[HN Gopher] If the moon were only 1 pixel: A tediously accurate ...
       ___________________________________________________________________
        
       If the moon were only 1 pixel: A tediously accurate solar system
       model (2014)
        
       Author : sdoering
       Score  : 858 points
       Date   : 2025-06-13 08:40 UTC (1 days ago)
        
 (HTM) web link (joshworth.com)
 (TXT) w3m dump (joshworth.com)
        
       | andersco wrote:
       | Still an extraordinary experience after all these years and
       | possibly the best use of horizontal scrolling I've seen. Lots of
       | previous discussions and posts on HN:
       | https://hn.algolia.com/?q=if+moon+only+1+pixel
        
         | IggleSniggle wrote:
         | It's very very good! I thought this one hit hard though, I
         | assume inspired by the moon = 1-pixel viz.
         | 
         | https://hmijail.github.io/1-pixel-wealth/
        
           | zurfer wrote:
           | that's a great share, I feel like it would also benefit from
           | setting the "speed of light", as something like median
           | average yearly income.
        
           | arrowsmith wrote:
           | This is great, but it needs an update: wealth inequality is
           | even higher today than it was when that site was created.
           | 
           | E.g. it gives Jeff Bezos's net worth as $139 billion, but
           | today it's $228 billion.
        
           | athenot wrote:
           | On the same note: https://xkcd.com/980/ (from 2011 when Bezos
           | "only" had $18b)
        
       | amelius wrote:
       | Make sure you press the "c" button in the bottom right.
       | 
       | Light is incredibly slow, and everything seems out of reach.
       | 
       | I think we'll have a holodeck before we reach another star. And
       | maybe that'll be enough.
        
         | beklein wrote:
         | Maybe light's insanely fast and space is just huge. It's all
         | relative ;)
        
           | isolli wrote:
           | I would say they're two sides of the same coin. The time it
           | takes for light to travel the universe (which makes
           | communication even with nearby stars essentially impossible)
           | is what makes the universe huge.
        
             | neuroelectron wrote:
             | Luckily FTL communication isn't actually impossible and
             | special relativity only applies to energy and mass.
        
               | krapp wrote:
               | FTL communication is actually impossible, what are you
               | talking about?
        
               | jordigh wrote:
               | I can't tell if you're joking or if you know something
               | nobody else does.
               | 
               | As far as I know, anything going faster than the speed of
               | causality violates causality. So what are you talking
               | about?
        
               | ClumsyPilot wrote:
               | > violates causality
               | 
               | But we don't know that casualty is a law of physics, do
               | we?
        
               | IAmBroom wrote:
               | Only inasmuch as we don't know that gravity and the
               | Strong Nuclear Force aren't.
        
               | neuroelectron wrote:
               | Don't conflate causality and special relativity.
               | 
               | SR breaks down at both ends of the spectrum, at the event
               | horizon of black holes and in Bose Einstein condensates.
               | That proves that it is an emergent property of
               | observations, statistical behavior of decoherent systems,
               | and not a universal law.
        
         | munksbeer wrote:
         | > Light is incredibly slow, and everything seems out of reach.
         | 
         | Yes, agreed. I find it a little depressing. An unimaginably
         | huge universe, tantalisingly there, but completely out of
         | reach.
        
           | once_inc wrote:
           | Assuming our models of the universe are correct, and faster
           | than light travel is impossible. There are very strong
           | reasons to believe this, but perhaps we can cheat by
           | stretching and compressing space around us.
        
           | nurettin wrote:
           | Meh, most of it is just more of the same thing. I'd rather
           | play with a paper plane than float in space.
        
           | sheepscreek wrote:
           | It's not the destination, it's the journey :)
        
             | ant6n wrote:
             | 10,000 years of empty space to get to the next solar
             | system. Exciting.
        
               | dylan604 wrote:
               | Plenty of time for reflection on one's choices in life
               | that put them in that situation.
        
               | ant6n wrote:
               | Especially generation 143 of 330, they can definitely
               | spend their whole life on that reflection.
        
               | literalAardvark wrote:
               | Speaking of which, Peter Watts' Sunflower Series has a
               | great and short enough hard-ish scifi story about just
               | such a ship.
        
               | sheepscreek wrote:
               | Not with light speed travel. At even 1% the speed of
               | light, the travel time diminishes significantly:
               | 
               | - Titan, Io and Ganymede are only 2.5 days away - Pluto
               | is about 23 days
               | 
               | Edit: Even at such speeds, we still can't visit a nearby
               | star system in a reasonable time-frame. Oh well.
        
               | Reubachi wrote:
               | As time passes, the universe is expanding infinitely in
               | every direction from every point.
               | 
               | Even if we could travel at 1 percent the speed of light,
               | the "destination" would be inflating away from us at much
               | greater relatavistic speed.
               | 
               | To your point, this is less an issue with solar or extra
               | solar objects.
        
               | ToValueFunfetti wrote:
               | Doesn't this depend on the initial distance to the
               | destination? I'm thinking you have to be going ~140M
               | light-years for cosmic expansion to exceed 1%c, and
               | Proxima Centauri is only ~4 light-years away
        
               | Sharlin wrote:
               | Traveling at .1c within the solar system wouldn't really
               | be feasible due to the need to accelerate and decelerate.
               | Not for meatbag ships anyway.
        
               | ryandrake wrote:
               | There's nothing about 0.1c or even 0.999c travel that's
               | detrimental to meatbags. They would both feel exactly the
               | same to the traveler. If your (for now) imaginary rocket
               | could accelerate at a constant, gentle 1G, you could
               | reach 0.1c in about a month (traveler's time), and you
               | could reach 0.999c in about 44 months. Building and
               | fueling such a rocket is the hard part.
        
               | Sharlin wrote:
               | My point was that the GP talked about flight times
               | assuming instantaneous acceleration and deceleration.
               | Also, 1G of acceleration sustained over a month is more
               | or less impossible for meatbag-sized spacecraft,
               | _especially_ if you need to also accelerate all the fuel
               | you'll need to decelerate. The rocket equation is simply
               | way too brutal. Something like nuclear pulse propulsion
               | might come close. Or antimatter propulsion if we'll ever
               | be able to create and store entire moles worth of
               | antimatter.
        
               | ToValueFunfetti wrote:
               | It depends on how you define the bounds of the Solar
               | System, but eg. a flight from Pluto at its most distant
               | to the same distance on the opposite side of the sun that
               | hits .1C at peak needs ~5G for the entire duration. And
               | it seems quite wasteful to bother getting up to speed
               | before immediately reversing the acceleration.
               | 
               | If you're travelling between points in the Oort Cloud, 1G
               | should be more than sufficient to hit .1c on the trip.
        
               | PartiallyTyped wrote:
               | We can instead happily drive our solar system in a
               | different direction by nudging the sun.
               | 
               | At this point in humanity's history, I think that's more
               | feasible than high speed traveling.
        
           | raxxorraxor wrote:
           | Not out of reach if you get very close to light speed. Time
           | would advance very slowly for you, so counterintuitively it
           | is possible to travel 5000ly in your life time.
           | 
           | Although for everyone else at least 5000 years will pass, so
           | better say goodbye to family and friend.
           | 
           | Hm, not sure if that is really less depressing...
           | 
           | Also light isn't slow. A photon instantly travels to the end
           | of time and yet it still takes a few minutes from the surface
           | of the sun to us. Or about 100000 years from the center of
           | the sun to its surface.
        
             | amne wrote:
             | How would that feel as a traveler? Does all motion slow
             | down to a crawl, all sub-atomic particles just "freeze" and
             | essentially your thoughts and body aging too? So it would
             | seem like you got there in an instant?
             | 
             | For sure you're not just sitting there watching people get
             | born, live and die in second and shrugging your shoulders.
        
               | Sharlin wrote:
               | You'd feel nothing out of the ordinary whatsoever. The
               | starscape outside the ship would look strange though,
               | shrinking into a small, blueshifted patch of sky straight
               | ahead, while stars behind you would redshift out of the
               | visible range. Everything moving at very low speeds
               | relative to you would indeed appear to happen really
               | fast.
        
               | amelius wrote:
               | What are the chances of hitting a small meteorite or part
               | of it, traveling now at relativistic speeds wrt you?
        
               | kqr wrote:
               | Extremely low. Space is very empty.
        
               | brazzy wrote:
               | But it's also very _big_ , and GP doesn't even specify
               | how far of a trip they're asking about nor how small a
               | meteorite.
               | 
               | "Extremely" and "very" don't cut it here. This is beyond
               | the human ability to guess. You'd actually do at least
               | some back-of-the-napkin math to give a real answer, and
               | with a far enough trip, the answer may well become
               | "Almost 100%".
        
               | wat10000 wrote:
               | And at a high enough speed, the impacts from the ~1
               | hydrogen atom per cm^3 in interstellar space become a
               | major problem.
        
               | amelius wrote:
               | How far a trip: maybe start with the nearest star.
        
               | jandrese wrote:
               | It's one of those cases where you have very small numbers
               | multiplied by very large ones. The actual risk is hard to
               | intuit because there are so many orders of magnitude
               | involved in both directions.
               | 
               | In any case it's probably a moot concern as long as we
               | are living under the twin tyrannies of Newtons Third Law
               | and the Rocket Equation. Building a rocket that can
               | accelerate constantly and noticeably for weeks, months,
               | or even years on end in order to accelerate up to a
               | velocity where Relativity starts to matter requires an
               | absurdly large rocket. Like converting the mass of
               | Jupiter into rocket fuel to make it to the next habitable
               | solar system in a couple of centuries level of craziness.
        
               | Sharlin wrote:
               | Micrometer-scale dust particles would in fact hit you all
               | the time. And they'd absolutely mess up your ship over
               | time without a lot of shielding.
        
               | TheOtherHobbes wrote:
               | There's about one particle of dust per million cubic
               | metres. c is about 300 million metres/second. So even at
               | 0.5c that's still a lot of particle collisions per
               | second, each having significant kinetic energy.
               | 
               | Basically it would be like flying through explosive
               | sandpaper. Each dust particle would be reduced to plasma,
               | which creates problems of its own.
               | 
               | If you're accelerating there's also the Unruh Effect,
               | which will raise the perceived temperature. By a lot.
               | 
               | There's no way to make this work with any kind of
               | engineering we know about today.
        
               | southernplaces7 wrote:
               | The Unruh effect is theoretical, and no evidence at all
               | has ever been found that it's real. It literally exists
               | as nothing more than a hypothetical mathematical model,
               | that also happens to be debated by others who know enough
               | to effectively debate it, and disagree.
        
               | Sharlin wrote:
               | Micrometer-scale specks of dust would hit you like they
               | were armor piercing tank gun rounds. The usual shielding
               | proposed is ice. Lots of ice.
        
               | folli wrote:
               | Why ice?
        
               | Sharlin wrote:
               | Mostly that it's plentiful, ablative, expendable, plus
               | good radiation shielding (yeah, cosmic ray protons are
               | really going to mess things up at relativistic speeds too
               | unless there's enough mass to stop them).
        
               | rnjesus wrote:
               | zero if you hit that spice first
        
               | seanw444 wrote:
               | If the light behind you redshifts out of the visible
               | spectrum, would the light in front of you blueshift into
               | dangerous territory? X-rays, gamma rays, etc?
        
               | IAmBroom wrote:
               | Yes. To some degree.
        
               | doph wrote:
               | Yes, and this provides a nice intuition about the
               | relation of wavelength to energy. But x and g wavelengths
               | are several oom shorter than visible light, so you'd have
               | to be traveling at very close to c to experience that
               | amount of Doppler shift.
        
             | thombat wrote:
             | But unless you have a way of slowing down again you'll
             | never see anything of your destination, just the briefest
             | of flares of light as you sail past. And if you do have a
             | way that involves anything like physics that we recognise,
             | you've brought along a huge rest mass that then got
             | accelerated to near light speed. Probably your civilization
             | needs to be approaching Kardashev Level 2 to pull this off.
        
             | causal wrote:
             | Yeah if you have a body that can tolerate sudden jumps
             | between reference frames you could pretty much explore the
             | entire galaxy trivially, so long as you don't mind that few
             | places will stay the same long enough to visit twice.
        
               | ryandrake wrote:
               | You wouldn't need a sudden jump. If you had a rocket that
               | accelerated at a pleasant 1G forever, you could reach and
               | stop at the center of the milky way in about 20 (your
               | time) years, and you could reach and stop at the
               | Andromeda galaxy in about 28 years. Play around with some
               | of the online space travel relativity calculators--it's
               | wild!
               | 
               | Of course building and fueling such a rocket is what's
               | totally out of reach.
        
               | TimTheTinker wrote:
               | > Of course building and fueling such a rocket is what's
               | totally out of reach.
               | 
               | We'd need a device that could efficiently transform
               | several kg of matter to photons.
        
               | widforss wrote:
               | And back?
        
               | lukan wrote:
               | Also some kind of a energy shield. Space is pretty empty,
               | but if you go fast enough, you will still hit lots of non
               | empty space.
        
               | aledalgrande wrote:
               | Is there drag in space? I.e. would you need increasing
               | energy to accelerate at a constant rate as the speed goes
               | up?
        
               | dmoy wrote:
               | I guess one assumes that whatever system prevents you
               | from getting hulled by space dust also removes the drag
               | from the equation?
        
               | ryandrake wrote:
               | With a traditional rocket, I believe you'd need
               | decreasing energy to maintain the same acceleration as
               | the flight progressed, since you are carrying along with
               | you and burning the fuel, and so the total mass (payload
               | + fuel) that needs to be accelerated is constantly
               | decreasing.
               | 
               | Of course there's the pesky problem that for every N kg
               | of mass you want to accelerate at 1G for that kind of a
               | trip, you're probably going to need somewhere on the
               | order of N billion kg of fuel to burn.
        
             | mock-possum wrote:
             | That doesn't make sense - if you were traveling at the
             | speed of light, it would take you 5000 years to travel
             | 5000ly - longer if you were just 'very close' to C. Time
             | wouldn't advance slowly for you, it wouldn't advance
             | perceptively different at all - you'd still live every
             | second of those 5000 years.
        
               | ghosty141 wrote:
               | I dont think you are right. Light for example doesnt
               | perceive time at all. From the photons point of view it
               | never aged even a microsecond while it traveled
               | lightyears. Time is relative too so from our POV 1 year
               | passed when a photon traveled 1 ly, but for the photon no
               | time passed.
        
               | zwily wrote:
               | Read up on time dilation and special relativity. Time
               | absolutely does pass slower for you as you accelerate.
        
               | IAmBroom wrote:
               | You two are talking about different meanings of "time".
               | 
               | Traveling 5,000 LY at 0.5 c will cause you the spaceship
               | pilot to age 20,000 years. It's non-relativistic, inside
               | that inertial frame. Clock second hands still sweep slow
               | but noticeable circles.
               | 
               | Meanwhile, everyone outside of the spaceship is happening
               | FAST, by your observations. You'll see stars turn red and
               | go supernova.
        
               | mr_toad wrote:
               | The journey will take 10,000 years for an external
               | stationary observer and about 8695 years for the pilot.
        
             | danudey wrote:
             | It depends on acceleration though. If acceleration and
             | deceleration take long enough, it could take an entire
             | generation to get up to a fast enough speed that
             | relativistic effects make any difference, and another
             | generation to slow down enough to interact with anything
             | you might see.
             | 
             | Plus if you're traveling at near light speed, running into
             | any matter at all would be pretty devastating for whatever
             | craft you're in.
             | 
             | Edit: someone further down claimed that the math says that
             | accelerating at 1G would get you to 0.1c in a month, so
             | that's actually not that bad all in all. I still maintain
             | that hitting any matter at those speeds might be
             | unpleasant.
        
               | mr_toad wrote:
               | > that accelerating at 1G would get you to 0.1c in a
               | month
               | 
               | Minor problem is that we don't have any technology that's
               | close to capable of that. And at 0.1c relativistic
               | effects are barely noticeable.
        
             | eslaught wrote:
             | One thing I've always wondered is what fraction of c is
             | actually realistically achievable with current
             | technologies? (Maybe with scenarios for manned/unmanned
             | spacecraft.)
             | 
             | Like are we at 0.1% or 0.01% or more orders of magnitude
             | off?
        
               | Scarblac wrote:
               | According to the first Google hit,
               | https://scitechdaily.com/nasas-parker-solar-probe-the-
               | fastes... , the fastest we've made so far went 430k mph
               | (falling towards the sun), or about 0.064% of c. Good
               | guess.
        
               | anon_cow1111 wrote:
               | We have a number! Around 0.1c maximum and unsurprisingly
               | it involves using nuclear bombs to push yourself.
               | 
               | https://en.wikipedia.org/wiki/Project_Orion_(nuclear_prop
               | uls...
        
               | btilly wrote:
               | If you enjoy such questions, I highly recommend
               | https://www.amazon.com/Indistinguishable-Magic-Robert-L-
               | Forw....
               | 
               | The best speed for interstellar travel with technologies
               | that current theory says should be within our reach can
               | be achieved with a vehicle with a light sail pushed by a
               | giant laser, that is powered by solar power. There is
               | even a way to brake it when it reaches the target star. I
               | forget what the predicted velocity was though.
               | 
               | This technology is basically the same as one that the
               | Moties developed in the story, _The Mote in God 's Eye_.
        
               | DiggyJohnson wrote:
               | Slow down by pulling on the fishing line tied to the back
               | of it, carefully.
        
               | btilly wrote:
               | It slows down by releasing a large light sail in front of
               | it, designed to reflect light back to a much smaller
               | light sail behind it. The laser then pushes the large
               | sail away, and as the sail goes it pushes the smaller
               | sail (and ship) back. This leaves the ship at moderate
               | speed relative to the new star, and a large sail
               | traveling very, very quickly beyond it.
               | 
               | We do not yet have this technology. But we can show that
               | it is plausible.
        
             | nilamo wrote:
             | > Hm, not sure if that is really less depressing...
             | 
             | A starship capable of such a journey is surely large enough
             | to bring all your friends and family along, colony-ship
             | style.
        
               | tanewishly wrote:
               | We're already on that starship. Our engine is about 8
               | lightminutes away. All we need is to figure out how to
               | steer this thing - and how to not wreck it while en
               | route.
        
               | lukan wrote:
               | I would prefer the concept of people building an
               | artificial planet/asteroid/spaceship for a starship,
               | instead of messing with our star system. But luckily that
               | debate is some years away and currently we cannot even
               | figure out, how to deal with some increased CO2 levels.
        
             | chrisweekly wrote:
             | > _" A photon instantly travels to the end of time"_
             | 
             | Please explain this. TIA
        
               | tridentboy wrote:
               | First set gamma as being 1/sqrt(1-v^2/c^2), with "c"
               | being the speed of light. The factor for time dilation
               | and distance contraction in special relativity is gamma
               | and 1/gamma respectively.
               | 
               | That means that when you get to speeds equal to c, your
               | time runs infinitely slower and the distances are
               | infinitely shorter. So if your clock is infinitely
               | slower, so every travel at "c" speeds means that no time
               | passes for you. And if your distances are infinitely
               | shorter, all travels at "c" speeds cover any distance as
               | immediate. So you could reach every point of the universe
               | as if it was immediately closer and in no time at all.
               | 
               | So in the frame of reference of the photon, the moment it
               | is created it has already reached its destination, be it
               | wherever it is on the universe.
               | 
               | Of course we can never reach "c" as beings with mass, but
               | we can get closer to that. So for example if you get to
               | 99.99999999999999% of the speed of light, you could
               | travel a distance of 54,794,520 ly and only one year
               | would pass to you, while 54,794,520 years would pass on
               | earth.
        
               | chrisweekly wrote:
               | thanks, great explanation
        
               | dbetteridge wrote:
               | Follow up question from someone who's mostly forgotten
               | his university physics.
               | 
               | Do photons actually exist, in the traditional sense of
               | physical matter.
               | 
               | Or are they just a convenient short hand to describe the
               | transfer of energy via waves in the fabric or space time,
               | if they dont experience the universe when passing through
               | it but only when interacting with matter and matters
               | "dents" in space-time.
        
               | svachalek wrote:
               | As a non-physicist, my understanding is that they
               | actually exist, but can't be thought of as flying around
               | like ping pong balls. I think it's one of those things
               | that comes down to interpretation though, where the math
               | is very clear but how you think of what it "means" lies
               | beyond science.
        
           | gwbas1c wrote:
           | It makes me wonder what kind of "life" could perform
           | interstellar travel? I used to imagine a spaceship being
           | alive, with people inside being analogous to "cells" in a
           | multicellular organism.
           | 
           | Perhaps this is really how AI achieves consciousness?
        
             | kqr wrote:
             | https://en.m.wikipedia.org/wiki/Generation_ship
        
               | TheOtherHobbes wrote:
               | To make a generation ship work you have to build a self-
               | contained ecology that is stable and self-repairing,
               | inside mechanical and software systems that are fault
               | tolerant and either extremely redundant or self-
               | repairing, run by a political and social system that is
               | also fault-tolerant and self-repairing.
               | 
               | We know how to do exactly zero of those things.
        
               | danudey wrote:
               | There's a CRPG I've been meaning to play where this is
               | basically the plot; there was a generation ship, it was
               | heading towards some planet or another, but the social
               | and political structure on the ship broke down at some
               | point and now there's no one actually in charge, the ship
               | is getting run down, and they probably blew past their
               | destination a hundred years ago if they were even still
               | on course at all.
               | 
               | I remember someone pointing out that a generation ship
               | could be problematic because you have one generation who
               | decides to launch this expedition but will never see the
               | end, multiple generations who didn't choose this life and
               | won't get to see the benefits, and then one generation
               | who actually gets to the planet but might not even want
               | to be there. Without some kind of cryogenic sleep or
               | relativistic speeds the whole thing might fall apart just
               | because most of the people involved "didn't sign up for
               | this" but they have to toil away anyway for someone else
               | to benefit from it.
        
               | datameta wrote:
               | What of the "just so" attitude of a child growing up?
               | Everything is taken at face value, there is no
               | comparison, only stories (unless you have a catalogue of
               | 30EB of 8K earth footage or something to that effect for
               | them to fawn over). They don't have the reference frame
               | for other situations for a while, perhaps long enough to
               | not be able to see things differently?
               | 
               | This makes me think of multi-generational migrations
               | north out of Africa. There's only so much that can be
               | passed orally losslessly. Eventually the group in north
               | siberia after 20K years doesn't see living any other way.
        
               | silverquiet wrote:
               | > I remember someone pointing out that a generation ship
               | could be problematic because you have one generation who
               | decides to launch this expedition but will never see the
               | end, multiple generations who didn't choose this life and
               | won't get to see the benefits, and then one generation
               | who actually gets to the planet but might not even want
               | to be there.
               | 
               | That isn't really different from the way things are now.
               | We are, in fact, traveling through the galaxy for many
               | generations and none of us signed up for it. We just
               | happen to be on a largeish ship and have no destination.
        
               | jandrese wrote:
               | More to the point the ship needs to be absolutely self
               | sufficient, it can't even use solar power and has no
               | access to outside mass whatsoever. But if you have a ship
               | like this you could build an orbital habitat using the
               | same technology, and it would be much much easier to
               | build since it doesn't have to accelerate, can use solar
               | power, and has access to the rest of the resources of a
               | solar system.
               | 
               | If you have all of this why would you go to the enormous
               | extra effort to move the habitat to a different solar
               | system? Even if your civilization is so old that the star
               | is a dim brown dwarf that's still plenty of energy for
               | day to day life.
        
               | gwbas1c wrote:
               | > run by a political and social system that is also
               | fault-tolerant and self-repairing
               | 
               | That's the point of the AI; it would generally replace
               | that.
        
               | tanewishly wrote:
               | Well, to be frank, we currently have such a ship, but
               | we're doing quite a lot to disrupt its capability of
               | sustaining human life.
               | 
               | Of course, even if we stopped doing that, we'd need to
               | figure out how to visit another place if our ship is
               | passing close by. That also seems to pose a problem: both
               | Voyagers are barely out of the exhaust fumes of our
               | ship's motor, and getting so far took ~40 years.
        
             | mr_toad wrote:
             | > It makes me wonder what kind of "life" could perform
             | interstellar travel?
             | 
             | That's essentially the premise of Project Hail Mary. Good
             | book.
        
               | southernplaces7 wrote:
               | It's a wonderfully entertaining book and for that reason
               | I loved it, but Andy Weir really, really glosses over and
               | hand-waves away all kinds of other difficulties for so
               | quickly and easily building a ship that can travel at
               | nearly the speed of light.
               | 
               | He basically just has it work because the fuel
               | difficulties are solved and bam, the main character can
               | zip around nearby start systems at close to perfect C on
               | a ship built with little more than our current 21st
               | century technology. Fun, but not even in the most basic
               | way an attempt at presenting any science seriously.
               | 
               | What makes it more amusing is that for many other parts
               | of the main drama, he puts a lot of effort into making
               | the descriptions and scenarios seem as realistic and
               | science-rich as you could like. I suspect a lot of
               | entertaining word salad there too though.
        
           | UltraSane wrote:
           | Not if you are an immortal AI or uploaded human.
        
         | barrenko wrote:
         | I really thought hitting "light speed" would just zoom it all
         | in a minute, but nope... So much for my physics preconceptions.
        
           | pdpi wrote:
           | > would just zoom it all in a minute,
           | 
           | The Earth is about 8 light-minutes away from the Sun :)
        
             | barrenko wrote:
             | I am not liking this fact.
        
               | justusthane wrote:
               | The sun could have exploded seven and a half minutes ago
               | and we'd have no idea! Enjoy the next 30 seconds of your
               | life.
        
           | scraft wrote:
           | Well, if you were traveling at light speed you could move
           | anywhere in the universe instantly. If you are an observer on
           | earth, watching an object move away from you at the speed of
           | light, then it will take a very long time to traverse the
           | tiniest regions of the universe.
        
             | Reubachi wrote:
             | Er, "instant" here is "relativistic instant."
             | 
             | even in a vaccum, light speed travel from the travelers POV
             | still takes time, and said traveler would perceive time
             | passing exactly as occurring in that local space. But yes
             | you're totally correct, the observer on earth would in this
             | time see only the briefest part of my journey's trail due
             | to light from my journey taking "exponentially" longer to
             | travel back to the observer.
        
         | uncircle wrote:
         | True but doesn't matter how slow light is. The closest to c
         | your speed is, the shortest the time you experience on board of
         | the space ship. At light speed, space and time cease to exist.
         | You reach destination instantly.
         | 
         | So the goal is to create engines that can take us close to
         | light speed. Then the issue is braking (spacetime expands as
         | you slow down...)
        
         | thrance wrote:
         | If you travel at relativistic speeds, your trip will appear far
         | shorter to you than to those that stayed on Earth.
         | 
         | With a ship able to accelerate at 1G continuously, you can be
         | at the edge of the observable universe in <50 subjective years
         | [1].
         | 
         | [1]
         | https://www.reddit.com/r/dataisbeautiful/comments/s4tbry/oc_...
        
           | sestep wrote:
           | Naive question: is accelerating at 1G continuously within the
           | range of what we consider possible?
        
             | Vvector wrote:
             | It's a simple question of weight ratios.
        
             | thrance wrote:
             | Not naive at all. With chemical rockets we can only sustain
             | 1G for a few minutes, so it won't do at all for
             | interstellar flights.
             | 
             | There is a known way to achieve 100% fuel efficiency:
             | antimatter. By storing equal parts matter and antimatter,
             | you can fuse them to propel your spacecraft. It's unknown
             | wether or not this kind of engine can actually be made.
             | 
             | Alternatively, and even more far-fetched, you could onboard
             | a small singularity. Dumping anything into it will result
             | in it being turned to pure energy at 100% efficiency,
             | through Hawking's radiations. The smallest the singularity,
             | the fastest it radiates, meaning you can sort of control
             | the output. You can create singularities with very large
             | particle colliders.
             | 
             | With 100% fuel efficiency you can probably sustain 1G for
             | long enough to reach the nearest stars. You would need a
             | very large spacecraft (on the order of kilometers) for a
             | comparatively very small payload. And it would arrive
             | completely empty at its destination, meaning no turning
             | back. I think I saw someone do the math, but can't find it
             | anymore.
             | 
             | Anyway, there are other difficulties. Travelling at .99c
             | means tiny space dust now becomes very dangerous. So does
             | radiations, all made extremely energetic by the Doppler
             | effect.
             | 
             | On the plus side, continous 1G means you have artifical
             | gravity for the whole trip.
        
             | Reubachi wrote:
             | Amazingly, yes, in a few ways (the mechanics are possible).
             | But no in as many ways. (Fuel, sustainability, tracking)
             | 
             | The greater barrier is that the nature of the expansion of
             | the universe prevents any real interstellar travel that has
             | a "destination" in mind. Of course we might have some "FTL"
             | or "near light speed" travel in futre, but if the universe
             | is expanding infintely from every point in space at light
             | speed, how could we ever "catch up" to objects we see even
             | now?
        
               | brazzy wrote:
               | This is not true. Expansion does not affect
               | gravitationally bound structures. Our galaxy, and even
               | the other galaxies in our local cluster, will stay in
               | reach.
               | 
               | Source: https://www.reddit.com/r/askscience/comments/sr7f
               | uo/is_there...
        
               | jandrese wrote:
               | If your travel involves the Rocket Equation the answer is
               | no. If you are limited by the speed of light and the
               | lifetime of human civilization then the expansion of the
               | universe is not an issue. Traveling between nearby solar
               | systems is very close to impossible, traveling between
               | galaxies is outright impossible.
        
               | OkayPhysicist wrote:
               | The lifetime of human civilization problem is an odd one,
               | because due to relativity, one-way trips are not an
               | unsurpassable hurdle ( 2-3 generations on a 1 G
               | spacecraft to get pretty much anywhere). But you can't
               | come back, because it's basically guaranteed there'll be
               | nothing left for you to come back to. Because while it
               | might take "only" two hundred years from the passengers
               | perspective to reach the edge of the (current) observable
               | universe and come back, they'll be arriving 90 billion
               | years in the future.
        
               | mr_toad wrote:
               | The objects you can (eventually) reach are proportional
               | to your speed. For example at half light speed you could
               | catch up to objects nearly halfway to the Hubble Horizon,
               | about 7 billion light years away.
        
         | clocker wrote:
         | > Lightly is incredibly slow
         | 
         | Its relative! Sitting on a couch and watching the pixel move
         | from the sun to the earth for 8 minutes feels incredibly slow
         | but if you are actually traveling in a light speed aircraft
         | then it won't feel that slow.
        
           | quchen wrote:
           | Quite the opposite, much like when skydiving, going really
           | fast without any close reference point makes everything stand
           | still. And in space, there wouldn't even be (very loud)
           | atmospheric drag to physically remind you about what speed
           | you're actually going.
        
             | jjbinx007 wrote:
             | I believe the OP was referring to relativity - the closer
             | to the speed of light you get the slower time appears to
             | tick. So if you could travel at light speed you'd arrive at
             | your destination immediately from your reference frame, but
             | much slower from another person's.
        
               | dylan604 wrote:
               | Then what's up with all of those sci-fi chows where using
               | FTL still takes some amount of time to arrive?
        
               | krapp wrote:
               | 1) it's better for the plot and drama to have travel
               | time. FTL in fiction is always analagous to some known
               | terrestrial form of travel (usually ships and boats) and
               | the limitations and parameters of FTL in a fictional
               | universe shape the narrative in necessary ways.
               | 
               | 2) it's assumed within the framework of the fictional
               | universe that time dilation isn't taking place because
               | the actual travel is occurring within an external frame
               | of reference like "hyperspace" or a "warp field."
        
               | mr_toad wrote:
               | Screenwriters don't understand much science.
        
           | orobus wrote:
           | If you were _actually_ traveling at the speed of light it
           | wouldn 't feel like anything at all! Photons don't
           | 'experience' time--any length trip would be instantaneous
           | from the traveler's point of view.
        
         | baxtr wrote:
         | Me scrolling is faster than the speed of light!
         | 
         | Nice.
        
           | schaefer wrote:
           | Dude, chill.
           | 
           | We've got to preserve causality. :P
        
         | philwelch wrote:
         | We're barely even using our first solar system, it's way too
         | early to be worried about reaching other stars.
        
           | ClumsyPilot wrote:
           | Exactly, there is free fuel and aluminium just floating by,
           | and we are unable to use them to upgrade our ships or refuel
           | them.
           | 
           | Until we make full use of robotics and 3D printing, there is
           | no point of heading far. And we have all the tools.
           | 
           | Distant stars will not be settled by a fast small ship
           | travelling from earth. They will be settled by a city sized
           | monolith produced by harvesting and smelting an entire small
           | moon
        
             | philwelch wrote:
             | > Distant stars will not be settled by a fast small ship
             | travelling from earth. They will be settled by a city sized
             | monolith produced by harvesting and smelting an entire
             | small moon
             | 
             | I don't even think you'd need a whole moon unless it was a
             | tiny one. Nonetheless, by the time we send a ship to
             | another star, building these kinds of large self-contained
             | habitats will be old hat.
        
         | ClumsyPilot wrote:
         | All of fiction and discourse fails to consider that the Solar
         | System is actually a huge place and just the period of settling
         | and industrialising it will take hundreds of years.
         | 
         | Everyone things that a game breaker technology is better
         | engines, or fusion, or FTL, but they are wrong, the game
         | breaker technology has already happened: 3D printing.
         | 
         | If we can manufacture things with minimal infrastructure using
         | local resources, we can that is all we need.
         | 
         | And all of it reachable with simple nuclear power and
         | technology we have today.
        
         | ck2 wrote:
         | Alternate view:
         | 
         | be thankful things are far apart
         | 
         | a gamma-ray burst from a collapsing star closer than 200 light
         | years away would destroy ALL life on earth
        
         | johnnyjeans wrote:
         | Is light slow? Or is the human perception of time just scaled
         | down as a result of our rapid metabolism and infinitesimality?
         | People historically mistake plants for being inanimate things
         | with no reactivity, that they are far more simple and stupid
         | than they truly are. Outside of a few exotic examples, plants
         | simply operate on a wider timescale that's basically
         | imperceptible without careful and particular observation. It
         | becomes much more apparent how alive plants are when we observe
         | them in a time-lapse. Now realize that plants are still
         | relatively short-lived. The absolute oldest ones only go back
         | to the early neolithic, that's only 14000 years or so. 1000
         | years is a long time for humans, but probably not for the trees
         | where a single one can live 10x that.
         | 
         | From the hypothetical perspective of a star, with a lifespan
         | measured in billions upon billions of years, the entire
         | ecoscape of the world changes in a blink. From the sun's
         | perspective, MENA was green just a very short while ago. Hell,
         | _Pangea_ wasn 't that long ago. At this timescale, continental
         | drift would be as apparent as the movement of boats are to
         | humans. Anything that's working at the cosmic scale where the
         | seemingly low speed of light sounds exhausting is most
         | definitely working at this stellar perspective at the minimum.
         | 14000 years of travel might as well be the equivalent of a 10
         | minute commute to the store.
         | 
         | Philosophically speaking, of course.
        
           | eddd-ddde wrote:
           | I always think of those motor proteins moving along slowly
           | inside our bodies, and wonder if maybe we are just the motor
           | proteins of the cosmic scale.
        
             | M95D wrote:
             | We have a long way to go before we learn to move a star (or
             | a rosette).
             | 
             | https://en.wikipedia.org/wiki/Stellar_engine
             | 
             | https://en.wikipedia.org/wiki/Klemperer_rosette
        
             | IAmBroom wrote:
             | Dude, pass the duchy.
        
           | davidee wrote:
           | Thanks for this.
           | 
           | In addition to the insight, it reminded me to water a plant
           | at a desk I no longer use. The plant's been with me through
           | quite a bit and I have been neglecting it recently as I no
           | longer see it regularly.
        
             | nilamo wrote:
             | Move your plant friend to your new desk?
        
             | randalsedgewick wrote:
             | In turn this reminded me to water my terribly neglected
             | office plant, so thank you!
        
           | mr_toad wrote:
           | > Is light slow?
           | 
           | It's always faster than you or I. Even if we zipped around at
           | relativistic speeds it would still appear the same.
        
           | swyx wrote:
           | humans are a blip. i think the overwhelming scenario is we
           | were a bootloading sequence for silico sapiens.
        
           | chistev wrote:
           | Comments like this are part of the reasons I come here.
        
           | ifa_ wrote:
           | yeah light _is_ actually pretty slow and we hit that in
           | networking and optics pretty often if iirc.
           | 
           | like not even on a human level, universally even on a grand
           | scale the speed of light is almost torturously slow, there's
           | nothing philosophical about it
        
             | procgen wrote:
             | something can only be "slow" relative to something else.
             | it's not an intrinsic property.
        
             | lenkite wrote:
             | Might have been a deliberate rule enforced on the universe
             | to avoid interstellar wars between sapient civilizations.
        
               | lukas099 wrote:
               | But that's making your simulation deliberately less
               | interesting, no?
        
               | chmod775 wrote:
               | Chances are that only a species who, through one way or
               | another, has become very uninterested in warfare could
               | have advanced to the point where they would be able to
               | run such a simulation, otherwise they'd have ended their
               | own existence with their shiny toys before long.
               | 
               | War only occurs if you have _in the literal sense_
               | retarded elements in your advanced species and is
               | nonsensical from an outside POV. A species this advanced
               | would have fixed such shortcomings in itself long ago.
               | 
               | So no, I don't think they'd necessarily be very
               | interested in watching primitive species go to war with
               | primitive weapons.
               | 
               | For all we know the simulation of this universe is
               | happening in their equivalent of an overengineered snow
               | globe, us being an artifact nobody has noticed and that
               | nobody would find particularly interesting if they did
               | notice.
        
           | mjcohen wrote:
           | For very philosophical writings about this, read "Last and
           | First Men" and "Star Maker" by Olaf Stapledon. Written in the
           | 1930's, these describe on a very expansive scale the history
           | of, respectively, humanity and the universe. Very mind
           | bending.
        
           | the_af wrote:
           | > _Is light slow? Or is the human perception of time just
           | scaled down as a result of our rapid metabolism and
           | infinitesimality?_
           | 
           | It's slow for humans to explore the cosmos.
           | 
           | "Slow" is meaningless without a frame of reference, and
           | "humans" seems like a good frame of reference, since it's us
           | -- and not plants or stars -- who are writing on HN to
           | discuss this.
           | 
           | Because it's us, humans discussing this in HN, the frame of
           | reference is implied and it's not necessary to spell it out.
        
           | notjoemama wrote:
           | Light is comparatively and objectively slow in comparison to
           | the distances that exist. Andromeda is 1M light years from
           | us. From that perspective, 300k kph is oddly slow actually. I
           | love the passion that you're brining to the table though. It
           | reminded me of the blue giant stars whose lifespans can be as
           | short as tens of millions of years, more often hundreds
           | though. For billions upon billions, I suppose that would be
           | white and brown dwarfs. Although, if we could orbit black
           | holes and harness the energy of gravity, then we're really
           | talking long time scales. Cracking the aging problem would
           | allow us to think in very long timescales. But I do wonder
           | whether the human psyche could handle such long lifespans.
        
             | bobbylarrybobby wrote:
             | > in comparison to the distances that exist
             | 
             | This leaves out the time component. Who's to say that a
             | year is long? A galaxy a million light years away takes a
             | million years to reach... and maybe that's a short amount
             | of time, to the right observer.
        
               | mgraczyk wrote:
               | Light could only go to Andromeda and back 1000 times
               | before the sun burns out. That's not very many times IMO.
               | On the scale of galaxies, light is slow relative to any
               | timescale relevant to large objects.
        
               | morsch wrote:
               | Carrying the metaphor further, that's closer than America
               | was to Europe in the 18th century.
        
               | darkwater wrote:
               | How many times can you go from Lisbon to Beijing and back
               | by car in your lifetime?
        
               | mgraczyk wrote:
               | Not many, because cars are slow
        
           | tim333 wrote:
           | At the moment humans only live ~90 years which is a blip in
           | cosmic terms, but shortly we should be able to merge with AI
           | and live for billions of years and visit stars.
        
           | api wrote:
           | That's one of the answers to how you could go to the stars:
           | go sloooooow as in slow down your cognition and metabolism so
           | the trip doesn't take long.
           | 
           | Ents could fly to the stars no problem.
           | 
           | Makes me wonder if there might not be a bunch of star faring
           | "slow life" out there that we don't notice for the same
           | reason a hummingbird doesn't notice trees growing.
        
         | mr_toad wrote:
         | > I think we'll have a holodeck before we reach another star.
         | And maybe that'll be enough.
         | 
         | I agree, but not because of the relative difficulty of the
         | technology, but because we spend way more on entertainment than
         | space exploration.
        
         | smeeger wrote:
         | you would need a ship that is also a city. a traveling space
         | station. or probes. if humanity decided to send a small probe
         | to the nearest foreign star, i wonder how many km/h current
         | infrastructure could accomplish
        
         | lisper wrote:
         | It only seems incredibly slow in this model because it doesn't
         | take special relativity into account. If it did, then as you
         | approached the speed of light the Lorentz contraction would
         | make wherever you are heading appear less far away. You can in
         | theory get anywhere in the universe in an arbitrarily short
         | amount of proper time your own reference frame. Of course, you
         | might not survive the G-forces, but that's another matter.
        
           | wafflemaker wrote:
           | Don't forget gravity drive. No more Gs. And the same
           | technology would give us real artificial gravity, not this
           | nauseous rotation artificial gravity.
        
           | dyauspitr wrote:
           | You can accelerate continuously at a comfortable 1g and get
           | to 0.5c in about 5 months. G forces are not the issue.
        
             | lisper wrote:
             | The Lorentz factor at 0.5 c is 0.86 so this only reduces
             | your proper travel time by about 15%. Even at 0.9c the LF
             | is only 0.43, so it would still take you 2 years just to
             | get to Proxima Centauri. And as you approach c, 1G
             | acceleration speeds you less and less. And you also have to
             | slow down at your destination.
        
               | munchler wrote:
               | Not to mention that you also have to survive any
               | collisions with specks of dust in between.
        
         | aledalgrande wrote:
         | Need that warp drive
        
         | swyx wrote:
         | what's your definition of a holodeck? i only know the one from
         | star wars and thats kind of a toy
        
         | UltraSane wrote:
         | Stephen Baxter wrote a story named The Gravity Mine about the
         | descendants of humanity living after all stars have died. They
         | get energy from black holes but even they are starting to
         | noticeably shrink. Their perception of time is billions of
         | times slower than humans and the upshot of this is that the
         | speed of light would actually seem pretty fast.
         | 
         | https://www.infinityplus.co.uk/stories/gravitymine.htm
        
         | somenameforme wrote:
         | Depends on who you mean by we. The universe is weird and it's
         | entirely possible for you or I to travel essentially
         | arbitrarily far in a single human lifetime, easily billions of
         | light years. Relativity doesn't simply work as a speed limit;
         | instead when things approach velocities anywhere near the speed
         | of light, the universe starts contorting itself in really weird
         | ways to maintain the perceived consistency of the speed of
         | light.
         | 
         | From the perspective of somebody in a ship moving at
         | relativistic rates, distances would begin to physically
         | contract, and time itself would begin to speed up relative to
         | an at rest observer. Here [1] is a calculator to see what this
         | all mathematically works out to. For instance, you could travel
         | to Andromeda, some 2 million light years away, in about 28
         | years in a ship that was capable of sustaining acceleration at
         | 1g for 28 years. Of course for everybody back home 2 million
         | years would pass. So if we ever achieve ships capable of this
         | sort of acceleration, life is going to get really weird and
         | non-linear, so far as time is concerned.
         | 
         | And this isn't some just some weird fringe
         | theoretical/mathematical thing. For instance GPS satellites
         | have to compensate for time dilation because relativistic
         | effects, though small in this case, would otherwise have a
         | substantial effect. Another example is at things like the large
         | hadron collider. As a convenient effect of relativistic
         | effects, emergent unstable particles exist far longer than they
         | 'normally' would before decaying due to the fact they're moving
         | at relativistic rates.
         | 
         | In other words, this is all very real. The only questionable
         | issue is whether we can discover some sort of an energy source
         | capable of accelerating a ship at 1g for tens of years, and
         | develop sufficient shielding for such a vessel. That's still
         | very much in the domain of sci-fi, but simultaneously seems
         | like something that one wouldn't be entirely surprised to see
         | was discovered just a century from now. This was the most
         | tantalizing possibility behind the EMDrive stuff. [2] Well that
         | or infinite energy, but it seems that universe won't be broken
         | quite so easily just yet.
         | 
         | [1] -
         | http://www.convertalot.com/relativistic_star_ship_calculator...
         | 
         | [2] - https://en.wikipedia.org/wiki/EmDrive
        
       | CapsAdmin wrote:
       | I've seen countless analogies that explain the size of space, but
       | this was really something else. Especially how frustratingly slow
       | the speed of light felt.
        
       | robin_reala wrote:
       | The light speed toggle really hammers home the emptiness. Like, I
       | _know_ that the Earth is ~8 light minutes out, but sitting and
       | waiting 8 minutes for a few pixels to appear when scrolling away
       | from the sun...
        
         | jstummbillig wrote:
         | and even this is not making it super tangible, because the
         | speed of light to monkey brains is basically infinite.
        
       | kennu wrote:
       | Scrolling with mouse scroll wheel a few hundred thousand
       | kilometers at a time is so much work that I gave up :-(
        
         | tacker2000 wrote:
         | Its quite cool on the phone
        
         | blueflow wrote:
         | Repetitive strain injury any% speedrun
        
         | werdnapk wrote:
         | Click on the planet symbols at the top to fast track.
        
         | mdaniel wrote:
         | I'm thankful that the view-source:https://joshworth.com/dev/pix
         | elspace/pixelspace_solarsystem.... allows one to see the
         | annotations since clicking on the planet jumps scrolls past
         | them. My gratitude for not baking such things into 8MB of JS
         | 
         | Also thanks to the view-source I learned that it offers
         | different units, including busses, Great Wall of China, etc
        
       | mxuribe wrote:
       | This is truly marvelous! Not only is the horizontal scroll really
       | extra awesome for making me feel the distances...but as others
       | stated, the moment you toggle on the light speed....wow, it
       | really is quite profound! Amazingly done!
        
       | robertlagrant wrote:
       | Wot no Oort Cloud?
        
       | cmsefton wrote:
       | Previous discussions (there are many!)
       | 
       | https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
        
       | bradley13 wrote:
       | I've seen models like this before. We live in a universe with
       | many, _many_ orders of magnitude. In both directions. Living
       | creatures to small to see, space too big to comprehend.
       | 
       | Mining asteroids for space resources sounds great, right up until
       | you consider the distances involved. Living on Mars - yes, we
       | really should - but you sure aren't going to support a colony
       | long-term from anywhere but local resources.
        
         | zirgs wrote:
         | We are pumping oil that's located under the seabed. It would
         | have seemed completely insane in the 19th century when all oil
         | was easily accessible. Asteroid mining might be feasible in a
         | few decades. If it really gets going - it could make gold as
         | cheap as aluminium is today.
        
       | stevage wrote:
       | I just love that this is still online after all these years.
        
       | susam wrote:
       | When I was dabbling with POV-Ray many moons ago, I drew the
       | planets of our solar system to scale with it. You can see it
       | here: https://github.com/susam/pov25#planets
       | 
       | A friend once asked if I couldn't show the planets in orbit
       | rather than lying flat on a plane. I could, of course, but this
       | is ray tracing. What do planets actually look like to human eyes
       | from Earth? Just tiny dots.
       | 
       | If I were to show them in their proper orbits at scale using
       | perspective projection, I'd only be able to render one planet
       | large enough to be visually interesting. The rest would appear as
       | small dots. I didn't want to use an orthographic projection, as
       | it wouldn't reflect how we actually see the universe.
       | 
       | Those were, of course, limitations of a still image. An
       | interactive page like the one in the original post does a
       | fantastic job of conveying the vast scale of our solar system,
       | both in terms of the sizes of the planets and the immense
       | distances between them.
        
         | dahart wrote:
         | Would you have to use double precision to ray trace the planets
         | in their proper orbits at scale using either perspective or
         | orthographic projection? With the ratio of Neptune's distance
         | from the sun to its radius being almost 2M, I'm guessing fp32
         | rounding would turn Neptune into a couple of squares if the sun
         | was at the origin. What other challenges would there be? Maybe
         | I'll try it today just for fun.
        
           | dahart wrote:
           | I tried it, including Pluto, and it works fine. Shading is
           | quantized at Pluto but the spheres are all round.
        
       | mg wrote:
       | The way I often visualize the solar system is:
       | 
       | If the sun would be the size of a coin, then earth would be
       | around 2m away from it and so small you could barely see it.
        
       | okokwhatever wrote:
       | Lovely
        
       | technothrasher wrote:
       | I remember back in elementary school, way before we had such
       | things on computer, we had a vinyl roll for the age of the
       | planet. You'd roll it out in the hallway, starting with present
       | day and watch as the different time periods came into view. You
       | were just a few feet at the origin of man, at the end of the
       | hallway by the time you got to the beginning of Cambrian era, and
       | out the door and across the huge athletic field before you got to
       | the formation of the planet.
        
       | 1over137 wrote:
       | How does this website work? I feel like I'm stuck on the first
       | screen maybe? It says 'scroll to explore' but there are no
       | scrollbars. Does it only work with a mouse with a scroll wheel?
        
         | jenoer wrote:
         | Scroll horizontally, to the right.
        
       | NKosmatos wrote:
       | We're never going to leave this planet/solar system if we don't
       | discover FTL (Faster Than Light) travel. Pretty scary if you
       | think about how ridiculously empty is space.
        
         | Andrex wrote:
         | We can _leave_ it pretty easily. :p Only took Voyager 1 about
         | 40 years.
         | 
         | If ~1.0C is the fastest man can travel, that's still pretty
         | good. Alpha Centauri is in reach (less than five light-years).
        
           | jandrese wrote:
           | Alpha Centauri is a triple star system with no habitable
           | planets. Why in the hell would you go there? Sending people
           | to another solar system is so resource intensive that
           | assuming you can convert the entirety of Jupiter into some
           | kind of orders of magnitude more efficient exotic rocket fuel
           | you might have enough resources for a small handful of
           | expeditions, so you really need to make them count.
           | 
           | Maybe it would make sense if you could convert the mass of
           | Proxima Centauri into rocket fuel to fund more expeditions?
           | That seems like a fairly long term plan though.
        
       | raindev wrote:
       | The planets are just grains of sand in a vast empty space.
        
       | gary17the wrote:
       | How does all that space out there make you feel about the 30
       | years of paying off your mortgage for all that 0.25 acres of land
       | you own? ;) J/K
        
       | tomxor wrote:
       | Shameless plug: Accurate solar system in 192 Bytes:
       | 
       | https://www.dwitter.net/d/26521
       | 
       | The red bit is the sun. 1000 kilometers per pixel, and 1000
       | seconds per second.
       | 
       | They all fit onto the screen by looking through the orbital
       | plane, as if through a telescope from a distant world, i.e
       | effectively an orthographic projection. The orbits are accurate
       | in terms of mean orbital distance (in reality there is slight
       | perturbance) and sidereal periods.
        
         | darajava wrote:
         | Incredible - how does this work?
        
           | tomxor wrote:
           | You mean technically? I should have posted the beta dwitter
           | link which has the "compress" toggle, because most dweets are
           | unicode packed. https://beta.dwitter.net/d/26521
           | 
           | Here's the js anyway:                 for(i=10;i--;x.fillStyl
           | e=R(i-8||255),x.beginPath(x.fill()))x.arc(960+[45,29,14,8,2,1
           | .5,1,.6,0,0][i]*1e5*S(t/5e3/[165,84,29,12,2,1,.6,.2,1,1][i]),
           | 540,[24,25,58,69,3.4,6.4,6,2.4,696,2e3][i],0,7)
           | 
           | This one is actually relatively simple to explain, it loops
           | over the 10 planets (i), and draws a circle for each, with
           | the position and size all being defined in the x.arc method.
           | Planets are differentiated by the arrays of values selected
           | by [i]. The X position is calculated as the orbital distance
           | multiplied by the sine of time / orbital period... d x
           | sin(t/p). But d and p are substituted for the value for each
           | planet using the arrays [1,2,3][i].
           | 
           | Surprisingly the precision used in those encoded values is
           | enough at 1000km per pixel (I checked).
        
             | ByThyGrace wrote:
             | I presume including Pluto's parameters in the array is both
             | a rebellious statement and a brag. ("Yes, my JS snippet
             | could have been even shorter if you asked the IAU.")
        
               | tomxor wrote:
               | Actually I couldn't fit Pluto, I sacrificed everything I
               | could, but to fit it would require sacrificing the
               | precision of Mars, Earth and Mercury (dropping the
               | decimal), but I wanted to maintain enough precision to be
               | able to tell them apart by size (which you just about can
               | at full screen due to antialiasing)... Otherwise I
               | definitely would have included it for that very sentiment
               | ;)
               | 
               | The reason there are 10 radi is for 8 planets + sun +
               | drawing the black backdrop (2e3):
               | [24,25,58,69,3.4,6.4,6,2.4,696,2e3]
        
       | jethkl wrote:
       | There are many physical scale models of the solar system around
       | the world, many walkable, some bikeable:
       | https://en.wikipedia.org/wiki/Solar_System_model
       | 
       | I've seen several, Planet Trek in Wisconsin is a good bikeable
       | one with high quality signage. The sun is downtown, the moon is
       | the size of a peach pit, Pluto is ~20 miles away.
        
         | idlewords wrote:
         | And for the lazy, there's the 1:1 scale model under your feet.
        
       | amiga386 wrote:
       | I love how simple the HTML/CSS is. Absolute positioning with
       | _really_ large left: values.                   #saturn {
       | position: absolute;             left: 412397px;
       | height: 34px;             width: 65px;             fill: #ffa043;
       | }
        
         | neuroelectron wrote:
         | Caused Brave in iOS to crash. I have a newer iPad mini with
         | 12GB ram too. But luckily It didn't crash until I tried to
         | close the tab.
        
           | pc86 wrote:
           | This seems like a browser issue more than anything else. Yes
           | it's "weird" to have millions of pixels horizontally on a
           | page that is only a few thousand pixels tall, but it seems
           | like an absolutely reasonable edge case that the browser
           | should support.
        
             | Sharlin wrote:
             | "Why not save space by storing dimensions as uint16
             | internally?"
        
               | Dylan16807 wrote:
               | For the record, this HN page is already about halfway to
               | overflowing uint16. The most popular HN page in the last
               | day _would_ overflow uint16.
        
             | zhengyi13 wrote:
             | I feel there's a joke here about "edge" cases from
             | scrolling ridiculously long horizontal distances, but I'm
             | not smart enough to make it.
        
               | wltr wrote:
               | And then it's asking for Internet Explorer joke then, as
               | an explorer something, not I'm not able to come up with
               | it either.
        
         | 2OEH8eoCRo0 wrote:
         | We have come full circle. I'd imagine that px uses a surprising
         | amount of abstraction.
        
           | cheschire wrote:
           | Anyone that has tried to absolutely position shapes on an
           | Excel spreadsheet via code would probably agree.
           | 
           | Who the hell decided to make EMU's??
        
         | Zardoz84 wrote:
         | Huge values could rise problems on IE (if someone keep using it
         | and supporting it)
        
       | whoisthemachine wrote:
       | I love it, I always love these things. Still, given this is a
       | technical site, one small nitpick is that it would be nice on
       | hover to see how many pixels the current object is.
        
         | mdaniel wrote:
         | No need to hover, the drop-down next to the measurement at the
         | bottom has Pixels. Clicking on the Pluto quick-nav shows that
         | it is 1,700,530px
        
       | zengineer wrote:
       | Love it! Are there stats on how many people scrolled to the end?
       | :)
        
       | eric-p7 wrote:
       | You may think this page is big. But that's just peanuts to space.
        
       | Symmetry wrote:
       | One thing to notice is how small Mercury is, only 1 pixel like
       | the moons that show up. Here's a good photo size comparison.
       | Mercury is smaller that two of the solar system's moon!
       | 
       | https://en.wikipedia.org/wiki/Planetary-mass_object#/media/F...
       | 
       | EDIT: And Pluto is smaller than all the moons almost anyone has
       | heard of.
        
       | j_m_b wrote:
       | One of my favorite visualizations of the scale of the solar
       | system is from Stephen Hawking's Genius.
       | 
       | https://mass.pbslearningmedia.org/resource/hawking_genius_ep...
       | 
       | It's a hands-on, practical example of how far things are away
       | that we can easily visualize. I highly recommend the rest of the
       | series as well. It's one of the best science shows ever produced.
       | It shows the practical path of scientific discovery. You can
       | watch is on the PBS app, which requires a $60 a year pass. Highly
       | worth it. (I have no affiliation with PBS)
        
         | Kuyawa wrote:
         | I've always used this aprox dimensions:                 Sun
         | diam   1,400,000 km       Eth diam      13,000 km       Sun
         | dist 150,000,000 km       Mon diam       3,500 km       Mon
         | dist     300,000 km
         | 
         | Lets divide it all by 1M. So if the sun is 1.4m in diameter, it
         | would be located 150m from earth which would be 13mm in
         | diameter and the moon would be 3.5mm located 0.3m from earth
         | 
         | Simply put, imagine a yellow beach ball the size of a washing
         | machine located a block and a half away from your house, a blue
         | marble being the earth on one side of your keyboard and a
         | peanut being the moon on the other side
        
           | Kuyawa wrote:
           | Now, using the basketball 24cm (earth) and tennis ball 6.5cm
           | (moon) comparison, they would be separated by 7m in your
           | living room and the sun would be 13m tall (a cherry tree)
           | located at 3km from your house
        
         | socalgal2 wrote:
         | Not the same but related? Powers of 10 by Eames
         | 
         | https://www.youtube.com/watch?v=0fKBhvDjuy0
         | 
         | Interestingly, that Hawking visualization makes all the same
         | affordances mentioned in the 1 pixel visualization. They show
         | the earth and moon to scale, then the video shows an aerial
         | view with all the planets much too large. Jupiter is 2x the
         | size of the sun. Saturn and its rings 2x that.
        
       | jadbox wrote:
       | Unrelated, but the Elon dream of getting a human colony on Mars
       | seems beyond imagination. Ignoring safety of such a long travel,
       | the radiation issue of Mar's surface, and the massive
       | infrastructure to have a self-sustainable biosphere (also somehow
       | protected from radiation) to recycle enough oxygen, we still have
       | to deal with the immense number of failures that could happen
       | with no way to send help.
       | 
       | Like, building a fully self-sustainable underwater city or moon
       | base would be far more in reach. It feels that SpaceX should
       | start with prototyping these safer alternatively before
       | overreaching to something 100x more challenging and dangerous.
        
         | brazzy wrote:
         | It's very clearly not "beyond imagination". It doesn't require
         | any fundamentally new technology.
         | 
         | It may well be beyond our ability to practically apply those
         | technologies at the required scales and reliability levels, but
         | that's hardly unimaginable.
        
           | IAmBroom wrote:
           | Preventing cancerous damage from radiation is absolutely
           | beyond our tech.
           | 
           | Unless you consider launching a lead-lined spaceship "within
           | our tech."
           | 
           | The marsonauts won't die before reaching Mars, but their
           | lifespans will be significantly shortened.
        
         | jandrese wrote:
         | > Like, building a fully self-sustainable underwater city or
         | moon base would be far more in reach. It feels that SpaceX
         | should start with prototyping these safer alternatively before
         | overreaching to something 100x more challenging and dangerous.
         | 
         | I've been beating this drum for years. Elon is 100% focused on
         | building the rocket that can get to Mars and neglecting
         | absolutely everything else about the project. Where is the self
         | contained biosphere pilot program on Earth that tests the Mars
         | habitat? To be anywhere close to Elon's timetable it needs to
         | be running today, and honestly it should have been running
         | years ago. Given the extreme reliability requirements it needs
         | long term testing to build any confidence at all in the
         | numerous technologies involved. The closest model we have is
         | the ISS, and it's mostly shown that we aren't ready for a Mars
         | habitat. The ISS requires way too much maintenance and ground
         | support.
        
           | jandrese wrote:
           | The problem with Mars is that if something goes wrong you
           | can't just "fly back on the rocket". The launch windows are 2
           | years apart. You either fix it in place or you die.
        
         | _fizz_buzz_ wrote:
         | At least theoretically it should be doable. But I think it will
         | be similar to the moon landings. My prediction: People are
         | going to lose interest in the project very quickly. It will be
         | prohibitively expensive to maintain and there is simply nothing
         | to do. You couldn't even really have a remote programming job
         | there. A light round trip takes between 6 and 44 minutes,
         | completely unsustainable.
        
         | Digit-Al wrote:
         | If you're really interested in a deep dive on this subject then
         | I really recommend "A City On Mars" by Zach and Kelly
         | Weinersmith (of SMBC). It goes very deep into things like - can
         | you have babies successfully in space?
        
       | drewchew wrote:
       | I've probably thought about this website daily or weekly since it
       | originally came out. Glad to know it still exists.
        
       | botverse wrote:
       | I've been thinking about how to teach the size and proportions of
       | the solar system to my kids, I've bought a couple of packs of
       | blank RFID cards on which I intend to paint the planets over a
       | starred background. And then walk with my kids the meters
       | necessary to cover the distances before displaying them. What I
       | don't know is if there is a clever way to use the RFID tech, this
       | website kinda offers an idea.
        
         | ge96 wrote:
         | space engine is neat
        
         | dcminter wrote:
         | Or you could come to Sweden :)
         | 
         | https://en.m.wikipedia.org/wiki/Sweden_Solar_System
        
       | ge96 wrote:
       | I like the other one where you can zoom in/out to planck level or
       | to the unobserved universe
        
       | silasdb wrote:
       | This is a great website--it reminds me of _To Scale: The Solar
       | System_ [1], a mini-documentary where people attempt to build a
       | true-to-scale model of the Solar System. It makes me feel like a
       | tiny speck of dust, floating in the vastness of nowhere...
       | 
       | [1] https://www.youtube.com/watch?v=zR3Igc3Rhfg
        
       | sizzzzlerz wrote:
       | Douglas Adams said it best:
       | 
       | Space is big. You just won't believe how vastly, hugely, mind-
       | bogglingly big it is. I mean, you may think it's a long way down
       | the road to the chemist's, but that's just peanuts to space.
        
       | smeeger wrote:
       | why have we not shot a probe toward the nearest foreign star?
        
         | foxglacier wrote:
         | I'm not sure we'd be capable of receiving any signal it sent
         | back to us, would we?
        
         | tombrandis wrote:
         | There was a plan in ~2016 backed by Zuckerberg, Hawking and
         | some entrepreneur but it didn't really get anywhere (in a
         | literal sense). Research for it stopped in 2022 because of a
         | "lack of funding".
         | 
         | https://en.wikipedia.org/wiki/Breakthrough_Starshot
         | 
         | https://interestingengineering.com/innovation/mark-zuckerber...
        
       | kazinator wrote:
       | > _We 're always trying to come up with metaphors for big
       | numbers. Even so, they never seem to work._
       | 
       | Yeah, that Googol often doesn't work.
        
       | Zardoz84 wrote:
       | Pedantic me : Pluto isn't a planet.
        
       | stackedinserter wrote:
       | It's not space that's big and out of reach, it's just us living
       | too fast.
        
       | kristopolous wrote:
       | This makes the Theia hypothesis all the more extraordinary
       | https://en.wikipedia.org/wiki/Theia_(hypothetical_planet)
       | 
       | I believe the scientific record is drawing a consensus on this as
       | the moon's origin but the wild sparseness of space just makes
       | this sound really unusual.
        
       | aledalgrande wrote:
       | This is super cool. It's crazy to think about asteroids in any
       | depiction of the solar system look so packed that I thought a
       | spaceship would never be able to pass through unscathed, but here
       | it's all black because they are basically irrelevant lol
       | 
       | Also crazy how far Jupiter's gravity can keep a moon??
        
       | nothacking_ wrote:
       | Importantly, the planets aren't actually lined up nicely like on
       | the site. Right now, Mars is ~5 times further then shown.
       | 
       | That's why so many people were taking pictures of Mars back in
       | January, when it was actually possible to take see detail. Right
       | now it just looks like a red orb.
        
       | dang wrote:
       | Related. Others?
       | 
       |  _If the moon were only 1 pixel_ -
       | https://news.ycombinator.com/item?id=39686916 - March 2024 (1
       | comment)
       | 
       |  _If the Moon Were Only 1 Pixel (2014)_ -
       | https://news.ycombinator.com/item?id=32936581 - Sept 2022 (108
       | comments)
       | 
       |  _If the Moon Were Only 1 Pixel (2014)_ -
       | https://news.ycombinator.com/item?id=27573172 - June 2021 (69
       | comments)
       | 
       |  _If the Moon Were Only 1 Pixel (2014)_ -
       | https://news.ycombinator.com/item?id=21735528 - Dec 2019 (82
       | comments)
       | 
       |  _If the Moon Were Only 1 Pixel - A tediously accurate map of the
       | solar system_ - https://news.ycombinator.com/item?id=13790954 -
       | March 2017 (81 comments)
       | 
       |  _If the Moon Were Only 1 Pixel - A tediously accurate map of the
       | solar system_ - https://news.ycombinator.com/item?id=13217129 -
       | Dec 2016 (11 comments)
       | 
       |  _If the Moon Was Only 1 Pixel_ -
       | https://news.ycombinator.com/item?id=12038584 - July 2016 (4
       | comments)
       | 
       |  _A Ridiculously large accurate scale model of the Solar System_
       | - https://news.ycombinator.com/item?id=10330303 - Oct 2015 (1
       | comment)
       | 
       |  _If the moon were only 1 pixel: a scale model of the solar
       | system_ - https://news.ycombinator.com/item?id=7551423 - April
       | 2014 (17 comments)
       | 
       |  _If The Moon Was Only 1 Pixel_ -
       | https://news.ycombinator.com/item?id=7341690 - March 2014 (178
       | comments)
        
       | initramfs wrote:
       | nice!
        
       | chachacharge wrote:
       | sit back and relax for my 1px review
       | 
       | tedious=true, basicallyLame=true, is1px=false
        
       | idlewords wrote:
       | The universe is a UI nightmare
        
       | sepidy wrote:
       | This was so cool I would add the planets as indicators on the
       | right side and by clicking on them I would move the timeline fast
       | to reach them
        
         | fkyoureadthedoc wrote:
         | somewhat defeats the point I think (but they are at the top if
         | you really want to)
        
       | knoxg wrote:
       | Look I'm no astronomer, but I'm pretty sure celestial bodies all
       | have elliptical orbits, so if you're going to label something as
       | 'tediously accurate' you should give some indication that the
       | distances from the sun are changing over the orbital period.
        
         | rstuart4133 wrote:
         | Didn't have the patience to read the fine article?
         | Understandable I guess, but I thought it was worth the effort.
         | Quoting from it:
         | 
         | > All these distances are just averages, mind you. The distance
         | between planets really depends on where the two planets are in
         | their orbits around the sun.
        
       | joshbetz wrote:
       | Reminds me of a 23 mile long model of the solar system in Madison
       | https://www.astro.wisc.edu/outreach/planet-trek/
        
       | computator wrote:
       | Given the great distances and how small the planets seem at that
       | scale, I'm surprised that we can see any of the planets with the
       | naked eye. Thinking about Jupiter, it's 140K km in diameter and
       | about 629M km from Earth. That's a ratio of 1:4500. So imagine a
       | U.S. dime that is 1.8cm in diameter placed 1.8 x 4500 = 8100 cm
       | away. Would you be able to see a dime that it 81m or 266ft away
       | at nighttime, assuming it slightly illuminated? We can see
       | Jupiter, so I guess we should be able to see the illuminated dime
       | too.
        
       | bandrami wrote:
       | I've always thought that people pushing for colonization or even
       | commercial exploitation of space simply don't have a good sense
       | of how _far_ things are and how _empty_ the space between us and
       | those things are.
        
         | manquer wrote:
         | That has always been the case, there is loads of empty distance
         | between big population centers even today there are big cities
         | many hours by flight from anywhere else of interest.
         | 
         | In the age of sail, people were perfectly willing to spend
         | months in transit .
         | 
         | Transit times for most objects of commercial interest (i.e.
         | upto moons of Saturns) is only in years if you use a low
         | energy/Delta-v Hohmann transfer orbits and/or gravity assists
         | as is common today for probes.
         | 
         | Direct transfer would be expected for human transits , those
         | can be fairly quick . Transfers to mars within the next 1-2
         | decades is doable in 6months or less.
         | 
         | There are no fundamental breakthroughs needed to go any orbits
         | we would be interested in 1 year or less by end of this
         | century.
         | 
         | On the other hand I do agree going interstellar is a whole
         | different scale of empty and without near light speed (even
         | with ) is probably out of reach .
        
       | gblargg wrote:
       | > tediously accurate
       | 
       | Could the planets and moons ever all be aligned like this when
       | viewed from an infinite distance?
        
       | KolibriFly wrote:
       | I love the little facts sprinkled throughout
        
       | kitchendesign wrote:
       | How many times can you go from Beijing to Lisbon ?
        
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