# Extra Terrestrial Life **URL:** \ **Category:** Great Debates\ **Created:** [December 20, 2013, 10:47am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811 "2013-12-20T10:47:34Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [December 20, 2013, 9:28pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/21 "2013-12-20T21:28:56Z")
> [@Bryan\_Ekers](#): > > It wouldn’t have to harm us directly, just find Earth a sufficiently rich and competitor/predator-free environment to start multiplying without limit and we’ll be crowded or starved out. It’d be rabbits in Australia, cubed. There’s a series of books (Starfish, Maelstrom, Behemoth) by Peter Watts that explores this precise idea, though he uses the idea that life originated twice on Earth. The second branch of life never made the jump to living in cold seawater, and so stayed contained in a specific set of deep sea vents until people went down there. ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 21, 2013, 6:01am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/22 "2013-12-21T06:01:00Z")
> [@brazil84](#): > > I’ve got a deal for you: > > I am running a lottery. The winning ticket gets $10,000. I will sell you a billion tickets for $10. The total number of tickets (and therefore the probability of any one ticket winning) is a secret. If an unsold ticket wins, then I keep the prize money and everyone’s entry fees. > > Are you interested? It sounds like a pretty good deal, right? Even if the odds of winning are pretty low, you have a billion chances of winning, right? > > Actually I will sweeten the deal. I will sell you a trillion tickets for only $20. Now your odds of winning are a thousand times better than they would have been with only a billion tickets. How can you pass on such a great deal? Sounds pretty shady lol. Pretty sure it would cost you more than $20 just to make a trillion tickets. Do you have a point? > [@ITR\_champion](#): > > We need to consider one point while looking at this argument. It’s true that extremophiles exist. However, we’ve no reason to believe that the very first life form that ever existed on earth was an extremophile. Most likely, if that first life form came about by purely random processes, it emerged in a more “normal” environment. It replicated zillions of times. Then, in some cases, those single-celled life forms wandered to more extreme environments and evolution turned them into forms that could survive extreme heat, extreme cold, extreme radiation, etc… > > But if we imagine, for instance, a planet that was extremely hot always, or extremely radioactive, or otherwise extreme, the odds of life forming and starting to replicate on that planet would be much lower, because an “ordinary” life form that formed by random processes would be immediately zapped by the heat, radiation, … > > Our earth has many properties that make it a good place to live: an atmosphere and magnetic field that block many types of radiation while still allowing visible light from the sun, a range of temperatures that mean liquid water exists almost everywhere, a roughly circular orbit so that temperatures don’t swing all that wildly during one revolution around the sun, a relative shortage of highly radioactive elements on earth, and so forth. While we’ve settled the question of whether planets exist around other stars–they do–we have no way of know how many of those planets share all of these nice properties. This is definitely something I was trying to get at. You’re suggesting that earth only has extremophiles because they evolved from more “normal” organisms. This would mean that Earth _is_ predisposed to the proliferation of life, simply because life has already solidified it’s existence here on Earth. However, as Lemur866 has pointed out here: > [@Lemur866](#): > > Current speculation is that the first bacteria were extremophiles, who then evolved into what we think of as “normal” bacteria. > > The first bacteria were all chemosynthetic for two billion years until the evolution of photosynthesis. But there aren’t that many sources of chemical energy available compared to the density of photons coming from the Sun. So for the first two billion years the biosphere was a lot smaller and localized around sources of chemical energy–like volcanic vents. > > So it could be that bacteria had to evolve ways to live in the strange places that weren’t near-boiling sulfuric acid rather than the reverse. we _do_ have reason to believe that life doesn’t need to originate from “normal” conditions. So potentially, basic life could originate fairly easily under harsh conditions. In a global lifespan that is. > [@dracoi](#): > > There’s a series of books (Starfish, Maelstrom, Behemoth) by Peter Watts that explores this precise idea, though he uses the idea that life originated twice on Earth. The second branch of life never made the jump to living in cold seawater, and so stayed contained in a specific set of deep sea vents until people went down there. This brings up a novel idea; that life doesn’t need to only have originated from a single point. So in theory, there could be more than one tree of life on a single planet and it might even be likely depending on how easy it is for life to form initially. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [December 21, 2013, 6:58am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/23 "2013-12-21T06:58:01Z")
> [@Buck\_Godot](#): > > Further there in no reason to believe that intelligence is evolutionarily advantageous in the long term. I may be a pessimist but I doubt that civilization will still be around in 500,000 years. So even if intelligent life evolves on a given planet it may be that if you blink in geologic time you miss it. We tend to perceive intelligence (defined as the ability to use language to develop and analyse abstract concepts) as a natural consequence of evolution. Yet, it has no particular survival advantage in the context of evolution (one might even say we are at the point where we are suppressing evolution by defeating selection), so there is no reason to assume that it will arise. Realistically, planet Eden could wander all the way through Edenstar’s main sequence harboring a wondrous abundance of strange and fascinating lifeforms in a familiar range of climatescapes and never give rise to a species we could exchange ideas with. Alternately, there is no good reason to think that intelligence on Earth should not have emerged millions of years ago. Accidents happen, we seem to be one of them. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [December 21, 2013, 7:06am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/24 "2013-12-21T07:06:26Z")
> [@For You](#): > > We tend to perceive intelligence (defined as the ability to use language to develop and analyse abstract concepts) as a natural consequence of evolution. Yet, it has no particular survival advantage in the context of evolution. Say what? It’s no accident that the intelligent species dominates this planet, and has more influence over it’s biosphere and environment than all the others combined. Intelligence may not be a required endpoint of an evolutionary process, but it certainly provides a significant survival advantage. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [December 21, 2013, 7:33am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/25 "2013-12-21T07:33:40Z")
> [@ITR\_champion](#): > > Amazingly, [there are organisms that use arsenic rather than phosphorus in their DNA](http://science.nasa.gov/science-news/science-at-nasa/2010/02dec_monolake/). So life certainly can get weird. From [Wikipedia](http://en.wikipedia.org/wiki/GFAJ-1): > [@](#): > > Immediately after publication, other microbiologists and biochemists expressed doubt about this claim which was robustly criticized in the scientific community. Subsequent independent studies published in 2012 found no detectable arsenate in the DNA of GFAJ-1, refuted the claim, and demonstrated that GFAJ-1 is simply an arsenate-resistant, phosphate-dependent organism. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [December 21, 2013, 8:52am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/26 "2013-12-21T08:52:54Z")
> [@YoungKusher](#): > > Sounds pretty shady lol. Pretty sure it would cost you more than $20 just to make a trillion tickets. Not at all – each ticket has a number and I could just assign you a range of numbers. That way the tickets don’t actually need to be printed. > [@](#): > > Do you have a point? I thought the point was pretty obvious, but I will lay it out: In order to assess your chances of winning my hypothetical lottery, you need to know two things: First, how many tickets you have, and second, the probability that any one ticket will end up winning. Without both those pieces of information, it is impossible to assess your chances of winning. Even if you know that you have lots and lots of tickets. It’s the same problem with life elsewhere in the universe. To be sure, the universe is a big place. But without knowing the chances of life developing on any given planet, it’s impossible to know what the overall probabilities are. ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 21, 2013, 9:32am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/27 "2013-12-21T09:32:19Z")
> [@brazil84](#): > > Not at all – each ticket has a number and I could just assign you a range of numbers. That way the tickets don’t actually need to be printed Sure, but that’s boring. . > [@](#): > > thought the point was pretty obvious, but I will lay it out: > > In order to assess your chances of winning my hypothetical lottery, you need to know two things: First, how many tickets you have, and second, the probability that any one ticket will end up winning. Without both those pieces of information, it is impossible to assess your chances of winning. Even if you know that you have lots and lots of tickets. > > It’s the same problem with life elsewhere in the universe. To be sure, the universe is a big place. But without knowing the chances of life developing on any given planet, it’s impossible to know what the overall probabilities are. Yeah, I guess your concept was lost on me because the number I referred to when I said that, is not just the number of planets, but the number of planets that are Earth-like, or fall into the Goldilocks zone. So, unless earth is life-bearing for some reason beyond the parameters of the Goldilocks zone, I feel comfortable believing that there is other life out there. I understand that the earth’s rotation, the moon, and many many other factors go into making earth so comfy for us, but we have organisms here on Earth that would likely live on even without these stabilizers. I guess I missed the point a little bit, because if there is a winning lottery ticket at all, then doesn’t that mean that there is life out there? I’m not talking about locating this life and having the winning lottery ticket in my hand. I just have faith that there is a winning lottery ticket out there somewhere. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [December 21, 2013, 9:46am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/28 "2013-12-21T09:46:00Z")
> [@TimeWinder](#): > > Say what? It’s no accident that the intelligent species dominates this planet, and has more influence over it’s biosphere and environment than all the others combined. Intelligence may not be a required endpoint of an evolutionary process, but it certainly provides a significant survival advantage. No, not really. Without the complex language skills, we would communicate just fine, the way most social animals do, and we would survive and flourish to the same extent that they do. Evolution would continue to maintain a balanced system. Our wonderful minds have allowed us to modify the environment, and the results of that are very much not without drawbacks. We have established such a severe and apparently intractable imbalance in the global ecosystem that it very likely may start to fail to support us adequately, and humans will die off sooner than had intelligence never emerged. You may claim that it is a net positive, I will dispute that. Perhaps we can use reason to solve or contain the problems we have caused, but at this point, that looks unlikely. As smart as we are, we cannot seem to get past how smart we are. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [December 21, 2013, 10:00am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/29 "2013-12-21T10:00:14Z")
Note that we haven’t actually found one single planet that would be Earth-like enough for people to live on in shirtsleeves, despite finding more than a thousand. Part of this is an artifact of the methods we use, but we still don’t know if there are any reasonably Earth-like environments worlds in our Galaxy or elsewhere. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [December 21, 2013, 11:35am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/30 "2013-12-21T11:35:02Z")
> [@YoungKusher](#): > > Yeah, I guess your concept was lost on me because the number I referred to when I said that, is not just the number of planets, but the number of planets that are Earth-like, or fall into the Goldilocks zone. That doesn’t affect the problem I described one bit. Given that a planet “falls into the Goldilocks zone,” what is the probability of life developing there over a 1 billion year period? Evidently that probability is greater than zero and very small. Beyond that, nobody knows. Is it 1 in 1 billion? 1 in 1 trillion? 1 in a Googleplex? Without knowing more, the fact (?) that there are billions of “Goldilocks” planets is irrelevant. > [@](#): > > I guess I missed the point a little bit, because if there is a winning lottery ticket at all, then doesn’t that mean that there is life out there? Not as I constructed the analogy. In my analogy, the tickets you bought are analogous to the planets in the universe. ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 21, 2013, 12:19pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/31 "2013-12-21T12:19:44Z")
> [@brazil84](#): > > That doesn’t affect the problem I described one bit. > > Given that a planet “falls into the Goldilocks zone,” what is the probability of life developing there over a 1 billion year period? Evidently that probability is greater than zero and very small. Beyond that, nobody knows. Is it 1 in 1 billion? 1 in 1 trillion? 1 in a Googleplex? I see. Your assuming that the probability for life to form is very small. I’m assuming that it’s relatively high. Like on in a billion or one in a trillion. The extremophile tidbit serves to back this reasoning as well. > [@](#): > > Without knowing more, the fact (?) that there are billions of “Goldilocks” planets is irrelevant. So basically, if you were talking to me 10 yrs ago, when I didn’t have reason beyond shear numbers, you would be telling me that I’m just as likely to win your lottery? You may be right. I would certainly feel silly gambling my money on something when there’s no way to know my chances to win. > [@](#): > > Not as I constructed the analogy. In my analogy, the tickets you bought are analogous to the planets in the universe. I see now. The odds of life existing represent the total number of tickets because that’s how many planets there would have to be in order for one to have life, and my tickets represent how many planets there actually are. So To finally answer your question, I would definitely take your deal. I would be willing to bet that you are selling me all of the tickets and I would have to win. Very confusing to give this analogy when I’m sitting here thinking about the extremophiles, and how biased I am towards extra terrestrial life existing. Add the other topics being brought up like life possibly originating in more than one spot on earth, and I’m increasingly inclined to think that life may not be all that hard to come by. ---
**Author:** ![marshmallow](https://avatars.discourse-cdn.com/v4/letter/m/df705f/32.png) [@marshmallow](https://boards.straightdope.com/u/marshmallow)\ **Post date:** [December 21, 2013, 4:24pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/32 "2013-12-21T16:24:29Z")
Unless you’re a carbon/water chauvinist one would think Earth would be a hostile, inhabitable world full of deadly poisons for most life. As for alien microbial infections, I’d think the biggest threat would be if it was like the great oxygenation event except we play the part of the obligate anaerobes. Like if the microbes excrete chlorine gas or carbon monoxide or some other fun surprise. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [December 21, 2013, 4:53pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/33 "2013-12-21T16:53:19Z")
> [@Amateur\_Barbarian](#): > > The Kardashians? [Close](http://en.wikipedia.org/wiki/Cardassian). ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [December 21, 2013, 5:52pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/34 "2013-12-21T17:52:01Z")
> [@YoungKusher](#): > > I see. Your assuming that the probability for life to form is very small. I’m assuming that it’s relatively high. Like on in a billion or one in a trillion. Actually I’m not assuming anything. There are a couple possibilities here: First, that the probability of life developing on a planet is sufficiently low that realistically one can expect at most only one life-bearing planet. Second, that the probability of life developing on a planet is sufficiently high that one can reasonably expect numerous life-bearing planets. The point is that both possibilities are consistent with what is currently known and there is not a logical basis to prefer one over another. The fact that there may be billions of other earth-like planets does not change this conclusion. > [@](#): > > The extremophile tidbit serves to back this reasoning as well. Why? It may be that life is extraodinarily unlikely, but once it develops it’s not too hard for it to expand into extreme niches. If life is found on Earth which developed independently, that’s a different story of course. > [@](#): > > So basically, if you were talking to me 10 yrs ago, when I didn’t have reason beyond shear numbers, Well what further reason do you have? > [@](#): > > The odds of life existing represent the total number of tickets because that’s how many planets there would have to be in order for one to have life, In order to have an expectation of one additional planet with life, but basically yes. > [@](#): > > and my tickets represent how many planets there actually are. Basically yes. > [@](#): > > So To finally answer your question, I would definitely take your deal. I would be willing to bet that you are selling me all of the tickets and I would have to win. Do you want to do it for real? It would work like this: 1. You will donate $30 to a charity of my choosing. 2. I will assign you tickets number 1 through 1 trillion. 3. I will then announce “n” where the total number of tickets is 10^n 4. Starting on the next business day, we will “draw” a random number between 1 and 10^n. This will be done by choosing three digits a day. The first digit for the day will be the [digital root](http://en.wikipedia.org/wiki/Digital_root) of the closing Dow Jones Industrial Average for that day as reported by CNN Financial. The second digit will be the digital root of the NASDAQ average; and the third will be the digital root of the S & P 500. 5. After n/3 business days, we will put all of the digits in chronological order to form a whole number with n digits – the winning number. 6. If that number is between 1 and 1 trillion inclusive, then I will donate $10,000 to a charity of your choosing. Interested? ETA: And do you agree that my method of choosing a random number is acceptable? ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 22, 2013, 5:10am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/35 "2013-12-22T05:10:36Z")
> [@brazil84](#): > > The point is that both possibilities are consistent with what is currently known and there is not a logical basis to prefer one over another. The fact that there may be billions of other earth-like planets does not change this conclusion. > > Why? It may be that life is extraodinarily unlikely, but once it develops it’s not too hard for it to expand into extreme niches. > > Well what further reason do you have? Actually we do have reason to believe that life started in extreme conditions. When life formed on Earth the conditions were totally different from the way they are today. As in; no oxygen in the air, and basically a very different chemical makeup of our atmosphere. Lemur866 said: > [@](#): > > The first bacteria were all chemosynthetic for two billion years until the evolution of photosynthesis. It is logical to wonder if life has become so good at evolving through out the last few billion years, that it can adapt to live in most places, but evidence suggests that life may have more easily formed under conditions that we would think of as extreme. And, if I had the money, I would be willing to bet, that during a planets lifetime, the necessary conditions for life and thus, life itself, would occur. Once this has occurred, like is evident on our planet, that life would likely be there to stay. Assuming the entire planet isn’t destroyed by an asteroid half it’s size or something. > [@](#): > > Do you want to do it for real? > > It would work like this: > > 1. You will donate $30 to a charity of my choosing. I’m broke right now… > [@](#): > > 1. I will assign you tickets number 1 through 1 trillion. > [@](#): > > 1. I will then announce “n” where the total number of tickets is 10^n If you knew what “n” really is in relation to extra terrestrial life, then sure I would do it. You could easily just make “n” something that makes you an automatic winner. > [@](#): > > 1. Starting on the next business day, we will “draw” a random number between 1 and 10^n. This will be done by choosing three digits a day. The first digit for the day will be the [digital root](http://en.wikipedia.org/wiki/Digital_root) of the closing Dow Jones Industrial Average for that day as reported by CNN Financial. The second digit will be the digital root of the NASDAQ average; and the third will be the digital root of the S & P 500. > > 2. After n/3 business days, we will put all of the digits in chronological order to form a whole number with n digits – the winning number.{/QUOTE] > > 3. If that number is between 1 and 1 trillion inclusive, then I will donate $10,000 to a charity of your choosing. > > Interested? ETA: And do you agree that my method of choosing a random number is acceptable? I agree that your method of choosing a random number is acceptable, except for “n”. Everything revolves around “n,” so there has to be a ceiling on what “n” could be. The random number that “n” gets divided by is going to be 9 digits, or likely 222,222,222 thru 999,999,999. Also, when calculating a digital root, do you include decimals? because that also changes the odds. Basically, I automatically win or lose based on what you decide to make “n.” What method are you using to decide “n”? If I have one trillion tickets, then all you have to do is make (n\>1^22) and you automatically win. Even if you made (n\<1^22) my chances of winning would basically be dependent upon how big the first number is. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [December 22, 2013, 10:42am UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/36 "2013-12-22T10:42:26Z")
> [@YoungKusher](#): > > Actually we do have reason to believe that life started in extreme conditions. When life formed on Earth the conditions were totally different from the way they are today. As in; no oxygen in the air, and basically a very different chemical makeup of our atmosphere. Assuming that’s true, it doesn’t help your argument at all. Even if life started in extreme conditions, the probability of it having done so might be very very small. > [@](#): > > It is logical to wonder if life has become so good at evolving through out the last few billion years, that it can adapt to live in most places, but evidence suggests that life may have more easily formed under conditions that we would think of as extreme. And, if I had the money, I would be willing to bet, that during a planets lifetime, the necessary conditions for life and thus, life itself, would occur. Once this has occurred, like is evident on our planet, that life would likely be there to stay. Assuming the entire planet isn’t destroyed by an asteroid half it’s size or something. This is all irrelevant to the key question of probability. > [@](#): > > I’m broke right now… I’m pretty sure you can come up with $30. And you ought to do it for a trillion chances of winning $10,000, right? Right? > [@](#): > > If you knew what “n” really is in relation to extra terrestrial life, then sure I would do it. You could easily just make “n” something that makes you an automatic winner. Well not automatic, as you still would have a small chance of winning. But yes, I can choose “n” such that even with a trillion chances of winning, your overall likelihood of winning is arbitrarily small. And that’s the whole point: In assessing the probability of life on other worlds, we don’t know what “n” is. So the fact(?) that there are billions or trillions of Earth-like planets is insufficient to draw a conclusion about the overall likelihood of life developing on other worlds. Earlier, you said you would take my bet. I hope you see now why it’s a sucker’s bet. And the fatal flaw in your earlier statement: > [@](#): > > I’ve always believed that there has to be life beyond earth simply because of the numbers. ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 22, 2013, 12:17pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/37 "2013-12-22T12:17:04Z")
> [@brazil84](#): > > Assuming that’s true, it doesn’t help your argument at all. Even if life started in extreme conditions, the probability of it having done so might be very very small. Might be. But, life formed on Earth seemingly very early on and very quickly relatively speaking. Common belief in the scientific community is that the Earth is 4.6 billion years old. Earth doesn’t settle down enough to allow the first rocks to form until 4 billion years ago. Life is present at 3.9 billion years ago. So, from the time it takes for the first molten rock to cool to form rocks, to the time life formed is only 100 million years. Assuming life can’t exist on a planet that’s still coalescing or virtually covered in lava, that means life has existed on earth for 39/40 or 97.5% of all the time it possibly could have. That’s pretty fast, meaning it probably wasn’t that difficult for life to form here. > [@](#): > > Well not automatic, as you still would have a small chance of winning. But yes, I can choose “n” such that even with a trillion chances of winning, your overall likelihood of winning is arbitrarily small. Legitimate chance is eliminated when you give me a range of numbers. I would have to have one trillion random numbers ranging from 1 all the way to"n" to have a fair shot. You can actually choose “n” so that it is impossible for me to win. All you have to do is make n\>1^22. If you make “n” that big, when you divide 1^22 by the random 9 digit number that was procured, it will automatically be greater than one trillion. Since your only selling me tickets one through one trillion, I cannot win. You alone determine my chances of winning, if you give me a chance at all. You can calculate my exact odds of winning from 100% to 0% based on what you make “n.” > [@](#): > > And that’s the whole point: In assessing the probability of life on other worlds, we don’t know what “n” is. So the fact(?) that there are billions or trillions of Earth-like planets is insufficient to draw a conclusion about the overall likelihood of life developing on other worlds. Let me give you some numbers just to make sure it’s understood what it is I have formed my belief over. It has been determined that there are 17 billion earth-size planets in our galaxy alone. Let’s say only one percent of those are in the Goldilocks zone. This means they have the correct orbit time, distance from sun, gravity and composition. That’s 170 million. Let’s also say that only one percent of those planets have a moon that serves the same purpose as ours of balancing the Earth’s axis. That’s 1.7 million. Let us assume even further and say that only one percent of those have some other unknown missing ingredients for life. That leaves us with 17,000. Now let’s factor in that the most recent computer simulation estimates there are 500 billion galaxies in the Universe. So 17,000\*500 billion= 8.5^15=8.5 Quintilian=8500 Quadrillion=8,500,000 trillion or however you wanna say it. 8500 Quadrillion planets out there that are extremely similar to Earth. Just think about that number for a minute. > [@](#): > > Earlier, you said you would take my bet. I hope you see now why it’s a sucker’s bet. And the fatal flaw in your earlier statement: I already said I would feel silly taking the bet not knowing what "n’ is. But, for me, your logic is totally trumped by the above information I have laid out. I mean it’s only a suckers bet to me because you get to decide whether I win or lose, or at the very least get to determine my exact chances of winning. ---
**Author:** ![YoungKusher](https://avatars.discourse-cdn.com/v4/letter/y/3e96dc/32.png) [@YoungKusher](https://boards.straightdope.com/u/YoungKusher)\ **Post date:** [December 22, 2013, 12:27pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/38 "2013-12-22T12:27:37Z")
I just want to add that it has not actually been determined that there are 17 billion Earth-sized planets, it is a theory. Just clarifying for people who might object and ask for proof. However, I think we can all agree there are still a shi\* ton of em out there. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [December 22, 2013, 2:45pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/39 "2013-12-22T14:45:25Z")
> [@YoungKusher](#): > > Might be. But, life formed on Earth seemingly very early on and very quickly relatively speaking. I agree that’s interesting, but without more data it’s difficult to know how much significance to attach to this. > [@](#): > > Legitimate chance is eliminated when you give me a range of numbers. I would have to have one trillion random numbers ranging from 1 all the way to"n" to have a fair shot. You don’t seem to understand the math involved. If I choose n = 27 (and you have bought a trillion tickets), then your chances of winning are 1 in 1 quadrillion. And which numbers you choose do not affect your overall chances of winning. > [@](#): > > You can actually choose “n” so that it is impossible for me to win. No I cannot; you will always have a non-zero chance of winning. > [@](#): > > All you have to do is make n\>1^22. That makes no sense at all. 1^22 = 1. 12 \> 1. If I choose n = 12, then, you are guaranteed to win. > [@](#): > > You can calculate my exact odds of winning from 100% to 0% based on what you make “n.” To repeat, I cannot make your odds zero. If you don’t understand why, then most likely your understanding of probability theory is inadequate to understand my point. > [@](#): > > It has been determined that there are 17 billion earth-size planets in our galaxy alone. Let’s say only one percent of those are in the Goldilocks zone. This means they have the correct orbit time, distance from sun, gravity and composition. That’s 170 million. Let’s also say that only one percent of those planets have a moon that serves the same purpose as ours of balancing the Earth’s axis. That’s 1.7 million. Let us assume even further and say that only one percent of those have some other unknown missing ingredients for life. That leaves us with 17,000. Now let’s factor in that the most recent computer simulation estimates there are 500 billion galaxies in the Universe. So 17,000\*500 billion= 8.5^15=8.5 Quintilian=8500 Quadrillion=8,500,000 trillion or however you wanna say it. 8500 Quadrillion planets out there that are extremely similar to Earth. Just think about that number for a minute. Why? What is your point? Do you want 8500 quadrillion tickets for my lottery? I will sell them to you for a cool $100. > [@](#): > > I already said I would feel silly taking the bet not knowing what "n’ is. Ok, and you do not know “n” for the universe, agreed? Let’s do this: Define “n for the universe” as the number such that if you have 10^n planets other than the Earth, you can expect that life will develop on one of them. What is n for the universe? Please show your math. ---
**Author:** ![randompattern](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@randompattern](https://boards.straightdope.com/u/randompattern)\ **Post date:** [December 22, 2013, 3:08pm UTC](https://boards.straightdope.com/t/extra-terrestrial-life/676811/40 "2013-12-22T15:08:23Z")
Yea I think there’s a good chance there’s life out there. I didn’t realize there was so much math involved. Maybe it’s just a random pattern? 🙂 [Previous page](https://boards.straightdope.com/t/extra-terrestrial-life/676811.md?page=1) [Next page](https://boards.straightdope.com/t/extra-terrestrial-life/676811.md?page=3)