about existing ones. Rv will definitely be used
| along side PLATO, to confirm and gather more information
| about exoplanets that PLATO finds.
| stouset wrote:
| > Earth's transit would be about 12 hours, Jupiter's
| transit around 29 hours
|
| ...per year, for Earth; per ~12 years for Jupiter is I
| think what the GP was asking.
|
| This is extremely dependent on the radii of the inner and
| outer limits of the the habitable zone for any given star,
| though, as well as the star's mass.
| nick3443 wrote:
| Both are relevant! Thanks!
| DiogenesKynikos wrote:
| You can find much less massive planets with the transit
| method.
|
| The Doppler method relies on the planet pulling on the star
| to change the star's line-of-sight velocity periodically.
| Because planets are much less massive than stars, the star
| doesn't move much. You can only find massive or close-in
| planets with this method.
|
| The transit method is much more sensitive to small planets
| like the Earth. It's true that the smaller the planet, the
| less of the star's light it blocks, so it's still easier to
| detect large planets than small planets using the transit
| method. However, it's much easier to detect small changes in
| a star's apparent brightness than it is to detect small
| shifts in the star's velocity.
|
| There are a few different viable methods of detecting
| planets. Each has its strengths and weaknesses, and
| astronomers use all of them.
| glomgril wrote:
| Very cool. Got a silly sci-fi question for you. IIUC, with
| current technology it would take on the order of tens of
| thousands of years for a vessel to physically travel to the
| closest known Earth-like planet (correct me if I'm wrong).
|
| So any thoughts on what kinds of hypothetical breakthroughs
| would be needed to make the trip doable in (say) less than a
| human lifetime?
|
| And related, what do you think about the plausibility of the
| [Breakthrough
| Starshot](https://en.wikipedia.org/wiki/Breakthrough_Starshot)
| initiative? Aware of any alternative approaches?
| adamrezich wrote:
| Why does it seem like one of these stories pops up yet again
| every few years?
| hajola wrote:
| It might be because we keep discovering more exoplanets. So far
| we have confirmed 5830 of them (
| https://exoplanetarchive.ipac.caltech.edu/ ).
| adamrezich wrote:
| Why is discovering another headline-worthy then?
| AnimalMuppet wrote:
| "In the habitable zone".
|
| I believe we have some of those, too, but _very_ few.
| Another one is still a bit of a big deal.
| hajola wrote:
| For many reasons. 1 - it might be very unique itself 2 - it
| might be very close to us 3 - it might be orbiting a very
| interesting star, a star type we didn't expect to have that
| planet type or so many planets, or so close, or so far, etc
| 4 - the more exoplanets we discover the more we learn how
| star systems come to be. the more we know how rare ours is,
| how it might have formed, etc. It helps us answer age old
| questions.
| casenmgreen wrote:
| Eccentric orbit.
|
| Too cold is one thing, but too hot I suspect is harder to handle.
| ceejayoz wrote:
| Not sure how "artist's impression" the graphic in the article
| is, but it shows the innermost orbit being _just_ on the edge.
|
| Given we have ice on Mercury right around here, and the fact
| that I have to pressure can stuff like garlic because boiling
| won't kill spores, probably not a dealbreaker.
| https://nssdc.gsfc.nasa.gov/planetary/ice/ice_mercury.html
| hersko wrote:
| And only 20 light-years away...
| tetris11 wrote:
| That's only one generation that would need to be raised on a
| ship
| laxd wrote:
| If we managed to build the ship and if we managed to get it
| to same speed as our fastest space probe, it would take
| around 35000 years.
| bradly wrote:
| At 99% the speed of light it will take the traveler less than
| three years, while 20 years passes on earth. If they then turn
| around they will return to earth, they will arrive aged 6 years
| while 40 years have passed on earth. You can come back younger
| than your children.
| jedberg wrote:
| Which then makes for an interesting moral or ethical dilemma:
| is it ok to embark on such a mission after having children,
| knowing that they will live half a lifetime without you and,
| assuming you left before the age of 34, will be older than
| you when you get back.
| UltraSane wrote:
| It might as well be a billion. Humans in our current form can't
| survive interstellar travel. We would need a far more durable
| substrate.
| ww520 wrote:
| Generational migration can be done.
| parpfish wrote:
| so... not the Barry Diller IAC that owns all the dating apps?
| jillyboel wrote:
| Does it have Super-humans?
| perihelions wrote:
| https://www.aanda.org/articles/aa/full_html/2025/01/aa51769-... (
| _" Revisiting the multi-planetary system of the nearby star HD
| 20794"_)
| vivzkestrel wrote:
| Let me remind you guys that "just 20 light years" = roughly 200
| trillion kms. At the speed of voyager 1, it takes roughly 1600
| yrs to travel 1 trillion kms. 200 trillion kms would take 320,000
| years to reach there. Even if you increased the speed of voyager
| 1 by 10 times, it would still take 32000 years to reach. We
| really need to up the speed by a factor of 10000 before we can
| get anywhere close to human lifetime achievable travel times.
| RobotToaster wrote:
| Even the fastest spacecraft ever made (the parker solar probe)
| "only" went at 692000kph. So 1,000,000,000,000/692,000 =
| 1,445,086 hours, or 164 years.
| foobarian wrote:
| How fast could a ship get going with a RTG powered ion engine
| like AEPS? Rough back of the envelope figures come out to 100
| years to cover 1 light year, or a few thousand to reach 20 ly
| out, which is... nothing like science fiction books but not
| impossible either.
| CrimsonCape wrote:
| Accounting for acceleration and deceleration seems like an
| unspoken obstacle in your timeline. How can a human comfortably
| accelerate or decelerate at a rate greater than 9.8m/s^2 for
| long periods of time? "Hey guys, we will need you to pull 9Gs
| for the next seventy years as your ship slows down to enter a
| stable orbit"
| PartiallyTyped wrote:
| Or alternatively, we make Alcubierre spacecraft work, or we
| move our whole planet system.
|
| All entirely plausible approaches :D
| throwawayk7h wrote:
| Accelerating consistently at 1G (and then -1G for the second
| half), should take 6 years of proper time (from the
| perspective of the traveller) to get there.
| bee_rider wrote:
| Yea, actually the problem is not at all that we'd need too
| much acceleration for the human body. Accelerating at 1g
| for a couple years gets you to preposterous speeds (and we
| don't even need any artificial gravity nonsense!). The
| problem is that accelerating at 1g for years would require
| a ridiculous amount of energy.
| dyauspitr wrote:
| You just need to be constantly accelerating to hit very high
| speeds very quickly. You don't need to pull 9Gs throughout.
| AndrewKemendo wrote:
| I've never understood the idea that humans should be doing
| space exploration. Especially given the proof that robots and
| machines are demonstrably better and more suitable for these
| kind of tasks by such a degree that they dominate off-planet
| sensors-effector combinations.
|
| Making space exploration comfortable for humans instead of
| creating TARS like intelligent machines (possible in our
| lifetimes imo) foundationally limits and constrains the ability
| and scale of exploration.
|
| Seems entirely egoistic and anthropocentric. Is there any
| alternative reason - other than stated - as to why humans
| should be considered the best candidates for these tasks?
| nout wrote:
| If these robots find a good target and make it habitable,
| then you would still need to send humans at some point,
| right? But then you sort of wasted all these thousands of
| years by doing robots first, you might as well send humans
| too.
| bee_rider wrote:
| Humans generally do things out of their own self interest
| (which for a lot of people includes improving the living
| conditions of their descendants). So, if humans aren't going
| to colonize space, we'll either need somebody who... just
| sort of likes colonizing space with robots? Like as a hobby I
| guess?
|
| Or maybe we'll have robots at some point capable of working
| in their own self-interest.
| Fiahil wrote:
| Yes, but that's only a few hours away through hyperspace !
| aaroninsf wrote:
| "Intersecting" the habitable zone isn't the same as "within," I
| find it curious that discussion of the ramifications are far
| down, it seems pretty salient to me...
|
| The idea of an ecosystem hence culture for which a fundamental
| cycle is a year of fallow hibernation followed by a year of
| fertile plenty is quite compelling as a scifi trope though.
|
| Me I'd name the planet Persephone for this reason.
| zombiwoof wrote:
| I'm sure we will see a sign that says "go away stupid humans"
| yapyap wrote:
| cool, ultimately meaningless but cool.
| nicksrose7224 wrote:
| I don't think this is a good take. Discovery & science are
| inherently meaningful even if the applications are not
| immediately felt. Nuclear magnetic resonance (NMR) was
| discovered in 1938, but there was no obvious applicability of
| it to everyday life. In 1971, 33 years later, Paul Lauterbur
| used it to develop the first MRI
| pmayrgundter wrote:
| Meanwhile on Earth, UAP disclosure is kicking into full swing
|
| How long until HN community picks up interest
| asdfman123 wrote:
| Ok, when's the next flight out?
| robertlagrant wrote:
| The existence of the Super-earth was not directly observed, but
| was instead inferred by the gravitational lensing of all the
| democracy[0] being spread in a sphere around the planet.
|
| [0] https://helldivers.fandom.com/wiki/Super_Earth
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