# Suppose we \*don't\* find alien life... **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 11, 2014, 7:19pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560 "2014-06-11T19:19:45Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [June 12, 2014, 2:09pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/41 "2014-06-12T14:09:54Z")
Prove it, based on your knowledge of future technology and scientific discoveries. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [June 12, 2014, 2:14pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/42 "2014-06-12T14:14:52Z")
You want me to prove that we won’t find intelligent life? That’s like asking me to prove that God doesn’t exist, isn’t it? ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [June 12, 2014, 2:17pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/43 "2014-06-12T14:17:54Z")
> [@Mijin](#): > > Interstellar =/= FTL > > Even chugging along at current human spacecraft speeds, a species could cross the galaxy in mere tens of millions of years, using unmanned probes or generation starships or whatever. > > If one species is dumb enough to make self-replicating probes there could be a plague of them in our galaxy in the blink of an eye relative to the galaxy’s age. > > So even with no possibility of FTL we can ask: If there’s other intelligent life in the universe, why no alien bric-a-brac in sight? It would be enormously expensive to send out even one probe, assuming it was possible with available technology, and the senders would get exactly zero benefit from doing so. Science-fiction aside, it isn’t easy to see why it woukd ever happen - let alone a sustained campaign of probes. To my mind, it is entirely possible the universe is teeming with life, but we will never know about it. ---
**Author:** ![Superhal](https://avatars.discourse-cdn.com/v4/letter/s/b4bc9f/32.png) [@Superhal](https://boards.straightdope.com/u/Superhal)\ **Post date:** [June 12, 2014, 2:24pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/44 "2014-06-12T14:24:28Z")
> [@Mijin](#): > > Hypersleep =/= sleep > > We’re not just talking about giving people a really big glass of hot milk then setting their alarm clock to AD3014. > The concept of hypersleep is that we put the body in some sort of extended stasis, maybe a particularly deep hibernation state (where body temperature and heart rate are allowed to fall significantly). Or maybe even a cryogenic stasis, with the idea of it being a “sleep” is purely figurative. I know what you mean, but we’re still talking about existing technology. The closest thing would be freezing someone but we still haven’t figured out how to avoid cellular crystallization. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [June 12, 2014, 2:24pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/45 "2014-06-12T14:24:58Z")
> [@Malthus](#): > > Science-fiction aside, it isn’t easy to see why it woukd ever happen - let alone a sustained campaign of probes. > . That’s the thing about Von Neumann machines - you only need to make one. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [June 12, 2014, 2:28pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/46 "2014-06-12T14:28:54Z")
> [@Leaffan](#): > > You want me to prove that we won’t find intelligent life? That’s like asking me to prove that God doesn’t exist, isn’t it? No, I’m asking you to set a cap on the progress of human ingenuity. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [June 12, 2014, 2:32pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/47 "2014-06-12T14:32:09Z")
> [@Alessan](#): > > That’s the thing about Von Neumann machines - you only need to make one. Yes, assuming the tech exists, but why? ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [June 12, 2014, 2:35pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/48 "2014-06-12T14:35:30Z")
> [@Alessan](#): > > No, I’m asking you to set a cap on the progress of human ingenuity. Some day we will go to Mars. We may, or may not, be able to return. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [June 12, 2014, 2:46pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/49 "2014-06-12T14:46:46Z")
> [@Malthus](#): > > Yes, assuming the tech exists, but why? Who knows? We’re talking 500 years in the future here, maybe. It could be some kid’s doctoral thesis. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [June 12, 2014, 2:57pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/50 "2014-06-12T14:57:21Z")
> [@Malthus](#): > > It would be enormously expensive to send out even one probe, assuming it was possible with available technology, and the senders would get exactly zero benefit from doing so. > > Science-fiction aside, it isn’t easy to see why it woukd ever happen - let alone a sustained campaign of probes. Erm, we’ve already sent probes out towards other star systems. And a little more than a century ago we didn’t even have fixed wing aircraft. I think there are possible arguments for why a sentient species would not send probes, but cost is not one of them. > [@](#): > > To my mind, it is entirely possible the universe is teeming with life, but we will never know about it. Yeah _possible_, of course. Teeming with _sentient_ life however, any more than a few thousand years development ahead of us…I think we would have seen some evidence of them. I think the paradox holds up here. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [June 12, 2014, 2:59pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/51 "2014-06-12T14:59:43Z")
> [@Superhal](#): > > I know what you mean, but we’re still talking about existing technology. No, we’re not. Why would we be doing that? ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [June 12, 2014, 3:32pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/52 "2014-06-12T15:32:56Z")
> [@Mijin](#): > > Erm, we’ve already sent probes out towards other star systems. And a little more than a century ago we didn’t even have fixed wing aircraft. > I think there are possible arguments for why a sentient species would not send probes, but cost is not one of them. The probes we sent were to observe our solar system and report back. That’s a clear benefit to us. They left the solar system, but that was just a by-product of their task. By the time they actually reach another star, they will be so much intert junk. The point is that sending out probes, assuming the laws of physics are as we imagine them to be, will be more or less pointless - the vast distances and huge times required to cover them pretty well insure a great disconnect between the senders and any possible recievers of information. Sending out one or two probes would of course not have any paradox-enabling effect - you have to assume some sort of massive, sustained campaign of sending these things out by the millions, for a paradox to exist. It is difficult to imagine what the point would be. The senders will never receive answers. > [@](#): > > Yeah _possible_, of course. > > Teeming with _sentient_ life however, any more than a few thousand years development ahead of us…I think we would have seen some evidence of them. I think the paradox holds up here. Unless said sentient life forms were interested in sustained campaigns of probe-sending, which strikes me as a pretty big “if”. Most activities taken by the sentient beings we know of are undertaken with some sort of expectation of gain. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 12, 2014, 3:57pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/53 "2014-06-12T15:57:07Z")
A further thought: there’s been life on Earth for ~4 billion years. That’s more than long enough for a meteor strike to have blasted some of Earth’s life into space and for it to have made the journey to another planetary system. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [June 12, 2014, 4:15pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/54 "2014-06-12T16:15:02Z")
> [@Malthus](#): > > The point is that sending out probes, assuming the laws of physics are as we imagine them to be, will be more or less pointless - the vast distances and huge times required to cover them pretty well insure a great disconnect between the senders and any possible recievers of information. Well, one point at a time. Earlier you were saying it would be “enormously expensive to send out even one probe”. That’s what I was arguing against. > [@](#): > > Sending out one or two probes would of course not have any paradox-enabling effect - you have to assume some sort of massive, sustained campaign of sending these things out by the millions, for a paradox to exist. …or probes that hop from system to system and leave some record of their being there. Or self-replicating probes. > [@](#): > > It is difficult to imagine what the point would be. The senders will never receive answers. Well that logic should apply to us too, and yet we’ve sent probes out of the solar system at the absolute earliest opportunity. Yeah, they’re not very sophisticated, and they’ll probably collapse in a heap wherever they end up in X thousand years. But it’s our first go at it. We’ve been doing this for mere decades. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [June 12, 2014, 5:37pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/55 "2014-06-12T17:37:09Z")
> [@Leaffan](#): > > Some day we will go to Mars. We may, or may not, be able to return. I think what he’s asking is to your conviction that humanity, given an indefinite amount of time and unknown progression in technology and ingenuity will _never_ reach the stars. Such an absolutist view usually comes with some good arguments you must’ve arrived at? ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [June 12, 2014, 5:44pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/56 "2014-06-12T17:44:26Z")
> [@Mijin](#): > > Well, one point at a time. Earlier you were saying it would be “enormously expensive to send out even one probe”. That’s what I was arguing against. It would be. Now multiply that by millions. > [@](#): > > …or probes that hop from system to system and leave some record of their being there. Or self-replicating probes. I suppose. But these would be even more pointless. > [@](#): > > Well that logic should apply to us too, and yet we’ve sent probes out of the solar system at the absolute earliest opportunity. Yeah, they’re not very sophisticated, and they’ll probably collapse in a heap wherever they end up in X thousand years. > But it’s our first go at it. We’ve been doing this for mere decades. We haven’t sent probes out of the solar system for the purpose of exploring distant stars - we sent probes to explore our solar system, which happen, as a function of physics, to be on trajectories that take them out of the solar system. The reason we spend all that money was to explore _our_ system, or as far as they could function, and report back. My point is that there is no obvious return for the sender to send out probes for the express purpose of exploring the universe, as the senders will not get an answer. Maybe their distant descendants will. Perhaps some species of intelligent life would consider such distant rewards worth it, but it is not entirely inconceivable that none would. For humans, exploration has generally been undertaken with the expectation of gain of some sort - if not cash money, at least scientific information or national glory. ---
**Author:** ![Kenm](https://avatars.discourse-cdn.com/v4/letter/k/bc79bd/32.png) [@Kenm](https://boards.straightdope.com/u/Kenm)\ **Post date:** [June 12, 2014, 5:45pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/57 "2014-06-12T17:45:32Z")
> [@Mijin](#): > > We’re not just talking about giving people a really big glass of hot milk then setting their alarm clock to AD3014. I’d rather die than drink hot/warm milk, from any size container. I guess I’m not boldly go material. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [June 12, 2014, 5:46pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/58 "2014-06-12T17:46:43Z")
> [@Mijin](#): > > Well that logic should apply to us too, and yet we’ve sent probes out of the solar system at the absolute earliest opportunity. Yeah, they’re not very sophisticated, and they’ll probably collapse in a heap wherever they end up in X thousand years. > But it’s our first go at it. We’ve been doing this for mere decades. Besides, who knows how long people will live in the future? Or maybe the omniscient AIs who’ll rule the planet in the year 2514 will take a longer view. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [June 12, 2014, 5:52pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/59 "2014-06-12T17:52:05Z")
> [@cmyk](#): > > I think what he’s asking is to your conviction that humanity, given an indefinite amount of time and unknown progression in technology and ingenuity will _never_ reach the stars. > > Such an absolutist view usually comes with some good arguments you must’ve arrived at? The distances are impossibly staggering to comprehend. This isn’t a journey across the Atlantic in three ships. According to [this](http://news.nationalpost.com/2014/04/17/nasa-discovers-closest-planet-to-earth-yet-this-is-the-best-case-for-a-habitable-planet/) newer article, the closest identified planet that _might possibly_ contain life is 500 light years away. That’s 500 years traveling at the fastest speed possible, according to the theory of special relativity, although time dilation would shorten that time for the people on the ship. I doubt we will ever have the possibility to travel anywhere near the speed of light, although I have no proof for this. Some [experts](http://en.wikipedia.org/wiki/Interstellar_travel#Required_energy) agree with me. > [@](#): > > The energy requirements make interstellar travel very difficult. It has been reported that at the 2008 Joint Propulsion Conference, multiple experts opined that it was improbable that humans would ever explore beyond the Solar System.[3] Brice N. Cassenti, an associate professor with the Department of Engineering and Science at Rensselaer Polytechnic Institute, stated at least the total energy output of the entire world [in a given year] would be required to send a probe to the nearest star.[3] ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [June 12, 2014, 5:52pm UTC](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560/60 "2014-06-12T17:52:34Z")
> [@Alessan](#): > > Besides, who knows how long people will live in the future? > > Or maybe the omniscient AIs who’ll rule the planet in the year 2514 will take a longer view. Or AIs could bear the long journey and using advanced biotechnology, seed a planet with life; be it using cloning, or some sort of DNA/embryo printer and artificial womb. The possibilities are endless, and the technology, while sounding far-fetched now, isn’t all that improbable extrapolating into the future. [Previous page](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560.md?page=2) [Next page](https://boards.straightdope.com/t/suppose-we-dont-find-alien-life/690560.md?page=4)