# Are we alone? **URL:** \ **Category:** Great Debates\ **Created:** [May 6, 2011, 5:07pm UTC](https://boards.straightdope.com/t/are-we-alone/580981 "2011-05-06T17:07:47Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![just\_some\_guy5](https://avatars.discourse-cdn.com/v4/letter/j/5daacb/32.png) [@just\_some\_guy5](https://boards.straightdope.com/u/just_some_guy5)\ **Post date:** [May 7, 2011, 4:55am UTC](https://boards.straightdope.com/t/are-we-alone/580981/21 "2011-05-07T04:55:10Z")
I referenced the cold war in the context of the head-on battle between the U.S. and Russia, and not “Vietnam or Afghanistan”. I won’t pretend to have been a position to know at the time, but for my money, during the Nuke race with Russia we weren’t too many standard deviations away from a full-scale global nuclear war. ---
**Author:** ![Max\_the\_Immortal](https://avatars.discourse-cdn.com/v4/letter/m/6de8d8/32.png) [@Max\_the\_Immortal](https://boards.straightdope.com/u/Max_the_Immortal)\ **Post date:** [May 7, 2011, 5:38am UTC](https://boards.straightdope.com/t/are-we-alone/580981/22 "2011-05-07T05:38:38Z")
Most right-thinking people wouldn’t dismiss out of hand the notion that at one point, billions of years ago, the sum total of life on Earth was a small collections of crude single-celled organisms that could fit into a teaspoon as easily as you or I could fit into a football stadium. But the Earth was so _huge_, it would have been an awful waste of space to have a teaspoon of life on an otherwise barren rock, right? Fast forward to today. The globe is absolutely infested with living things. You can’t inhale without sucking in a bunch of spores. And it call came from the Primordial Ooze. It’s remarkable, really. Suppose that the rest of the universe is barren. That the sum total of life in the universe can fit onto a single planet as easily as you or I could fit into a football stadium. Suppose that, billions of years in the future, the universe is infested with life descended from the life on Earth today (whether spread by people deliberately setting up colonies or by [more ignoble means](http://www.youtube.com/watch?v=kndxsByVscA&t=160)). Could people living in that future find is as plausible that all life in the universe originated from a single planet as we can find it plausible that all life on Earth originated from a microscopic clump of bacteria? Now, ask yourself which is a more egotistical attitude: A) That we are so close to the pinnacle of the complexity of life that all across the universe billions upon billions of planets have independently given rise to organisms that, all things considered, are pretty much just like us? Or B) That in the grand scheme of things, we aren’t that far removed from the Primordial Ooze? ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 7, 2011, 6:48am UTC](https://boards.straightdope.com/t/are-we-alone/580981/23 "2011-05-07T06:48:43Z")
> [@gonzomax](#): > > Food farm. When we get enough people, they will come and harvest. No way. If they were raising us, they’d have come and clean out our cage already. We’ve certainly fouled it enough. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 7, 2011, 6:51am UTC](https://boards.straightdope.com/t/are-we-alone/580981/24 "2011-05-07T06:51:50Z")
> [@JohnT](#): > > No. It was a lot of slaves. And they didn’t have “physical god like powers” either… they were just people, like you and me. > > And, personally, imho, implying that the Egyptians/Mayans needed help piling bricks together in a pyramid shape really insults the Egyptians and Mayans. Now if they had built a sub-space communicator, then we’d have a right to question it. But block-piling technology and theory isn’t all that advanced - a 2 year old can do it. The pyramids weren’t built by slaves, they were built by draftees. Their villages have been found. And, if you visit, they will tell you how they were built. They piled up sand as they built them higher, and dragged the stones up the sand ramp. ---
**Author:** ![New\_Deal\_Democrat](https://avatars.discourse-cdn.com/v4/letter/n/9d8465/32.png) [@New\_Deal\_Democrat](https://boards.straightdope.com/u/New_Deal_Democrat)\ **Post date:** [May 7, 2011, 7:32am UTC](https://boards.straightdope.com/t/are-we-alone/580981/25 "2011-05-07T07:32:26Z")
I think there is life on other planets, and civilizations on some of them. Nevertheless, the distances involved mean that intelligent life forms have rarely if ever visited out planet. Because of those distances life forms visiting us would have done so at great effort and sacrifice. They probably would have made their visits obvious. They have not. That leads me to suspect that they have not visited. If any advanced civilizations exist within a few hundred light years of earth we probably would have detected radio broadcasts from them. We have not. ---
**Author:** ![Rachellelogram](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rachellelogram/32/8689_2.png) [@Rachellelogram](https://boards.straightdope.com/u/Rachellelogram)\ **Post date:** [May 7, 2011, 8:02am UTC](https://boards.straightdope.com/t/are-we-alone/580981/26 "2011-05-07T08:02:21Z")
If we are, it seems like an awful waste of space. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [May 7, 2011, 10:02am UTC](https://boards.straightdope.com/t/are-we-alone/580981/27 "2011-05-07T10:02:49Z")
> [@New\_Deal\_Democrat](#): > > If any advanced civilizations exist within a few hundred light years of earth we probably would have detected radio broadcasts from them. We have not. I don’t think that’s true. From memory, I think we could detect a powerful radio signal beamed at us from a considerable distance, but not background noise of a planet going about it’s normal business. > [@FarmerChuck](#): > > Are we alone? Very probably not I’d say, but unless intelligent life is very common in the universe we are unlikely to ever meet ET or even receive a signal. There are only a handful of stars within 10 light years of us. > [@FarmerChuck](#): > > 1. Have aliens visited us? i think so i mean if there is an advanced civilization out there somewhere watching us… (there has to be) and they start recoreding nuclear bombs going off dont u think ud pop in for an look see? This assumes that anyone is close enough to look and has the means to travel over interstellar distances, which I’d rate as very improbable. > [@FarmerChuck](#): > > 1. why did we stop after getting to the moon, why has every other country not really tried? Because of huge expense and no compelling reason to go. It’s much cheaper to send a probe if you want to explore the moon more. The same argument applies for exploring Mars. A manned mission would be scientifically worthwhile, but you could fund an awful lot of space probes for the same money. > [@FarmerChuck](#): > > 1. are we going to be on this rock forever? why is going farther not a national debate i mean where is the christopher columbus of our day? We are stuck here for the foreseeable future. Columbus only needed to find investors for a few ships and their crews to go exploring. It would take the wealth of nations for us to take the next step out into space. It’s currently far beyond our capabilities to establish a self-sustaining colony on another planetary body. ---
**Author:** ![nachtmusick](https://avatars.discourse-cdn.com/v4/letter/n/ac91a4/32.png) [@nachtmusick](https://boards.straightdope.com/u/nachtmusick)\ **Post date:** [May 7, 2011, 10:33am UTC](https://boards.straightdope.com/t/are-we-alone/580981/28 "2011-05-07T10:33:21Z")
There must be life elsewhere; it stands to reason. The physics we know dictate that there is no conceivable way that such life can interact with us. The distances and time scales overwhelm not only hope, but fantasy as well. So we either insist that our scientists develop less melancholy science, or we learn to live on this one single planet. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [May 7, 2011, 11:01am UTC](https://boards.straightdope.com/t/are-we-alone/580981/29 "2011-05-07T11:01:10Z")
> [@nachtmusick](#): > > The physics we know dictate that there is no conceivable way that such life can interact with us. The distances and time scales overwhelm not only hope, but fantasy as well. Maybe somewhere in the universe intelligent life will independantly develop at two stars close enough to interact with each other. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [May 7, 2011, 11:12am UTC](https://boards.straightdope.com/t/are-we-alone/580981/30 "2011-05-07T11:12:38Z")
> [@nachtmusick](#): > > The physics we know dictate that there is no conceivable way that such life can interact with us. The distances and time scales overwhelm not only hope, but fantasy as well. Actually, the immense time scales tell us that we should _expect_ to interact with some other form of life – basically, if we started now, we could colonize every planet in the galaxy within about 5 to 50 million years, which, cosmologically speaking, is barely a moment. Taking into account that the universe has been conducive to life for at least a couple of billion years (i.e. since enough heavy elements for some serious chemistry were sufficiently well distributed), 200-400 billion star systems alone in our galaxy, there’s a real question as to why apparently within not one of them a civilization has evolved that has undertaken this quest during the last some hundred million years or so; this is what’s known as the Fermi paradox. There’s a number of possible resolutions to it (my favourite perhaps being the one by Hungarian Leo Szilard who, after Fermi had proposed the paradox, apparently quipped: “Oh, but they _are_ here. They just call themselves Hungarians!”), with a relatively recent one proposing that [natural selection acts on cosmological scales](http://www.technologyreview.com/blog/arxiv/26622/) – and that civilizations that advertise their presence are strongly selected against… 😛 ---
**Author:** ![nachtmusick](https://avatars.discourse-cdn.com/v4/letter/n/ac91a4/32.png) [@nachtmusick](https://boards.straightdope.com/u/nachtmusick)\ **Post date:** [May 7, 2011, 12:20pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/31 "2011-05-07T12:20:06Z")
> [@Alka\_Seltzer](#): > > Maybe somewhere in the universe intelligent life will independantly develop at two stars close enough to interact with each other. Perhaps, but not in the outskirts of the Sagittarius Arm. ---
**Author:** ![astorian](https://avatars.discourse-cdn.com/v4/letter/a/ad7895/32.png) [@astorian](https://boards.straightdope.com/u/astorian)\ **Post date:** [May 7, 2011, 1:03pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/32 "2011-05-07T13:03:48Z")
> [@rachelellogram](#): > > If we are, it seems like an awful waste of space. Carl Sagan’s line. Cute, but silly, really. “Waste” would only be an issue if we suppose there’s a God creating everything. If there IS, you could ask Him, with some justice, why he’d made such a vast universe and only put intelligent life on one measly planet. But if you’re an atheist, as Sagan professed to be, why WOULDN’T there be intelligent life on one tiny planet and absolutely nothing anywhere else? If the universe (like everything in it) is just a random thing, the emergence of life COULD be a longshot, and infinite strecthes of nothingness wouldn’t be a “waste”- just a plausible, logical result of a pointless, meaningless Big Bang. ---
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [May 7, 2011, 1:29pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/33 "2011-05-07T13:29:37Z")
> [@nachtmusick](#): > > Perhaps, but not in the outskirts of the Sagittarius Arm. Very probably not, but we don’t really know enough to make decent estimates on many of the parameters in the drake equation. I expect we’ll make some progress on this during my lifetime. Examining other bodies in the solar system will give us a better idea of how likely it is that life will arise, and by performing a a more through survey of nearby planetary systems. ---
**Author:** ![fumster](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@fumster](https://boards.straightdope.com/u/fumster)\ **Post date:** [May 7, 2011, 3:19pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/34 "2011-05-07T15:19:17Z")
The way I look at it there is either one intelligent species that has walked on earth or none. Your post inclines me towards the latter view. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [May 7, 2011, 5:30pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/35 "2011-05-07T17:30:23Z")
> [@Chronos](#): > > It’s also not rational to disbelieve things for which there is an abundance of evidence. We don’t have evidence for any _particular_ alien civilization, but the Universe is so incredibly vast that statistically, the chances are overwhelmingly in favor of ETs _somewhere_ out there. I, for one, am agnostic about the existence of intelligent life elsewhere in the universe. “The Universe is so incredibly vast” is not, by itself, a conclusive argument. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 7, 2011, 5:50pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/36 "2011-05-07T17:50:48Z")
Are we alone? Almost certainly not. If the probability of intelligent life developing on a planet is p, and it not (1-p) (1-p)\*\*n is very small if n is very large. N here is the number of planets on which life can develop, which is looking bigger and bigger. Of course p must be \> 0, but we know it is since we’re here. There are plenty of reasons for advanced cultures to not contact us even if they could. Given what happened on Earth when “advanced” cultures contact less advanced ones, any ethical race would stay far away until we matured a bit more. Perhaps when we reach Alpha Centauri we’ll find them there to greet us- not because they live there, but because we passed a test. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [May 7, 2011, 6:10pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/37 "2011-05-07T18:10:57Z")
> [@Voyager](#): > > Are we alone? Almost certainly not. If the probability of intelligent life developing on a planet is p, and it not (1-p) (1-p)\*\*n is very small if n is very large. N here is the number of planets on which life can develop, which is looking bigger and bigger. Of course p must be \> 0, but we know it is since we’re here. “Very large” is relative. Mathematically, if p is small _enough_ (a possibility which I don’t know enough to rule out), n would have to be well over the number of planets in the universe for (1-p)\*\*n to be very small. That’s why I don’t feel safe saying “almost certainly not.” ---
**Author:** ![New\_Deal\_Democrat](https://avatars.discourse-cdn.com/v4/letter/n/9d8465/32.png) [@New\_Deal\_Democrat](https://boards.straightdope.com/u/New_Deal_Democrat)\ **Post date:** [May 7, 2011, 6:27pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/38 "2011-05-07T18:27:56Z")
> [@Alka\_Seltzer](#): > > I don’t think that’s true. From memory, I think we could detect a powerful radio signal beamed at us from a considerable distance, but not background noise of a planet going about it’s normal business. A radio telescope pointed at a near by star would pick up the kind of television and FM radio broadcasts we have been transmitting for about sixty ears. The SETI (Search for Extraterrestrial Intelligence) Institute has been scanning the skys since 1992 without finding credible evidence of intelligent life. > **[Home](https://www.seti.org/)** ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [May 7, 2011, 7:02pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/39 "2011-05-07T19:02:35Z")
I think we’re probably not alone, but one thing to bear in mind is that the chances of life spontaneously occurring may be 1 in trillions. It’s one of very few natural phenomena we can’t directly replicate, and unless we can we won’t be able to figure out how likely it is to occur. ---
**Author:** ![marshmallow](https://avatars.discourse-cdn.com/v4/letter/m/df705f/32.png) [@marshmallow](https://boards.straightdope.com/u/marshmallow)\ **Post date:** [May 7, 2011, 7:16pm UTC](https://boards.straightdope.com/t/are-we-alone/580981/40 "2011-05-07T19:16:52Z")
> [@Chronos](#): > > It’s also not rational to disbelieve things for which there is an abundance of evidence. Are you saying there’s abundant evidence for extraterrestrials? The only thing I can think of is that Martian meteor, but I thought that was either the result of geologic processes or inconclusive. > [@](#): > > We don’t have evidence for any _particular_ alien civilization, but the Universe is so incredibly vast that statistically, the chances are overwhelmingly in favor of ETs _somewhere_ out there. There’s as much evidence for that as the position that life is so improbable that it has risen exactly once in the entire universe. The latter has the benefit of being a lot easier to falsify than the former, since all we need to do is find a single counter-example. I like to think there are aliens too, but it’s not rational. I file that under the Rule of Cool. [Previous page](https://boards.straightdope.com/t/are-we-alone/580981.md?page=1) [Next page](https://boards.straightdope.com/t/are-we-alone/580981.md?page=3)