# If we found conclusive proof of an advanced alien civilization, say \<10 light years away, could we communicate with them? **URL:** \ **Category:** Factual Questions\ **Created:** [April 1, 2026, 7:16pm UTC](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940 "2026-04-01T19:16:29Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 5, 2026, 10:12pm UTC](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940/21 "2026-04-05T22:12:00Z")
> [@eburacum45](#): > > Not really true; an ocean planet with a deep high-pressure ice mantle could have an oxygen-rich atmosphere simply by photolysis; certain types of water-rich, tidally-locked worlds could have oxygen-rich atmospheres for a similar reason. It’s my understanding that, while these processes can produce an atmosphere of mostly oxygen, it’d still be a much thinner atmosphere than ours, so a thick oxygen atmosphere would still catch our interest. But it does illustrate a good point, in that that process wasn’t hypothesized until relatively recently, and so before then, if we’d found such a world, we’d have assumed life. Now, it might be reasonable for Star Trek to have scanners that can detect “life signs”. The Federation has seen thousands of worlds up close, both life-bearing and otherwise. With that kind of data, you can start doing some serious science. We, meanwhile, have only sent probes to the surfaces of four worlds, and only one of those (to the best of our knowledge) has life, so we don’t really have any idea what the true, reliable signs of life 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:** [April 5, 2026, 10:22pm UTC](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940/22 "2026-04-05T22:22:19Z")
> [@Chronos](#): > > It’s my understanding that, while these processes can produce an atmosphere of mostly oxygen, it’d still be a much thinner atmosphere than ours, so a thick oxygen atmosphere would still catch our interest. Maybe not; one recent paper talks about 2000 bar of abiotic oxygen. But as I said this would look very different to Earth. > **[Extreme Water Loss and Abiotic O2 Buildup on Planets Throughout the Habitable...](https://pmc.ncbi.nlm.nih.gov/articles/PMC4323125/)** > > We show that terrestrial planets in the habitable zones of M dwarfs older than ∼1 Gyr could have been in runaway greenhouses for several hundred million years following their formation due to the star's extended pre-main sequence phase, provided ... ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [April 6, 2026, 8:05am UTC](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940/23 "2026-04-06T08:05:24Z")
> [@eburacum45](#): > > Not really true; an ocean planet with a deep high-pressure ice mantle could have an oxygen-rich atmosphere simply by photolysis; certain types of water-rich, tidally-locked worlds could have oxygen-rich atmospheres for a similar reason. Known to scientists as a “class M” planet, of course. ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [April 9, 2026, 9:31pm UTC](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940/24 "2026-04-09T21:31:13Z")
> [@HeyHomie](#): > > OK, you know how in Sci-Fi, the crew of The Spacecraft “scan for signs of life” when approaching a new planet? Is this a thing that can be done a) at all and b) from Earth? [According to XKCD](https://what-if.xkcd.com/47/) aliens could detect our algae, so we could detect theirs? [Previous page](https://boards.straightdope.com/t/if-we-found-conclusive-proof-of-an-advanced-alien-civilization-say-10-light-years-away-could-we-communicate-with-them/1028940.md?page=1)