# \*My\* theory on alien life and our planets place in the galaxy **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 26, 2020, 1:12pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388 "2020-07-26T13:12:27Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 27, 2020, 7:57pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/21 "2020-07-27T19:57:46Z")
Here’s a theory backed up with evidence. The universe is full of intelligent races but they never meet each other because the universe is really big and we can’t travel faster than the speed of light. Intelligent species are all pretty much stuck in the solar system they evolved in. ---
**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\ **Post date:** [July 27, 2020, 8:17pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/22 "2020-07-27T20:17:00Z")
> [@Little\_Nemo](#): > > Here’s a theory backed up with evidence. The universe is full of intelligent races but they never meet each other because the universe is really big and we can’t travel faster than the speed of light. Intelligent species are all pretty much stuck in the solar system they evolved in. Pretty much what that crusty old giant of evolutionary biology Ernst Mayr expressed in Towards a New Philosophy of Biology. Or more pointedly, even if they aren’t stuck in their solar system entirely, the odds of a technologically advanced alien society and human society co-existing within a temporal framework that would make contact possible in absence of some sci-fi light+ speed travel is incredibly low. I think the evolution of life somewhere out there is likely. We’re talking about a huge galaxy and I think if anything close to the Oparin Hypothesis is correct it shouldn’t be that crazily difficult. Sapience? Well, who knows how unlikely that is. But hard contact? Insanely, astronomically (heh) unlikely. In the incredibly remote chance SETI ever did scare up something it would just be the reflections from thousands of years ago of someone long dead. ---
**Author:** ![Pavelb1](https://avatars.discourse-cdn.com/v4/letter/p/439d5e/32.png) [@Pavelb1](https://boards.straightdope.com/u/Pavelb1)\ **Post date:** [July 27, 2020, 8:59pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/23 "2020-07-27T20:59:51Z")
Also this sapience would really find it handy (heh) to have some sort of manual abilities. Dolphins could be smart as hell…but they aint building a ship with snouts. Octopi have it going on there but…I’m sure there are some sort of evolutionary pressures at play. And hell… …Maybe curiosity is super-rare too. Man is really good in the curiosity department and in the ‘need for approval/serotnin rush’ department. But now im really rambling. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [July 27, 2020, 10:35pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/24 "2020-07-27T22:35:37Z")
> [@Pavelb1](#): > > Also this sapience would really find it handy (heh) to have some sort of manual abilities. Dolphins could be smart as hell…but they aint building a ship with snouts. Octopi have it going on there but…I’m sure there are some sort of evolutionary pressures at play. And hell… Dolphins may well be building ships soon enough. With their opposable thumbs. > **[Dolphins Evolve Opposable Thumbs](https://www.theonion.com/dolphins-evolve-opposable-thumbs-1819565718)** > > HONOLULU–In an announcement with grave implications for the primacy of the species of man, marine biologists at the Hawaii Oceanographic Institute reported Monday that dolphins, or family Delphinidae, have evolved opposable thumbs on their pectoral... ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [July 27, 2020, 10:58pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/25 "2020-07-27T22:58:22Z")
> [@Little\_Nemo](#): > > Here’s a theory backed up with evidence. The universe is full of intelligent races but they never meet each other because the universe is really big and we can’t travel faster than the speed of light. Intelligent species are all pretty much stuck in the solar system they evolved in. We don’t know how long aliens live. The beings on Capella 4 may see a 10,000-year trip as an opportunity to binge watch and nap. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [July 27, 2020, 11:25pm UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/26 "2020-07-27T23:25:18Z")
> [@Projammer](#): > > **11. Earth is deliberately not being contacted.** On Earth, we have policies about contacting indigenous peoples; it’s possible that the same thing could be happening with us. Advanced alien societies may enforce rules that limit contact only to species that attain a lofty degree of technological or cultural evolution. That’s quite a directive, that prime directive. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 28, 2020, 12:07am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/27 "2020-07-28T00:07:01Z")
> [@coffeecat](#): > > We don’t know how long aliens live. The beings on Capella 4 may see a 10,000-year trip as an opportunity to binge watch and nap. It’s unlikely. A species that would consider ten thousand years as an insignificant amount of time would have to have a lifespan of over a million years. If a species has a million year lifespan, they’re either going to have an equivalently long breeding cycle. If they don’t have their first offspring until a hundred thousand years or more after birth, natural selection and evolution will be an incredibly slow process. The human race is about ten thousand generations old. Ten thousand generations for this theoretical long-living race would be about a billion years. And humans didn’t just appear. We’re a link in a chain of prior species. Our long-living aliens must be the descendants of long-living animals. When would all of this evolution from single-celled organisms to space-traveling intelligent beings have occurred? The universe is only around thirteen billion years old. Perhaps you’re suggesting these aliens have incredibly long lifespans but don’t have comparable breeding cycles. Maybe they start having offspring within a few years after birth. And then what? They continue have offspring for hundreds of millennia? Any species which did that would collapse from over-population. Their long-living animal ancestors would have gone extinct before evolving into an intelligent species. But let’s wave all that away and just say it happens. They’re an incredibly long-living intelligent race that exists somehow. We still wouldn’t see them. I mentioned before how the universe is really big. Let me be clearer; the universe is really really really really really really really really really really big. That long living intelligent alien that’s been traveling for ten thousand years? He’s not even a fraction of the way here yet. Let’s say by an amazing coincidence, he happens to be in the same galaxy we’re in. And let’s say he’s only halfway across this galaxy away from us. Assuming he’s traveling at the speed of light (which is impossible) he’s going to need a hundred thousand years to reach us. And assuming this alien is in one of the other hundreds of billions of galaxies in the universe, he’ll never get here. The “local” group of galaxies (which contains over fifty galaxies) is over twenty million light years across. So even if this alien is here in the intergalactic neighborhood and is moving along at the speed of light, he won’t show up for millions of years. ---
**Author:** ![Blue\_Blistering\_Barnacle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_blistering_barnacle/32/3386_2.png) [@Blue\_Blistering\_Barnacle](https://boards.straightdope.com/u/Blue_Blistering_Barnacle)\ **Post date:** [July 28, 2020, 12:24am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/28 "2020-07-28T00:24:18Z")
I’m not an expert on this, so technical input would help- Isn’t it true that we only see a fraction of planetary systems out there? We are not looking in all directions. The first methods of detection (Doppler shift) favored detection of giant planets with short orbital periods. These have to have orbital planes more or less aligned with us. Occultation is better, but also favors detection of large planets. These MUST have orbital planes aligned with us. I had thought that detecting ANY earth- sized planets in habitable zone (I think we’ve detected at least one) was pretty good. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 28, 2020, 12:36am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/29 "2020-07-28T00:36:37Z")
So when are they going to build this hyperspace bypass I keep hearing about? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2020, 1:29am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/30 "2020-07-28T01:29:03Z")
> [@Blue\_Blistering\_Barnacle](#): > > I’m not an expert on this, so technical input would help- > > Isn’t it true that we only see a fraction of planetary systems out there? > > We are not looking in all directions. > > The first methods of detection (Doppler shift) favored detection of giant planets with short orbital periods. These have to have orbital planes more or less aligned with us. > > Occultation is better, but also favors detection of large planets. These MUST have orbital planes aligned with us. All that is true, and none of it relevant to the fact we haven’t found a single especially Earthlike planet. The random alignment of the exo-planetary systems relative to our own gives us a random sample of what is out there. And _thousands_ of known planets seems like a pretty good sample size to give us a pretty good idea of what types of planets we should find in systems that aren’t aligned correctly or are in a different patch of the sky. If our sampling shows that Earthish planets must be Pretty Damn Rare for the thousands of stars we have looked at, it is pretty likely that they are equally Pretty Damn Rare for the rest of the stars of that type that we haven’t looked at. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2020, 1:34am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/31 "2020-07-28T01:34:50Z")
Before we actually started discovering planets, some models of planetary formation claimed that our arrangement was typical, with small rocky planets close to the star and large gas giants far out. But the actual observations show pretty much any type of planet at pretty much any distance. So having a planet of the right size and the right composition at the right distance from the right type of star is a random roll of a whole handful of dice. ---
**Author:** ![Blue\_Blistering\_Barnacle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_blistering_barnacle/32/3386_2.png) [@Blue\_Blistering\_Barnacle](https://boards.straightdope.com/u/Blue_Blistering_Barnacle)\ **Post date:** [July 28, 2020, 1:57am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/32 "2020-07-28T01:57:57Z")
I dunno, this article suggests otherwise. > **[Statistics, Exoplanets, and the Search for Earthlike Planets](https://statisticsbyjim.com/fun/statistics-exoplanets-search-for-earthlike-planets/)** > > A statistical look at the discovered exoplanets to see how Earth fits in. The probability of Earthlike planets depends on the distribution of exoplanets. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [July 28, 2020, 3:13am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/33 "2020-07-28T03:13:18Z")
In about 45 minutes. Grab your towel and let’s head to the pub for 3 pints and a bag of peanuts. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2020, 3:23am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/34 "2020-07-28T03:23:40Z")
> [@Blue\_Blistering\_Barnacle](#): > > I dunno, this article suggests Well, yes, but I was addressing your point about viewing angle and areas of the sky examined. And my point about the handful of dice still stands. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2020, 3:28am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/35 "2020-07-28T03:28:44Z")
Try these articles > **[There's Basically 'No Chance' for Earth-Like Planets to Form an Atmosphere...](https://www.livescience.com/65318-young-suns-shredding-earth-like-atmospheres.html)** > > The odds of an atmosphere forming around an Earth-like exoplanet are even slimmer than previously thought, a new study suggests. > **[Sorry, 'Earth 2.0' Fans, There's No Such Thing As An Earth-Like Exoplanet](https://www.forbes.com/sites/startswithabang/2020/04/22/sorry-earth-2-0-fans-theres-no-such-thing-as-an-earth-like-exoplanet/#6056ee751989)** > > The dream of an 'Earth-like' planet showcases our astrobiological ignorance. ---
**Author:** ![Pavelb1](https://avatars.discourse-cdn.com/v4/letter/p/439d5e/32.png) [@Pavelb1](https://boards.straightdope.com/u/Pavelb1)\ **Post date:** [July 28, 2020, 5:25am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/36 "2020-07-28T05:25:20Z")
Barring something nuts like “The moon is actually a base for aliens and our leaders know all about it and thats why they shut off cameras on the ISS whenever a ship appears”\*… I think we have to accept that they have FTL travel. Hey…IFFFFFFF the craft we see in those ‘fighter craft follow UFOs clips’ ARE aliens. Well hell, they already exhibit impossible inertia-defying properties. Doesn’t mean they can go FTL of course, but if they’re doing one impossible thing already??? Yes i know its a stretch. - What??? No one else owned The Big Book of Conspiracies?? ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 28, 2020, 6:50am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/37 "2020-07-28T06:50:03Z")
> [@Pavelb1](#): > > I think we have to accept that they have FTL travel. Ummm…why? I know you’re the OP but isn’t the topic of the thread theories why we don’t see aliens here on Earth? A limit of the speed on travel would explain it. Or is your topic more along the lines of “Assume aliens visit Earth on a regular basis. Now come up with a theory to explain why we don’t see any evidence of aliens visiting Earth on a regular basis.” ---
**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:** [July 28, 2020, 8:05am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/38 "2020-07-28T08:05:37Z")
The Forbes article is saying that there are probably more planets with life than we expect if we look only for earthlike ones, so that doesn’t quite support your argument. The other one doesn’t quite explain how we managed to make it. Do you have a cite saying that current techniques can find all sizes of planets at all distances from their stars? ---
**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:** [July 28, 2020, 8:07am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/39 "2020-07-28T08:07:46Z")
> [@Pavelb1](#): > > What??? No one else owned The Big Book of Conspiracies?? You’re not reading about the really interesting conspiracies. A woman in my critique group thinks that UFOs are piloted by fallen angel lizard beings. Who came down here and are responsible for the theory of evolution. She is also a flat-earther. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [July 28, 2020, 9:10am UTC](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388/40 "2020-07-28T09:10:06Z")
> [@Voyager](#): > > Do you have a cite saying that current techniques can find all sizes of planets at all distances from their stars? No. Do you have a cite where I made that claim? [Previous page](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388.md?page=1) [Next page](https://boards.straightdope.com/t/my-theory-on-alien-life-and-our-planets-place-in-the-galaxy/916388.md?page=3)