SETI searches for alien life in over 1,000 galaxies using unexplored radio frequencies

[Admin]

New findings could elevate SETI into an extragalactic search for life beyond Earth.

SETI searches for alien life in over 1,000 galaxies using unexplored radio frequencies : Read more

 

[Jan Steinman]

This article refers to detecting a "maximum detectable power".

Perhaps I misunderstand, but I think what was really specified was a "minimum detectable power."

All transmitters of more than "10^23 watts to 10^26 watts" would be as detectable as one putting out a mere 9.999 x 10^22 watts, no? So, a transmitter with a higher power output would be equally detectable as one putting out the "minimum" detectable power.

For comparison, a large FM radio station — which falls within the range of frequencies monitored — emits 5 x 10^4 watts, and there may be some 10,000 of these in the world, making the total power about 10^8 watts. (The most powerful radio transmitter on Earth puts out a mere 3 x 10^6, and that is outside of the frequency range of this study.)

 

[AboveAndBeyond]

The frequency is one thing but no mention was made of the bandwidth resolution they had. Artificial signals are likely to have their power concentrated in a small frequency interval (compared to natural sources), so it's not power but power per Hz that matters.

 

[Jan Steinman]

Artificial signals are likely to have their power concentrated in a small frequency interval (compared to natural sources)…

The opposite trend seems to be happening for humans. We are increasingly using spread-spectrum techniques. Plus, we're layering advanced encoding and cryptography on top of that. The rapidly approaching switch to quantum encryption may further disguise us.

Some think this may be a limiting factor in the Drake equation, that advanced civilizations may "go invisible" to less-advanced civilizations as their technology improves.

I think it was Claude Shannon who said something like, "Optimally encoded information is indistinguishable from noise, unless you have the decoding key."

Perhaps the "noise" of the Universe is really just advanced civilizations chatting to each other, but we lack the decoding key?