Slashdot Mirror
Does Active SETI Put Earth in Danger?
Ponca City, We Love You writes "There is an interesting story in Seed Magazine on active SETI — sending out signals to try to contact other civilizations in nearby star systems. Alexander Zaitsev, Chief Scientist at the Russian Academy of Sciences' Institute of Radio Engineering and Electronics, has access to one of the most powerful radio transmitters on Earth and has already sent several messages to nearby, sun-like stars. But some scientists think that Zaitsev is not only acting out of turn by independently speaking for everyone on the entire planet but believe there are possible dangers we may unleash by announcing ourselves to the unknown darkness. This ground has been explored before in countless works of science fiction most notably "The Killing Star," a 1995 novel that paints a frightening picture of interstellar civilizations exterminating their neighbors with relativistic bombardments, not from malice, but simply because it is the most logical action."
Saberhagen's Berserker series? Bear's The Forge of God and Anvil of Stars? What is this The Killing Star that you speak of?
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
Radio and TV signals will not be propagated very far into space because they aren't directed there. Sending signals to other stars, OTOH, would direct the transmitted power to outer space, not to the earth surface.
Or better yet, do some research before you post. The combined total invested in SETI is a very small fraction of "...billions in [...] cold hard cash..."
The amount spent is in the millions and nowhere near the billion level. One billion man hours equals about 114 years of work by 1,000 researchers. How many scientists are working on SETI? A thousand? Probably far fewer.
You are very wrong in your estimate of the financial and manhour investment in SETI. I'm not an advocate of SETI research (it seems like a waste to me, as the chance of success is pitifully low), but let's not exaggerate out of ignorance or malice.
Ah, there's another assumption, that a galactic civilization would use radio waves. Radio is pretty useless for communication on a galactic scale. It takes too long for a message to get across the galaxy, and the inverse square law means that any non-directional radio would need one hell of a powerful transmitter.
Give me Classic Slashdot or give me death!
The Worst Guy In History invaded Poland. We went to war to stop him. We won. HURRAH! Then we went home and left Poland to the tender mercies of The Second Worst Guy In History. I'm not sure they'll forgive us all that much...
Real Daleks don't climb stairs - they level the building.
Time scales are a problem, but so is power. Although we have been broadcasting radio and TV signals from earth for a while, the signal power at any meaningful distance scale is really, really small. From wikipedia (in turn summarized from the SETI FAQ): "SETI estimates, for instance, that with a radio telescope as sensitive as the Arecibo Observatory, Earth's television and radio broadcasts would only be detectable at distances up to 0.3 light years. Clearly detecting an Earth type civilization at great distances is difficult." Keep in mind that 0.3 light years isn't even out of the Oort cloud of our own solar system. For this reason, the idea that all of our embarrassing TV and radio shows will be our first ambassadors to the stars is a little far fetched. In the movie Contact, Sagan uses this for good dramatic effect to imply that the 1936 games in Berlin would be the first meaningful signal detected by aliens from earth. Although the guy in the article doesn't eliminate the time scale problem, he is at least directing his signals at targets using rather high signal power. If anything is out there to here is, it will be via a mechanism like this.
i\hbar\dot{\psi}=\hat{H}\psi