How Aliens Could Map the Earth

If an extra-terrestrial civilisation saw the Earth, what technosignatures could they pick up? What could they learn about life on our planet and human civilisation in particular? I'm discussing that with Dr Michael Garrett who is the Director of Jodrell Bank Centre for Astrophysics.

👉 Simulation of the Earth’s radio-leakage from mobile towers as seen from selected nearby stellar systems:

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00:00 Intro
02:11 Biosignatures in modern Astronomy
06:46 Technosignatures VS biosignatures
13:07 Loudest technosignatures of Earth
18:27 Earth from the perspective of aliens
32:31 Satellite constellations
38:00 Going into wires
42:49 Leaked transmissions
46:09 Becoming an alien hunter

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Creative Commons Attribution 4.0 International (CC BY 4.0)

You are free to use my work for any purpose you like, just mention me as the source and link back to this video.

[WillDa]

the idea of this many satellites parked in low earth orbit really scares me. like sure i like being able to have Fraser's incredible content on one screen and work on the other, i like being able to look at pretty pictures of the cosmos but i also like to go out at night and look at the stars.. yknow.. with my human eyes

[jimcabezola]

Mahalo for this interview, Fraser. As I watched it...I was looking at another screen tracking the Axiom 2 countdown. It's folks like Dr. Garrett and YOU who make sense of all these wonders, and I certainly thank you two among others who bring us the science! Aloha.

[ChemEDan]

NASA: Can you detect life on Earth?
Voyager: **carefully analyses situation...**
Voyager: Yes, and great Scott, it appears to be communicating with me!

[ricksspeedshop]

Wow! One of the many, most interesting interviews you conducted! Really thought provoking. Thank you, sir!

[Yezpahr]

24:24 "Crazy hoomans, don't litter please! And we're keeping that gold plate if you just gonna toss it out there anyway..."

[Swede__DJT]

Greetings from Sweden!

This is one of your best interviews.

Keep this stuff coming plz!🎉

[michaelrice]

Didn't think I'd see a celtic Jersey in a fraser cain interview. Didn't think this channel could get any better

[derongranville]

Fraser - thank for posting the link to the original paper!

[alphanaut]

I don't think we are going to give up radio communication, but the strength of the signals has dropped significantly. We're not broadcasting as many MegaWatt Radio Stations- they've been replaced with billions of 3 Watt signals that are not detectable at any kind of distance. The chatter might be going up, but the signal strength is nothing.

[JamesCairney]

I like the Celtic football top, good interview as well

[jensphiliphohmann]

46:20 f: _...a career of being an alien hunter..._
An alien, learning this: "Damn, these guys want to prey on us!"

[dmrr]

If you had asked me a couple years ago, I would think fiber optics would decimate satellite communications. But if we wind up in a hot war in the next few years, undersea cables will probably be one of the first targets.

[winstonsmith]

Dr Seth Shostak answers your questions about SETI (2005)

Q: What is the maximum distance at which SETI can detect signals which are not deliberately beamed at us, such as normal radio telecommunications traffic?

A: Our best SETI experiments to date could detect Earth-like “leakage” signals at no more than 1 light-year’s distance. So not too far.

Aliens can't hear us, says astronomer [so, we can't hear them]
Fainter broadcasting signals and digital switchover mean Earth will soon be undetectable to extraterrestrials (2010)

[peterkordas]

I am about to watch this program, so there may be answer there to my question:

We often talk about how noisy the earth has been, basically since Marconi switched on his transmitter.

However, from what I understand, not all frequencies make it out past the ionosphere, many just bounce off it a few times before dissipating.

Ham radio enthusiasts pay particular attention to the state of the ionosphere if they hope to catch long distance transmissions, knowing there are daily variables to it's"bouncability".

So, which radio waves would actually make it out past the ionosphere, and how does that alter our perception of how detectable earth could be at interstellar distances?

And, while others are doing their sums, what would be the strength of a, lets say 100KW signal, by the time it travels 10 light years? or, as some feel, the earth may be detectable 60, 70 or more light years away?

Questions, I have... answers? not so much

[seditt]

Will the Vera Rubin( sp?) Telescope perform spectroscopy as well? I would love to see a survey telescope containing such a thing as AI could make short work of looking for narrow band signals. I personally am convinced Aliens would abandon radio rather quickly as we see a rapid move up the EM spectrum as its the natural evolution of such communications due to bandwidth constraints. Lasers provide a far more efficient and direct contact over long distances especially if a civilization is advanced enough to produce efficient lasers.

[thebigerns]

Besides how visible our signals are, I wonder if it's also important how interesting they are. Do we really notice the smoke signals of isolated human tribes with our satellites? 🤔

[FredBennett-qe]

Can we "see" radio waves like we can "see" infrared? That would be cool.

[rightcheer]

I was thinking that we could take all the space debris around Earth and use solar magnets to generate a series of concentric circles to let aliens know that there’s a civilization here, and where to aim.

WWII British got a lot from signals analysis even when they didn’t know what was being said. I bet there is a book or paper somewhere that has been declassified that would provide a lot of ideas.

[VIBrunazo]

Didn't have time to finish watching the whole thing yet. Did they talk about how does the inverse square law reducing radio signal strength from Earth affect how visible we are? Would a civilization with comparable technology to ours still be able to notice our radio transmissions despite that?