Stephen Hawking says civilizations on other planets in unlikely for at least...

S

Scott

New member
...several hundred light years... ? because we have picked up no radio signals from these distances. Is there not a possibility of a civilization without radios? And what are the possibilities of there being uncivilized beings on other planets close to us?
Well, that's interesting. There's a vid on youtube where Hawking says that. I mistook him for a genius!
 
Incorrect statement. We've only been listening for the last 50 or so years which means we are limited to a 50 lightyear radius - not several hundred light years. If it were several hundred then we must have had radio telescopes pointed at the sky in the 1300's.
 
If I can remember correctly the SETI project (ie the people looking for "intelligent" signals from space) they are overing the entire spectrum that is usable for communications (ie not light and not sound but somewhere in between). This has been going on for at least 25 years (at least part of the spectrum has been monitored for about 50 years). If there was a species that wants to do communication using a non LOS (line of sight) method they will need to use a signal in this spectrum. Keep in mind that the Earth only sent their first powerful enough signal just before WWII (it was a message of Hitler opening the Olympic games).

If I can remember correctly form my astronomy class, there is roughly a 0.00000000001% chance that any given system will have intelligent life develop on it. On average any given galaxy over the span of a couple billion years will have about 100 intelligent species. So that means there were about 100 intelligent species in the Milky Way galaxy (us included). Some of these species will have already gone extinct and some have not yet developed. I would hazard to guess that only a handful of intelligent species exist currently in the galaxy and they are not within communication distance (let alone travelling distance) to the Earth.
 
Actually the limit others put does not apply in this case.

They are thinking of the limit that we could be detected.

If a civilization 100 light years away have been generating radio signals for 100 years, then we could detect them and so on.

Now, the assumption is that any advance civilization would generate radio signals if only from the production of electricity.

Is this assumption valid? Who knows, but it seems like a good one. Any civilized culture would have to generate some sort of radio noise even if was not reruns of Spongebob. . .
 
Actually the limit others put does not apply in this case.

They are thinking of the limit that we could be detected.

If a civilization 100 light years away have been generating radio signals for 100 years, then we could detect them and so on.

Now, the assumption is that any advance civilization would generate radio signals if only from the production of electricity.

Is this assumption valid? Who knows, but it seems like a good one. Any civilized culture would have to generate some sort of radio noise even if was not reruns of Spongebob. . .
 
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