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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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The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Oh, that sound of male ego. You travel halfway across the galaxy and
it's still the same song.
-- Eve McHuron, "Mudd's Women", stardate 1330.1
(Score: 5, Informative) by c0lo on Tuesday September 10 2019, @08:07AM (8 children)
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** optical, but I'm to lazy to search for radiotelescope dishes
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Tuesday September 10 2019, @08:33AM (1 child)
at this point i'm pretty sure arik is trolling, but please be aware that there is at least me who finds your replies informative.
(Score: 2) by Arik on Tuesday September 10 2019, @09:14AM
If I understand the subject better than anyone within 100 miles, and I know damn well I don't understand it at all, what am I to do?
I'm not above posting something that's clearly wrong and inviting anyone that has the ability to shred me. But when I'm doing that I usually write it out that way explicitly.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by Arik on Tuesday September 10 2019, @09:11AM (4 children)
I'm not sure your numbers are right; to the contrary they seem hard to accept. I remember in the freaking 80s being told by grey-haired professors in the field that if any civilization like our own existed at the correct time/space distance to be detected we could pick it up. No, we weren't scanning every possible angle at once, we were scanning a fairly small portion intensively and the rest got much less coverage, but we could pick up the signals not just in this galaxy but in several neighboring ones. And we were expecting to pick up an alien sitcom any day now. And we've been steadily expanding our coverage, surely there aren't many angles left unmonitored today?
So I don't now. Either my understanding of the tech back then was dramatically wrong, or we haven't expanded our abilities at anything remotely like we expected, or some other shit, or maybe as I think currently we are at a point where we could probably detect and decode a few extraterrestrial nee extrasolar transmissions were our basic assumptions about the universe correct, yet we do not detect those signals.
Or I guess you could go full infowars and claim we've got the signals they just aren't released.
Whatever. I'm not claiming I know what's going on I'm just pointing out why I doubt anyone else knows either.
If laughter is the best medicine, who are the best doctors?
(Score: 4, Interesting) by Runaway1956 on Tuesday September 10 2019, @10:15AM (2 children)
I strongly suspect those gray haired old men were full of something other than science. c0lo's post about the relative power of random noise generated by Jupiter, and the earth's total radio transmissions pretty much covers the matter. That amounts to a Ham radio operator trying to pull in the faintest of signals from the other side of the world on skip, while his neighbor cranks up the filthiest, noisiest, least filtered and most poorly tuned generator in the world. The generator is unintentionally broadcasting 100 to 1000 times more energy across the radio spectrum, than that distant Ham operator has at his disposal.
Those who were born before the ubiquity of resistor spark plugs remember how hard it was to pull in nearby radio stations, let alone distant stations. https://www.ngk.com/learning-center/article/804/what-is-a-resistor-spark-plug [ngk.com] Yesterday's rural radio nerd could sometimes tell you who was driving past his home, just by listening to the static generated by the vehicle.
(Score: 2) by Rupert Pupnick on Tuesday September 10 2019, @05:06PM (1 child)
Hair dryers were the absolutely worst sources of RFI back in days of analog transmission through free space.
(Score: 1, Insightful) by Anonymous Coward on Wednesday September 11 2019, @03:34AM
Nope. Arc welder. Ask how my neighbor knows. ;)
(Score: 3, Insightful) by c0lo on Tuesday September 10 2019, @11:00AM
I would start here and determine the maximum distance at which we could detect something emitted with a reasonable power (keeping into account the entire Earth civilization radiated EM power is 0.1 GW).
The most modern radio-telescope [wikipedia.org] can search (alone) to a distance of 28 ly.
The thing get funny pretty quickly if you start taking into account things like the wavefront form - TV emission make sense to be emitted in a plane, the "vertical" lobe of an antenna would be just losses for TV. So, imagine a plane on strong emission tangent to a planet that's rotating. How long that plane will sweep an observation point at some light-years away? Will the blip be long enough to be considered "encoded TV signal" by the receiver? If you assume many such "emission planes" from many TV stations on that rotating planet, will the signal received at distance look like "encoded TV" or just noise? SETI [wikipedia.org]
Oops - 1 hour of continuous encoded transmission? Only if they deliberately maintain the direction of emission for that time. As they don't know we are here, it will be an almost literal stab in the dark [wikipedia.org].
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Muad'Dave on Wednesday September 11 2019, @12:44PM
Most of your analysis is spot-on, but I have to disagree with the way you used this factoid.
That's the power emitted by planet Earth itself, not Earth's inhabitants. Our radio signature is significantly stronger than 0.1 GW = 100MW - in fact, the Arecibo transmitter [wikipedia.org] alone outshines the Earth's RF emissions by 5 orders of magnitude on one frequency, at least in a very tight beam. Arecibo has "... four radar transmitters, with effective isotropic radiated powers of 20 TW (continuous) at 2380 MHz, 2.5 TW (pulse peak) at 430 MHz, 300 MW at 47 MHz, and 6 MW at 8 MHz."
If you discount that one as being too narrow, then add up all of the omnidirectional radar and shortwave transmitters. Many of the radar transmitters mentioned in table 2 of this doc [doc.gov] have EIRP's over a GW. Even though they're low duty cycle pulsed emissions, they'd still be detectable at very long distances.
Also, Earth's emissions are mostly in the HF band (as are Jupiter's). Seeing any emissions past UHF would indicate some other process, possibly intelligent, was at play.