14 ms·

A Universe Full of Planets

109 points by sew 13y ago

Zikes 13y ago
I think this link will bypass the paywall: http://www.nytimes.com/2013/07/26/opinion/global/a-universe-full-of-planets.html?pagewanted=all http://www.nytimes.com/2013/07/26/opinion/global/a-universe-...
- baddox 13y ago
  Still a paywall.
  - ludwig 13y ago
    Use Chrome's incognito mode.
- Wingman4l7 13y ago
  Usually you're hitting the paywall if you see "&gwh=" in the URL and a huge string of characters after it that is presumably some sort of hash.
GuiA 13y ago
This is one of the topics that I find the most fascinating, and if I die before we learn more about life in the Universe other than on Earth, I will probably be very sad that my life span did not coincide with its discovery. There's an entire body of knowledge that we cannot chart yet because we have no data to formulate it from. It seems likely and intuitive that if there are life forms on planets other than Earth, they are subject to evolution; but we cannot hypothesize much further than that. Under what conditions does sentient meta-cognizant life evolve? How does it develop culture, religion, mathematics, art, philosophy, language? (has the Church-Turing thesis been formulated identically somewhere else than on Earth?) Which of those are constants amongst such species, and for the ones who aren't, what leads to their creation? How intertwined are they to biology? (e.g., death and religion) How frequently does the notion of "gender" happen in complex living structures? Do principles of cultural development such as the ones presented in "Guns, germs and steel" hold for non-Earth civilizations? And if we find advanced sentient life that is much older than we are, that will be even more interesting. Are there events that this civilization went through/constructs that it built that are similar to ours? (various notions of democracy/freedom/government; mechanical transportation, "computers", electricity, digital communications, artificially expanding life (i.e. healthcare), etc.) "Xenopology" is going to be one fascinating subject[1]. And on a related note, if any one is aware of serious academic work in that field (it seems pretty much impossible right now, because we just don't have the data; but you never know), I'd love to hear recommendations :) [1] With fascinating consequences when it arises, too. We'll have to rewrite a lot of the more "meta" Wikipedia articles, for starters (Wikipedia is terribly anthropo-centered). And then, what will happen with our body of knowledge? We will merge human mathematics with xenomathematics? (if it's even possible) If they have a communications construct comparable to the internet, do we keep the two separate? Do we want them to be able to communicate at all on an individual level, much like any human on Earth can email any other human on Earth freely right now? Those are all of course very hypothetic considerations, but they're probable and fascinating to think about.
- Wingman4l7 13y ago
  > Do principles of cultural development such as the ones presented in "Guns, germs and steel" hold for non-Earth civilizations? I find this particularly fascinating, because it could lead to a corollary to the Drake equation. This equation would quantify the (possibly insurmountable) barriers that a species must overcome to become a space-faring civilization: strength of the planet's gravity well, ease of access to and total planetary quantity of rare elements required to build space hardware, etc. Basically, Guns, Germs, and Steel -- but on a planetary scale.
  - TeMPOraL 13y ago
    The Great Filter - http://en.wikipedia.org/wiki/Great_Filter http://en.wikipedia.org/wiki/Great_Filter. Note some "fun" consequences of this argument: -- quote -- With no evidence of intelligent life other than ourselves, it appears that the process of starting with a star and ending with "advanced explosive lasting life" must be unlikely. This implies that at least one step in this process must be improbable. Hanson's list, while incomplete, describes the following nine steps in an "evolutionary path" that results in the colonization of the observable universe: 1. The right star system (including organics and potentially habitable planets) 2. Reproductive molecules (e.g., RNA) 3. Simple (prokaryotic) single-cell life 4. Complex (archaeatic and eukaryotic) single-cell life 5. Sexual reproduction 6. Multi-cell life 7. Tool-using animals with big brains 8. Where we are now 9. Colonization explosion. According to the Great Filter hypothesis at least one of these steps - if the list were complete - must be improbable. If it's not an early step (i.e. in our past), then the implication is that the improbable step lies in our future and our prospects of reaching step 9 (interstellar colonization) are still bleak. If the past steps are likely, then many civilizations would have developed to the current level of the human race. However, none appear to have made it to step 9, or the Milky Way would be full of colonies. So perhaps step 9 is the unlikely one, and the only thing that appears likely to keep us from step 9 is some sort of catastrophe or the resource exhaustion leading to impossibility to make the step due to consumption of the available resources (like for example highly constrained energy resources). So by this argument, finding multicellular life on Mars (provided it evolved independently) would be bad news, since it would imply steps 2–6 are easy, and hence only 1, 7, 8 or 9 (or some unknown step) could be the big problem. -- quote ends -- (emphasis mine) In other words, finding life on Mars would suggest that the Great Filter event may be ahead of us, so we're probably screwed.
Zigurd 13y ago
Why haven't they called? If planets are abundant, that puts the kibosh on the "rare Earth" theory, as shaky as that was to begin with. The other explanations are less optimistic: Maybe they all nuke themselves or turn to grey goo before they can muster the technology and energy to build a starship. Or they are roasted by random blasts of radiation before they become space-faring. It's either something universal about civilizations, or something is wrong with the Drake equation or the underlying cosmology.
- Renaud 13y ago
  Or we've been going at this for way too short a time to be able to draw definite conclusions. There are hundreds of plausible reasons why, if there is life outside, we haven't been contacted. Maybe they know about us but we're not interesting, maybe they don't know about us, maybe they tried to contact us but we haven't been able to detect them, maybe we just don't have the right technology, or we're not looking in the right place, maybe we're all limited by these pesky laws of physics and there is no chance that we could ever meet or even know about each other, maybe they are not looking in the right place and missed us, maybe they are not yet aware of our existence since we've been emitting radio for such a short time, etc
  - Zigurd 13y ago
    All those objections, have, I think, been factored in and yet the odds should be overwhelmingly in favor of life making itself known. For example "we've been going at this for way too short a time," but we know that millions to billions of stars are billions of years older than the Sun and that millions of those stars have planets. The thing about the scale of the universe is that the odds are always cosmically against "That just hasn't happened yet" being the right answer.
    - vidarh 13y ago
      > The thing about the scale of the universe is that the odds are always cosmically against "That just hasn't happened yet" being the right answer. But there are many other constraints: It may have happened many times, but they may not currently be at a level where we'd be able to communicate. We have only been emitting radio for about hundred years, and only tried to detect others for a few decades. Maybe we evolve to a point where we lose interest in being known and stop "leaking" radio signals all over the place within the next hundred. Then we're not just talking about whether or not it "has happened yet", but our interest in finding others - perhaps that'll only be a hundred year timespan - must intersect with the couple of centuries that such civilizations broadcasts hit earth, and they'd need to be in the regions of sky we've tried to detect signals from. Suddenly there can be vast number of current or past civilisations out there that'd we'd never notice.
cletus 13y ago
Like many here I find the subject of finding life on other planets fascinating and consider it inevitable. What's interesting is that the estimate of planet incidence is seemingly much higher than originally postulated by the Drake Equation [1]. A factor in the development of life, especially sentient life, is metallicity [2]. Almost all of the first 100 elements naturally occur on Earth. This is pretty amazing. Nuclear fusion in stars naturally produces elements up to iron [3]. S-capture is thought to produce elements up to Bismuth (atomic number 83). Elements higher than this are thought to be produced only in supernovae or other cataclysmic events. It's amazing to think that enough time has gone by in the Universe to take the abundant hydrogen and helium, form stars, have those stars run out of fuel and enough of them explode to scatter their elements to form heavy planets around later stars. While heavy elements may not be required for life it seems less likely that starfaring sentience can form without them. Semiconductors for example require an odd mix of heavy elements. It seems amazing that even we exist given that you need metals, a long-lived and stable star, likely billions of years of evolution, a sufficiently stable (and probably geologically active) planet with an atmosphere that has water in liquid form (a pretty narrow temperature band even taking into account different atmospheric pressures) and no cataclysmic events to happen in all that time (it seems to have been ~65 million years since the last big one). It may just be that sentient life is fleeting. We've had "civilization" for X0,000 years, which is the blink of an eye. It's entirely possible we'll wipe ourselves out due to war or simply lack of (sufficiently cheap) resources in another blink. The problem isn't lack of resources. They are plentiful in space. The problem is the cost of getting them if energy is anything other than free. Additionally interstellar distances seem almost unconquerably large that one has to wonder if we'll ever meet another sentient life form face to face (assuming they have faces). Even if we do, one wonder what evolved elsewhere for facilitate communication. Will they see? Will the wavelengths of light they see cross over ours at all? These are questions we can only really speculate about. It's also been suggested (by Hawking among others) that we really don't want to meet a much more advanced species as it will probably be bad for us, perhaps even an Outside Context Problem [4] and it seems unlikely given the rate of change we're experiencing that another civilization will be at the same point as us. We could of course be "first". I mean someone has to be right? It does seem unlikely however. But I suspect there were many "firsts" (in the sense that they evolved independently and without any contact or evidence of other species). The seeming lack of self-replicating robots, something we'll almost certainly be able to build and start filling the galaxy with within a thousand years I'm sure, is also somewhat puzzling. Personally I just hope we find evidence of extraterrestial life sometime soon as it will settle [5] a whole bunch of issues about us being "special" (in the typically religious sense). [1]: http://en.wikipedia.org/wiki/Drake_equation http://en.wikipedia.org/wiki/Drake_equation [2]: https://en.wikipedia.org/wiki/Metallicity https://en.wikipedia.org/wiki/Metallicity [3]: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/nucsyn.html#c1 http://hyperphysics.phy-astr.gsu.edu/hbase/astro/nucsyn.html... [4]: http://en.wikipedia.org/wiki/Excession#Outside_Context_Problem http://en.wikipedia.org/wiki/Excession#Outside_Context_Probl... [5]: http://xkcd.com/1235/ http://xkcd.com/1235/
dkural 13y ago
The universe never does anything just once.. black holes, gamma ray bursts, supernovae, planets, and yes, life.
RickyShaww 13y ago
Don't we know this in high school. Of course the universe is full of planets.
- grannyg00se 13y ago
  Here's the new and surprising take-away: "In other words, roughly 15 percent of all suns could, in principle, be hosting a place suitable for life as we know it. "
- vidarh 13y ago
  Unless you left high school within the last few years, no we didn't. We might have assumed, but the evidence is quite new.
vidarh 13y ago
It fascinates me to think about what this will mean to science fiction. There's obviously lots of sci fi that assumes lots of planets out there, but just like actually going to the moon means sci fi depictions of the moon "had to" align with what they actually found and it altered depictions of space ships and suits (and caused endless crappy attempts at trying to capture "low gravity"), it will increasingly "have" to deal with actual facts about what's out there.
marcosscriven 13y ago
One idea that fascinates me is the possibility of two planets in the same solar system evolving intelligent/technological life. How amazing would it have been to have been one of the first astronomers on such a planet, and see macro-structures like large cities on another planet.
- wikiburner 13y ago
  I often wonder how much more advanced our space program would have been by now had Mars or Venus been habitable.

109 points by sew 13y ago

Zikes 13y ago

I think this link will bypass the paywall: http://www.nytimes.com/2013/07/26/opinion/global/a-universe-full-of-planets.html?pagewanted=all http://www.nytimes.com/2013/07/26/opinion/global/a-universe-...

baddox 13y ago
Still a paywall.
- ludwig 13y ago
  Use Chrome's incognito mode.
Wingman4l7 13y ago
Usually you're hitting the paywall if you see "&gwh=" in the URL and a huge string of characters after it that is presumably some sort of hash.

GuiA 13y ago

This is one of the topics that I find the most fascinating, and if I die before we learn more about life in the Universe other than on Earth, I will probably be very sad that my life span did not coincide with its discovery. There's an entire body of knowledge that we cannot chart yet because we have no data to formulate it from. It seems likely and intuitive that if there are life forms on planets other than Earth, they are subject to evolution; but we cannot hypothesize much further than that. Under what conditions does sentient meta-cognizant life evolve? How does it develop culture, religion, mathematics, art, philosophy, language? (has the Church-Turing thesis been formulated identically somewhere else than on Earth?) Which of those are constants amongst such species, and for the ones who aren't, what leads to their creation? How intertwined are they to biology? (e.g., death and religion) How frequently does the notion of "gender" happen in complex living structures? Do principles of cultural development such as the ones presented in "Guns, germs and steel" hold for non-Earth civilizations? And if we find advanced sentient life that is much older than we are, that will be even more interesting. Are there events that this civilization went through/constructs that it built that are similar to ours? (various notions of democracy/freedom/government; mechanical transportation, "computers", electricity, digital communications, artificially expanding life (i.e. healthcare), etc.) "Xenopology" is going to be one fascinating subject[1]. And on a related note, if any one is aware of serious academic work in that field (it seems pretty much impossible right now, because we just don't have the data; but you never know), I'd love to hear recommendations :) [1] With fascinating consequences when it arises, too. We'll have to rewrite a lot of the more "meta" Wikipedia articles, for starters (Wikipedia is terribly anthropo-centered). And then, what will happen with our body of knowledge? We will merge human mathematics with xenomathematics? (if it's even possible) If they have a communications construct comparable to the internet, do we keep the two separate? Do we want them to be able to communicate at all on an individual level, much like any human on Earth can email any other human on Earth freely right now? Those are all of course very hypothetic considerations, but they're probable and fascinating to think about.

Wingman4l7 13y ago
> Do principles of cultural development such as the ones presented in "Guns, germs and steel" hold for non-Earth civilizations? I find this particularly fascinating, because it could lead to a corollary to the Drake equation. This equation would quantify the (possibly insurmountable) barriers that a species must overcome to become a space-faring civilization: strength of the planet's gravity well, ease of access to and total planetary quantity of rare elements required to build space hardware, etc. Basically, Guns, Germs, and Steel -- but on a planetary scale.
- TeMPOraL 13y ago
  The Great Filter - http://en.wikipedia.org/wiki/Great_Filter http://en.wikipedia.org/wiki/Great_Filter. Note some "fun" consequences of this argument: -- quote -- With no evidence of intelligent life other than ourselves, it appears that the process of starting with a star and ending with "advanced explosive lasting life" must be unlikely. This implies that at least one step in this process must be improbable. Hanson's list, while incomplete, describes the following nine steps in an "evolutionary path" that results in the colonization of the observable universe: 1. The right star system (including organics and potentially habitable planets) 2. Reproductive molecules (e.g., RNA) 3. Simple (prokaryotic) single-cell life 4. Complex (archaeatic and eukaryotic) single-cell life 5. Sexual reproduction 6. Multi-cell life 7. Tool-using animals with big brains 8. Where we are now 9. Colonization explosion. According to the Great Filter hypothesis at least one of these steps - if the list were complete - must be improbable. If it's not an early step (i.e. in our past), then the implication is that the improbable step lies in our future and our prospects of reaching step 9 (interstellar colonization) are still bleak. If the past steps are likely, then many civilizations would have developed to the current level of the human race. However, none appear to have made it to step 9, or the Milky Way would be full of colonies. So perhaps step 9 is the unlikely one, and the only thing that appears likely to keep us from step 9 is some sort of catastrophe or the resource exhaustion leading to impossibility to make the step due to consumption of the available resources (like for example highly constrained energy resources). So by this argument, finding multicellular life on Mars (provided it evolved independently) would be bad news, since it would imply steps 2–6 are easy, and hence only 1, 7, 8 or 9 (or some unknown step) could be the big problem. -- quote ends -- (emphasis mine) In other words, finding life on Mars would suggest that the Great Filter event may be ahead of us, so we're probably screwed.

Zigurd 13y ago

Why haven't they called? If planets are abundant, that puts the kibosh on the "rare Earth" theory, as shaky as that was to begin with. The other explanations are less optimistic: Maybe they all nuke themselves or turn to grey goo before they can muster the technology and energy to build a starship. Or they are roasted by random blasts of radiation before they become space-faring. It's either something universal about civilizations, or something is wrong with the Drake equation or the underlying cosmology.

Renaud 13y ago
Or we've been going at this for way too short a time to be able to draw definite conclusions. There are hundreds of plausible reasons why, if there is life outside, we haven't been contacted. Maybe they know about us but we're not interesting, maybe they don't know about us, maybe they tried to contact us but we haven't been able to detect them, maybe we just don't have the right technology, or we're not looking in the right place, maybe we're all limited by these pesky laws of physics and there is no chance that we could ever meet or even know about each other, maybe they are not looking in the right place and missed us, maybe they are not yet aware of our existence since we've been emitting radio for such a short time, etc
- Zigurd 13y ago
  All those objections, have, I think, been factored in and yet the odds should be overwhelmingly in favor of life making itself known. For example "we've been going at this for way too short a time," but we know that millions to billions of stars are billions of years older than the Sun and that millions of those stars have planets. The thing about the scale of the universe is that the odds are always cosmically against "That just hasn't happened yet" being the right answer.
  - vidarh 13y ago
    > The thing about the scale of the universe is that the odds are always cosmically against "That just hasn't happened yet" being the right answer. But there are many other constraints: It may have happened many times, but they may not currently be at a level where we'd be able to communicate. We have only been emitting radio for about hundred years, and only tried to detect others for a few decades. Maybe we evolve to a point where we lose interest in being known and stop "leaking" radio signals all over the place within the next hundred. Then we're not just talking about whether or not it "has happened yet", but our interest in finding others - perhaps that'll only be a hundred year timespan - must intersect with the couple of centuries that such civilizations broadcasts hit earth, and they'd need to be in the regions of sky we've tried to detect signals from. Suddenly there can be vast number of current or past civilisations out there that'd we'd never notice.

cletus 13y ago

Like many here I find the subject of finding life on other planets fascinating and consider it inevitable. What's interesting is that the estimate of planet incidence is seemingly much higher than originally postulated by the Drake Equation [1]. A factor in the development of life, especially sentient life, is metallicity [2]. Almost all of the first 100 elements naturally occur on Earth. This is pretty amazing. Nuclear fusion in stars naturally produces elements up to iron [3]. S-capture is thought to produce elements up to Bismuth (atomic number 83). Elements higher than this are thought to be produced only in supernovae or other cataclysmic events. It's amazing to think that enough time has gone by in the Universe to take the abundant hydrogen and helium, form stars, have those stars run out of fuel and enough of them explode to scatter their elements to form heavy planets around later stars. While heavy elements may not be required for life it seems less likely that starfaring sentience can form without them. Semiconductors for example require an odd mix of heavy elements. It seems amazing that even we exist given that you need metals, a long-lived and stable star, likely billions of years of evolution, a sufficiently stable (and probably geologically active) planet with an atmosphere that has water in liquid form (a pretty narrow temperature band even taking into account different atmospheric pressures) and no cataclysmic events to happen in all that time (it seems to have been ~65 million years since the last big one). It may just be that sentient life is fleeting. We've had "civilization" for X0,000 years, which is the blink of an eye. It's entirely possible we'll wipe ourselves out due to war or simply lack of (sufficiently cheap) resources in another blink. The problem isn't lack of resources. They are plentiful in space. The problem is the cost of getting them if energy is anything other than free. Additionally interstellar distances seem almost unconquerably large that one has to wonder if we'll ever meet another sentient life form face to face (assuming they have faces). Even if we do, one wonder what evolved elsewhere for facilitate communication. Will they see? Will the wavelengths of light they see cross over ours at all? These are questions we can only really speculate about. It's also been suggested (by Hawking among others) that we really don't want to meet a much more advanced species as it will probably be bad for us, perhaps even an Outside Context Problem [4] and it seems unlikely given the rate of change we're experiencing that another civilization will be at the same point as us. We could of course be "first". I mean someone has to be right? It does seem unlikely however. But I suspect there were many "firsts" (in the sense that they evolved independently and without any contact or evidence of other species). The seeming lack of self-replicating robots, something we'll almost certainly be able to build and start filling the galaxy with within a thousand years I'm sure, is also somewhat puzzling. Personally I just hope we find evidence of extraterrestial life sometime soon as it will settle [5] a whole bunch of issues about us being "special" (in the typically religious sense). [1]: http://en.wikipedia.org/wiki/Drake_equation http://en.wikipedia.org/wiki/Drake_equation [2]: https://en.wikipedia.org/wiki/Metallicity https://en.wikipedia.org/wiki/Metallicity [3]: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/nucsyn.html#c1 http://hyperphysics.phy-astr.gsu.edu/hbase/astro/nucsyn.html... [4]: http://en.wikipedia.org/wiki/Excession#Outside_Context_Problem http://en.wikipedia.org/wiki/Excession#Outside_Context_Probl... [5]: http://xkcd.com/1235/ http://xkcd.com/1235/

dkural 13y ago

The universe never does anything just once.. black holes, gamma ray bursts, supernovae, planets, and yes, life.

RickyShaww 13y ago

Don't we know this in high school. Of course the universe is full of planets.

grannyg00se 13y ago
Here's the new and surprising take-away: "In other words, roughly 15 percent of all suns could, in principle, be hosting a place suitable for life as we know it. "
vidarh 13y ago
Unless you left high school within the last few years, no we didn't. We might have assumed, but the evidence is quite new.

vidarh 13y ago

It fascinates me to think about what this will mean to science fiction. There's obviously lots of sci fi that assumes lots of planets out there, but just like actually going to the moon means sci fi depictions of the moon "had to" align with what they actually found and it altered depictions of space ships and suits (and caused endless crappy attempts at trying to capture "low gravity"), it will increasingly "have" to deal with actual facts about what's out there.

marcosscriven 13y ago

One idea that fascinates me is the possibility of two planets in the same solar system evolving intelligent/technological life. How amazing would it have been to have been one of the first astronomers on such a planet, and see macro-structures like large cities on another planet.

wikiburner 13y ago
I often wonder how much more advanced our space program would have been by now had Mars or Venus been habitable.