Can we hear radio signals from earth reflected from distant planets?
Can we hear the first radio transmissions from earth?
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answers:
WHANKING-WILLY say: No. The inverse square law is logarithmic, meaning that the intensity is inversely proportional to the square of the distance from the source of that physical quantity. That is, the signal will be so weak as to be lost in the background noise of the cosmic radiation. Sorry, but that is physics.
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MARK say: You cannot hear radio signals.
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Ronald 7 say: Yes Radar is comprised of Radio beams and a great way of finding distance
Radar has been bounced off the Moon, Venus and Mercury then back to Earth for instance
The trouble is if it is not concentrated and amplified there and back, it loses its strength to the inverse square
Distant planets would need a transmitting dish the size of the Solar System, Oort cloud and all to be effective
Arricebo and Seti are doing their best but distance is the biggest barrier
Aliens would really have to pinpoint Earth in the vastness of space
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William say: This question reminds me of an experience I had at White Sands in the 70s. The sky was clear and we heard a constant booming almost like low rumbling thunder and was informed by Rangers that it was radio waves bouncing off the desert sands. These weren't reflected from planets but rather Earth's atmosphere or at most the Moon (Nyx has cited similar instances).
Strange experience and explanation, which I still do not know was true or not. This was 1978, prior to the nearby Jansky VLBA (I think), begun in 1975 and which wasn't inaugurated until 1980.
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nineteenthly say: No, they're undetectable from less than a light year away.
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PhotonX say: For Solar System objects, yes. That's what radar is, bouncing radio waves off of objects, so the discipline is called radar astronomy. https://en.wikipedia.org/wiki/Radar_astr...
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Carl Sagan's novel Contact is based on a similar idea, though, with our early television signals being intentionally returned to Earth from a civilization in the Vega system.
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CarolOklaNola say: Yes, but they have to be fairly close to Eat. That is how the surface e of Venus was mapped in the 1950s and 1960s
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Nyx say: Earth-Moon-Earth radio communications have been done since the mid '40's. Amatuer radio operators (hams) do moonbounce stuff too.
http://www.ok2kkw.com/eme1960/eme1960eng...
https://www.qsl.net/sterling/Activities/...
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Raymond say: Radar echos can be "heard" if they are beamed to other bodies within the Solar system (for example, Mercury).
AM (or even FM) radio transmissions did escape to space, but they were not beamed, so the signal would have quickly spread out, leaving a very tiny flux to bounce off anything. Aome people worked hard to hear unbeamed radio signals bounced from the Moon.
Distant planets? no.
The first commercial radio broadcast (say around 1928) would need a planet located 45 light-years away for that signal to be heard here, today.
At that distance, the signal's flux would be too weak to be detected directly, never mind its reflection off a planetary surface.
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Starrysky say: Yes. Radar beams from Arecibo dish observatory Puerto Rico are bounced off Venus and asteroids.
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