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Anonymous Coward writes:
https://www.businessinsider.com/alien-civilizations-may-have-already-colonized-galaxy-study-2019-8
The Milky Way could be teeming with interstellar alien civilizations — we just don't know about it because they haven't paid us a visit in 10 million years.
A study published last month in The Astronomical Journal[$] posits that intelligent extraterrestrial life could be taking its time to explore the galaxy, harnessing star systems' movement to make star-hopping easier.
The work is a new response to a question known as the Fermi paradox, which asks why we haven't detected signs of extraterrestrial intelligence.
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Fermi Paradox Paper: Aliens Could Take Their Time Settling the Galaxy
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(Score: 1, Insightful) by Anonymous Coward on Tuesday September 10 2019, @10:46AM (6 children)
Not sure who your talking about "him" but I'm assuming to me? I'm not sure what Carl Sagan would think about. Anyway, Fermi Paradox is assumptions on assumptions, like this guy,
https://www.theguardian.com/lifeandstyle/2019/sep/09/all-you-need-is-maths-the-man-using-equations-to-find-love [theguardian.com]
and then you may notice, that communication is TWO way street. Fermi Paradox *assumes* that somehow *we* will see aliens and they will magically notice us too because we managed to move electrons and produce our own "invisible ether waves". But how is it any different than assuming aliens should notice or care about our smoke signals that preceded radio waves? It's as humble as stating "we know all physics and rest is just refinement".
Fermi Paradox was created by one arrogant ant on some hill somewhere!
(Score: 2) by c0lo on Tuesday September 10 2019, @11:06AM (1 child)
Sorry for being ambiguous, I was talking about Fermi, wondering if he was serious with his paradox or just teasing.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Bot on Tuesday September 10 2019, @01:54PM
This seems a good context to remind us of
The Fermi paradox paradox:
"I just made the atomic bomb. Why don't aliens speak to us?"
Account abandoned.
(Score: 3, Insightful) by takyon on Tuesday September 10 2019, @11:18AM (3 children)
Two way communication is not needed for you to find out that an alien civilization exists. You could look for megastructures. You could look for exoplanets with biospheres, then focus on those planets to find further evidence of intelligent life.
Even finding evidence of a now-extinct civilization would be more satisfying than knowing nothing.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Interesting) by Immerman on Tuesday September 10 2019, @01:29PM (2 children)
And at present we've detected one just-maybe megastructure (or unusual cloud of large debris), have detected a (large) handful of nearby planets whose orbital planes happen to be very near to our line of sight, and have the technology to get a very rough glimpse at the atmospheres of some of the very closest of those.
There's not really much reason to expect us to detect life that way. Not any time soon anyway, not unless the galaxy is absolutely teeming with it.
The usual presumption with the Fermi Paradox is that the aliens are communicating across interstellar distances, and we know all the physics necessary to detect those signals. Or alternately, that at least one species is in the process of colonizing the galaxy, and likely has been for millions if not billions of years - in which case it's odd that they're not already here in person.
(Score: 4, Interesting) by takyon on Tuesday September 10 2019, @03:05PM (1 child)
We went from a handful of known exoplanets to thousands in a short amount of time, but we are still in the dark ages of exoplanet detection, spectroscopy, and direct imaging. We will get better at it. We could use many gigantic space telescopes to get better results.
Megastructures are fun to look for, not necessarily the way we will confirm life. I brought them up because you don't need to find evidence of radio communications, just an optical detection. Maybe a dead civilization transmitting no signals could leave behind detectable megastructures.
There ought to be a larger number of exoplanets with biospheres than ones with intelligent life forms. So we need to detect smaller exoplanets, more of them, especially ones further away. We can look at atmospheric composition, or even directly image continents, vegetation, etc. on the surface. We might need telescopes with kilometer+ apertures and huge light collecting capability, along with starshades. A gravitational lens telescope [airspacemag.com] could also work (see Mars image and caption) but it will be hard to exploit that effect the way we want to at 550+ AU away. The "terrascope" [soylentnews.org] looks more promising in the short term.
Anyway, if you can find an exoplanet that has evidence of microbial or plant life, you have a good candidate for intense follow-up studies to look for signs of civilization. But even if we don't find intelligent life this way, we can work on the easier problem of finding biospheres (less terms in the Drake equation). These planets could become targets for our own interstellar expansion.
http://curious.astro.cornell.edu/people-and-astronomy/131-observational-astronomy/seti-and-extraterrestrial-life/seti/796-why-does-the-seti-project-search-for-radio-signals-intermediate [cornell.edu]
I think it's dubious that we can detect any interesting radio signals. Interference and noise would make a broadcast from Alpha Centauri hard to detect, much less anywhere further. And we can rule out the idea of detecting powerful, highly directional signals since that requires luck and good timing.
So the galaxy could be filled with alien AM, FM, etc. radio broadcasts and we would not know about it. It could be much easier to find a planet with vegetation on it and just continually improve our optical resolution until we can resolve any skyscrapers, electric lighting, etc.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by Immerman on Tuesday September 10 2019, @03:32PM
Quite so. It may well be that life is far easier to detect across interstellar distances than civilizations, At least life that re-engineers planets the way it did here - would we recognize the environmental signature of methane-breathing life? But as I recall even an ideal future telescope using the sun as a gravitational lens would have trouble resolving individual building on an planet around the closest star, so we'll likely be limited to detecting seasonal changes, and large-scale flocking behavior and have to infer the rest. Easily good enough for two-way communication if they knew we were here, but otherwise difficult to conclusively identify a technological civilization unless they were similarly big fans of artificial lighting at night.
At present though our technology is only good enough to barely dip our toes in that ocean.