# Given Another 100 Million years, What Are The Chances That I Will Exist Again? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 19, 2015, 3:08pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267 "2015-08-19T15:08:23Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [August 19, 2015, 3:08pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/1 "2015-08-19T15:08:23Z")
I mean, is there a finite probability that someone with my eyes, body type, , etc. will be born sometime in the future? Or are humans so unique that there will never be a copy of me? ---
**Author:** ![JerrySTL](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@JerrySTL](https://boards.straightdope.com/u/JerrySTL)\ **Post date:** [August 19, 2015, 3:17pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/2 "2015-08-19T15:17:36Z")
With evolution I doubt that there will even be any Homo Sapiens. ---
**Author:** ![Koxinga](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@Koxinga](https://boards.straightdope.com/u/Koxinga)\ **Post date:** [August 19, 2015, 3:20pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/3 "2015-08-19T15:20:12Z")
See Nietzsche and [Eternal Recurrence](https://en.wikipedia.org/wiki/Eternal_return#Friedrich_Nietzsche). ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [August 19, 2015, 9:19pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/4 "2015-08-19T21:19:43Z")
Given seven billion people, I’ll bet a couple Euros that there already is someone here that is amazingly like you. Someone who looks like you, sounds like you, and thinks a lot like you. I’ve met such “fetches” of a number of my friends. It’s wonderfully eerie! So…what degree of resemblance do you demand? If you insist on identity, right down to the individual atoms, then, no, 100 million years (and one planet) isn’t long enough. Up it to 20 billion years, and the observed cosmos (and possibly other cosmoi similar to ours!) and I won’t place the bet. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [August 19, 2015, 10:17pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/5 "2015-08-19T22:17:31Z")
If exactly, zero. Why would there be someone exactly like you? ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [August 19, 2015, 10:42pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/6 "2015-08-19T22:42:13Z")
Well, there are identical twins. And if you believe certain speculative theories about multiverses, there are infinite copies of you already running around out there right now. Ignoring that: There must be some finite number of combinations of genes. So how many humans do you have to run through before you can expect a duplicate? Apparently, something like 99.5 percent of our genes go into just making us human. So any individual variation must be down to the last 0.5 percent. Doesn’t sound like all that much. I am in no way smart enough, nor do I know enough about genetics or math, to figure this out. So I googled it. Which didn’t get me very far. The consensus seems to be some variation of “lots and lots and lots”. Beyond that, no one seems to agree. [This](http://boards.straightdope.com/sdmb/showthread.php?t=1241) ancient thread on this board was no help at all. At the end of the day, I decided to settle for [this](http://www.quora.com/If-DNA-uniquely-describes-a-person-how-many-different-humans-can-be-produced-theoretically): > [@quora link](#): > > Although there are 4 billion base pairs, most of them go into just making you human. Most of the possibilities aren’t just non-viable; they’re not even organisms. > > Humans are about 99.5% similar. You could actually modify a fair bit of the rest of the DNA without killing somebody and in fact have them still be recognizably human (and perfectly healthy), but let’s come up with a low end. > > That’s still 4^(.005\*3.2 billion) ≈6×109632959 I believe that is what the kids call a big-ass number. So… I don’t think the chances are great. ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [August 19, 2015, 10:49pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/7 "2015-08-19T22:49:23Z")
Oops, quote got screwed up. That should be: 6×10^9632959. Big-ass number. ---
**Author:** ![Arrogance\_Ex\_Machina](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/arrogance_ex_machina/32/192_2.png) [@Arrogance\_Ex\_Machina](https://boards.straightdope.com/u/Arrogance_Ex_Machina)\ **Post date:** [August 19, 2015, 10:52pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/8 "2015-08-19T22:52:16Z")
It probably depends on your racial background as well, that is how average-looking you are to begin with. If you take me for example - I’m 100% Finnish with both sides of my family tree going way back here in Finland. So I look fairly typical for a Finn if you ignore my height (I’m 6’6) and the chances there’s somebody looking like me in Finland (and to some extent in Sweden or Estonia) are fairly good. But if you have an exotic set of parents like one from Finland and another from Japan the odds are a lot lower there’s anybody even remotely like you. You’ll still never get an exact copy, though. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [August 19, 2015, 11:28pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/9 "2015-08-19T23:28:13Z")
It is likely that within only 10^125 light years there is a planet just like earth and a copy of you (and me and all the rest) is there. ---
**Author:** ![TonySinclair](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@TonySinclair](https://boards.straightdope.com/u/TonySinclair)\ **Post date:** [August 19, 2015, 11:32pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/10 "2015-08-19T23:32:17Z")
Pick out some dinosaur that lived 100 million years ago. What are the odds of his exact duplicate existing today? ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [August 19, 2015, 11:34pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/11 "2015-08-19T23:34:49Z")
> [@TonySinclair](#): > > Pick out some dinosaur that lived 100 million years ago. What are the odds of his exact duplicate existing today? I saw a documentary about that called “Jurassic Park”. Conclusion: In 100 million years, \*\*ralph \*\*will be part frog. ---
**Author:** ![TonySinclair](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@TonySinclair](https://boards.straightdope.com/u/TonySinclair)\ **Post date:** [August 19, 2015, 11:36pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/12 "2015-08-19T23:36:40Z")
> [@Hari\_Seldon](#): > > It is likely that within only 10^125 light years there is a planet just like earth and a copy of you (and me and all the rest) is there. It’s likely that there is an earth-like planet, in the sense that it would support terrestrial life. The chance is statistically zero that it would be identical to earth, even if you’re only talking about the exact size and shape of land and sea. To say it would have human life, let alone duplicates of “all the rest” of life on earth, is absurd, although it might have some form of intelligent life. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [August 20, 2015, 3:44pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/13 "2015-08-20T15:44:34Z")
One theory I’ve heard, and who knows if it is wishful thinking but seeing how fast technology advances you really can’t predict the long term future, is that sometime in the future we will learn how to reassemble the information that was behind subjective consciousness, and this will allow conscious life forms to live again long after dying if they choose to. Kind of like the robot last judgement where they ask if you want to live again or not. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 20, 2015, 4:34pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/14 "2015-08-20T16:34:59Z")
> [@Martian Bigfoot](#): > > I saw a documentary about that called “Jurassic Park”. > > Conclusion: In 100 million years, \*\*ralph \*\*will be part frog. On the internet, nobody knows whether he’s part frog or not. From some of his posts though … Just kidding. No offense meant. 🙂 ---
**Author:** ![Doctor\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doctor_jackson/32/32_2.png) [@Doctor\_Jackson](https://boards.straightdope.com/u/Doctor_Jackson)\ **Post date:** [August 20, 2015, 6:01pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/15 "2015-08-20T18:01:03Z")
> [@Martian Bigfoot](#): > > And if you believe certain speculative theories about multiverses, there are infinite copies of you already running around out there right now. No wonder I’m so damned tired… ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [August 20, 2015, 9:12pm UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/16 "2015-08-20T21:12:32Z")
> [@TonySinclair](#): > > It’s likely that there is an earth-like planet, in the sense that it would support terrestrial life. The chance is statistically zero that it would be identical to earth, even if you’re only talking about the exact size and shape of land and sea. To say it would have human life, let alone duplicates of “all the rest” of life on earth, is absurd, although it might have some form of intelligent life. I’m too lazy to do the math…but… I can buy that there’s an earth-like planet, that has two major oceans and four major continents, even that they look much like Asia, Africa, North and South America, there’s one big Moon just close enough for perfect eclipses, and there’s DNA based life there. I stop believing when you add that the DNA code is the exact same as the DNA code we use. That’s just one detail too much for credibility. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [August 21, 2015, 7:10am UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/17 "2015-08-21T07:10:51Z")
> [@Trinopus](#): > > I’m too lazy to do the math…but… I can buy that there’s an earth-like planet, that has two major oceans and four major continents, even that they look much like Asia, Africa, North and South America, there’s one big Moon just close enough for perfect eclipses, and there’s DNA based life there. > > I stop believing when you add that the DNA code is the exact same as the DNA code we use. That’s just one detail too much for credibility. Me too. Unless we live in an infinite universe. Then there are infinite numbers of planet earth. I took your position and got smacked down [here](http://boards.straightdope.com/sdmb/showthread.php?t=637765). Unfortunately it didn’t sink in, so the point had to be driven home in a later thread which I can’t seem to find. ---
**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\ **Post date:** [August 21, 2015, 8:14am UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/18 "2015-08-21T08:14:13Z")
> [@Martian Bigfoot](#): > > Oops, quote got screwed up. > > That should be: 6×10^9632959. Big-ass number. To put this in perspective, the estimated number of atoms in the universe is only 10[sup]80[/sup]. The observable universe is only 8.8x10[sup]6[/sup] meters in diameter. 6x10[sup]9632959[/sup] is an _unimaginably_ huge number. And that’s just how many potential DNA patterns there are. Assuming you hit the jackpot and manage to get someone with your exact DNA - now to make a new you, they still need to be exposed to the same environment in the womb, the same environment outside of the womb, suffer the same injuries and illnesses… (And this is just assuming an exact (to the point that can be reasonably, practically, humanly measured) physical match…an exact mental match would be harder still.) You could, fairly easily, get somebody who could be mistaken for you at a casual look, or even superficial examination. But somebody who’s an exact match in all measurable physical parameters is _theoretically_ possible, but so vanishingly unlikely as to be _practically_ impossible. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [August 21, 2015, 10:52am UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/19 "2015-08-21T10:52:56Z")
The observable universe is (8.8 times 10 to the 26th power) meters in diameter, not to the 6th power: > **[Observable universe](https://en.wikipedia.org/wiki/Observable_universe)** > > The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. There may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on dat The w... ---
**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\ **Post date:** [August 21, 2015, 11:23am UTC](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267/20 "2015-08-21T11:23:56Z")
Oops. And I proofread that several times, too. [Next page](https://boards.straightdope.com/t/given-another-100-million-years-what-are-the-chances-that-i-will-exist-again/728267.md?page=2)