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Can life exist on a planet without a star?
- RIMR 12y agoI also wonder about rogue planets near the galactic center. They wouldn't need to have their own star to get bathed in plenty of light from other nearby stars. There would be no such thing as night and day either.
- bjwbell 12y agoThere is too much radiation... for life as we know it on those planets.
- kijin 12y agoWater is pretty good at blocking radiation [1]. Life could exist in a layer of the ocean where ionizing radiation is reduced to a survivable level but plenty of visible light gets through. Or the planet could be teeming with water bears. [1] https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/
- nsajko 12y agoI think the galactic bulge probably doesn't support life because of ionizing radiation and unstable orbits.
- Retra 12y agoYou might be underestimating the distance between stars in the galactic center...
- Crito 12y agoIt isn't a great source, but this seems to suggest it would actually be pretty significant: > "Near the galactic center, the average distance between neighboring stars would be only 1000 AU (about a light-week). If the Sun were located within a parsec of the galactic center, there would be a million stars in our sky with apparent brightness greater than Sirius. The total starlight in the night sky would be about 200 times greater than the light of the full moon; you could easily read the newspaper at midnight, relying on starlight alone." http://www.astronomy.ohio-state.edu/~ryden/ast162_7/notes31.html http://www.astronomy.ohio-state.edu/~ryden/ast162_7/notes31....
- gambiting 12y agoObviously this is not a perfect comparison, but even on Earth, if the night is cloudless, you are away from any cities, and the moon is not visible, the stars provide some light. Not bright enough to see clearly, but you can see a little bit, even with our weak human eyes. So I imagine that even on a planet without a star it wouldn't be 100% dark, there would be some light.
- spartanatreyu 12y agoJust think about the early universe, a rouge planet would only need a sufficiently thick atmosphere. The universe itself would have been so hot that liquid water would have existed without a star's heat.
- cozzyd 12y agoI don't think the early universe had sufficient amounts of heavy elements to form planets... everything heavier than lithium is made by stars.
- x3n0ph3n3 12y agoNot entirely true. Everything heavier than Boron is made by stellar nucleosynthesis: http://en.wikipedia.org/wiki/Cosmic_ray_spallation#/media/File:Nucleosynthesis_periodic_table.svg http://en.wikipedia.org/wiki/Cosmic_ray_spallation#/media/Fi...
- JacobAldridge 12y agoWhat sort of speed might some of these rogue planets be moving at? While the faster they move, the harder it would be to 'latch on' to a stable orbit / land, could they more than a waypoint to distant stars - might they be a 'spaceship'? Although this would require us to 1) discover a dark planet, 2) moving at an appreciable percent of lightspeed, 3) with enough time to reach it, and 4) heading in the right direction so we could alight at a nearby solar system. If colonization sounds hard, how about those hitchhiking odds - infinitely improbable!
- jessriedel 12y agoNo, there shouldn't be any rouge planets moving fast enough. Stars at our distance from the galactic center move at roughly 230 km/s, with relative speeds of 10-30 km/s. The escape velocity from the galaxy is ~550 km/s, which is something like 0.2% light speed. Very few objects get accelerated above this speed, and when they do they leave the galaxy (so the probability that we pass one going by is negligible).
- sdrothrock 12y ago> No, there shouldn't be any rouge planets moving fast enough. For comparison's sake, the only rouge planet that we know of is Mars, which moves around 24 km/s. :)
- sova 12y ago24 km/s relative to whom/what? =)
- mirimir 12y agoThe discovery of hypervelocity stars (HVS) leaving our galaxy with speeds of nearly $10^{3}$ km s$^{-1}$ has provided strong evidence towards the existence of a massive compact object at the galaxy's center. HVS ejected via the disruption of stellar binaries can occasionally yield a star with $v_{\infty} \lesssim 10^4$ km s$^{-1}$, here we show that this mechanism can be extended to massive black hole (MBH) mergers, where the secondary star is replaced by a MBH with mass $M_2 \gtrsim 10^5 M_{\odot}$. We find that stars that are originally bound to the secondary MBH are frequently ejected with $v_{\infty} > 10^4$ km s$^{-1}$, and occasionally with velocities $\sim 10^5$ km s$^{-1}$ (one third the speed of light), for this reason we refer to stars ejected from these systems as "semi-relativistic" hypervelocity stars (SHS). http://arxiv.org/abs/1411.5022 http://arxiv.org/abs/1411.5022 There could also be hypervelocity planets, right? Catching up to them would be hard, though.
- jaytaylor 12y ago"Most of Earth’s internal heat was delivered by the giant collisions that built the planet, a large portion of which remains locked inside its crust. This heat slowly trickles to the surface, providing a source of internal energy that has endured since the Earth formed. This interior heat will last for billions of years to come, but it’s a puny amount of energy, 3,000 times smaller than the sunlight that blasts the Earth daily." Do this mean 3,000 times less than the Suns total daily output, or 3,000 times less than the sunlight that physically hits the earth daily? I suspect the latter, but I still find this surprising. If daily sunshine hitting the earth is so massive then let's make solar work! If we could just collect even a fraction..
- themeek 12y ago> 3,000 times less than the sunlight that physically hits the earth daily This one.
- yongjik 12y agoI don't think this sentence is true: > Most of Earth’s internal heat was delivered by the giant collisions that built the planet, a large portion of which remains locked inside its crust. In 19th century, Lord Kelvin estimated the age of Earth using this method, arriving at somewhere between 20 and 400 million years[1], much shorter than 4.6 billion years currently accepted. It turns out radioactive decay keeps the Earth's inside warm for a much longer time. (I.e., assuming Kelvin's calculation was correct, without radioactivity the Earth's core would have frozen over within the first 400M years.) [1] http://en.wikipedia.org/wiki/Age_of_the_Earth#Early_calculations http://en.wikipedia.org/wiki/Age_of_the_Earth#Early_calculat...
- hyperpallium 12y agoTidal friction from the moon (and to a lesser extent from the sun) would also have contributed.
- msane 12y agoYou are right - we now know that half of the heat in the core is from fission!
- bjwbell 12y agoStarted off good and then lost me when he talked about using them for stepping stones to the stars. I'm confused about that. A rogue planet in itself makes a terrible colony. And by stopping at one you about double(!) the energy/time needed to leave the solar system.
- jerf 12y agoAt the moment, the most feasible way I see to the stars is via laser-launched ship. The cruel mistress that is the rocket equations don't favor even a self-contained starship driven by 100% efficient antimatter reactions, to say nothing of things that might actually work. Leaving your engine behind is almost a necessity. But even if you try to launch things from a solar-system based laser station the physics still don't really work out well. Light-years is a long way to maintain a focus for the beam. Some have decided this means star travel is impossible; I say it just limits how quickly we can do it. We could launch very large ice asteroids with nanotech unmanned fusion stations that construct lasers ("vigorous handwave about magic here") and create ourselves a series of stepping stones to a star. It would take a long time, not least of which is because we would also need to set up the "stepping stones" to stop us on the other end, too! But in theory it seems like it would "just" be a matter of time. Lots of time. But a whole star system on the other end! It's a pretty big payoff for a strapping young Kardashev II civilization. (Note that "just send information" only works after you deliver a physical package to the other end which would be capable of receiving it and doing something with it, and even nanotech is unlikely to be able to land anywhere to begin its lengthy self-replicating process to bootup civilization on the other end if it's merrily passing through a system at 80% the speed of light relative to the local rest frame.) If you were lucky enough to stumble on to one of these planets in the way, it would provide a pretty nice shortcut to setting up your bridge by providing you a nice, huge power source (if you can find a lot of hydrogen lying around somewhere, which is a reasonable guess) that's already more-or-less at rest in the galactic frame, allowing you to use it to relatively easily create more stages on the enormous pipeline, and allowing you the ability to relatively easily replenish the stages in the middle. (If that's even desirable... perhaps the stages can be retargeted to other stars or something once the bootstrap package is successfully delivered.) ... of course, the article's starting with "10,000 years in the future" is probably not a terrible guess about all this, as such things go. This is a guaranteed-slow process, trading time for space. Tell your great-grandchildren to ask their great-grandchildren how the initial plans to make the initial plans for all this are going, and say "hi" to the future for you. Saying "we" will do this might very well be considered to be rather impudent of me, much like Napoleon trying to claim some sort of perceptible credit for the Hoover Dam.
- 3pt14159 12y agoCould you imagine being that lifeform that cored through the kilometres of ice to finally find an empty space with starlight shining down on you? Alone in a void, the closest celestial being is 10 light years away. Fission could power you for a long time, but rather than looking at the planet as a place fixed, the species could begin to think about where to go. As a planet. They may question whether life on a planet orbiting a sun is even possible (wouldn't it be too hot to form an ice layer?!) but where else could they head? Fascinating.
- adrianhoward 12y agoNot quite that scenario (ice encased planet orbiting a sun) but close in this rather nice SF short "That Other Sea" http://escapepod.org/2014/01/31/ep433-sea/ http://escapepod.org/2014/01/31/ep433-sea/
- gokhan 12y agoNightfall might have a somewhat similar plot, discovery of the universe by otherwise unsuspecting population of a planet. http://en.wikipedia.org/wiki/Nightfall_%28Asimov_short_story_and_novel%29 http://en.wikipedia.org/wiki/Nightfall_%28Asimov_short_story...
- madaxe_again 12y agoIn the same vein as the other sci-fi responses... Fritz Leiber's "A Pail of Air" stuck in my mind, hard, as a kid. Earth flung off into interstellar space, ensuing hijinks. http://www.baenebooks.com/chapters/0743498747/0743498747___6.htm http://www.baenebooks.com/chapters/0743498747/0743498747___6...
- stevenh 12y agoI bet the sky would look very different to them, too. If they did evolve eyes at all, it would probably only be in order to detect thermal radiation from other life forms on the planet; so infrared, microwave, and/or radio frequencies, but not visible light. They may even be able to plainly see the cosmic microwave background with the naked eye. It might even be blindingly bright to them.
- anonymfus 12y ago
- irixusr 12y agoThe ontological argument mated with the spaghetti monster and we got this argument. I can envision how this planet could exist, and I can't prove it doesn't exist. Therefore it does. To make it sound scientific I'll replace "it does" with "it might"
- mcdougle 12y agoIt doesn't come across like it's trying to really prove anything exists or is true. Just some fun speculation and what it might mean if it were true.
- betawolf33 12y agoThis reminds me of a short story about Earth being flung from the solar system by a rogue star. People survive, and one family in particular survives by boiling frozen oxygen 'snow' over a fire. https://en.wikipedia.org/wiki/A_Pail_of_Air https://en.wikipedia.org/wiki/A_Pail_of_Air http://www.baenebooks.com/chapters/0743498747/0743498747___6.htm http://www.baenebooks.com/chapters/0743498747/0743498747___6...
- serf 12y ago> https://en.wikipedia.org/wiki/A_Pail_of_Air https://en.wikipedia.org/wiki/A_Pail_of_Air Los Alamos, Argonne, and Tana Tuva. Was Tana Tuva a topic of discussion during this time period? I remember Richard Feynman wrote quite a bit about it, too.
- andyjohnson0 12y agoFeynman's friend Ralph Leighton wrote about Felnman's long-standing desire to go there [1]. The BBC Horizon programme had an episode called "The Quest for Tannu Tuva" [2] which might be on youtube. [1] http://www.amazon.co.uk/Tuva-Bust-Richard-Feynmans-Journey/dp/0393320693 http://www.amazon.co.uk/Tuva-Bust-Richard-Feynmans-Journey/d... [2] http://sciencek.com/video/1151/horizon-1988x25-the-quest-for-tannu-tuva-1988-07-04/ http://sciencek.com/video/1151/horizon-1988x25-the-quest-for...
- daltonlp 12y agoDark Eden is a recent novel with exactly this premise. It's an excellent book: https://www.goodreads.com/book/show/18166988-dark-eden https://www.goodreads.com/book/show/18166988-dark-eden
- rspeer 12y agoFor what it's worth, I enjoyed the world-building but found the actual plot too simplistic. Kind of like Flatland in that regard, I suppose, so it's not terrible.
- humanarity 12y agoAttempt at one liner: I was hoping to see a byline of "A new manned mission plan by the ESA."
- timharding 12y agoI just finished reading Dark Star — an entertaining scifi noir epic poem set on a planet with a dead sun. It isn't going to tell you about the practicalities of this type of thing but it is a good yarn. http://www.amazon.co.uk/Dark-Star-Oliver-Langmead/dp/190738930X/ref=sr_1_3?ie=UTF8&qid=1428648259&sr=8-3&keywords=dark+star http://www.amazon.co.uk/Dark-Star-Oliver-Langmead/dp/1907389...
- yCloser 12y agowhat do you mean "Free-floating planets", everything orbits something that is orbiting something
- V-2 12y agoIt takes billions of years for life to evolve. How long before a planet floating freely across the universe gets pulled into some unstable orbit or falls onto some other (bigger) celestial body
- struppi 12y ago"Atomic Rockets" has a section about "Dark Matter Planets" on their "Weird Astronomy" page. Those planets could even be heated to temperatures where liquid water can exist by exotic particles - If they are close enough to the galactic center... http://www.projectrho.com/public_html/rocket/weirdastronomy.php http://www.projectrho.com/public_html/rocket/weirdastronomy....
- ghostberry 12y ago"To have any chance of life – at least life like our own – a free-floating Earth would need liquid water. And to have liquid water, a planet needs to keep warm." Maybe, maybe not. http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Non-water_solvents http://en.wikipedia.org/wiki/Hypothetical_types_of_biochemis...
- superrad 12y agoWould such planets have a slower rate of evolution without the radiation of the sun providing mutation, or would it just be mostly contained to the development of skin?
- pavel_lishin 12y agoI would imagine that a 10km ice layer would block most interstellar radiation.
- bediger4000 12y agoThere's another scenario for life-supporting lonely planets. Caltech Astrophysicist David J. Stevenson has proposed a form of gas giant that can have a liquid water ocean: http://www.nature.com/nature/journal/v400/n6739/full/400032a0.html http://www.nature.com/nature/journal/v400/n6739/full/400032a... Looks like some follow-on work/speculation has happened, too: http://www.researchgate.net/publication/237427218_Possibility_of_Life-Sustaining_Planets_in_Interstellar_Space http://www.researchgate.net/publication/237427218_Possibilit...
- amelius 12y agoOn a much larger scale (in both space and probably time), the planet could be part of a life form (like an electron can be part of us).