Detection of Earth-like Civilizations in Space Now Possible

Mr. McGibby writes "Astronomers have come up with an improved method of looking for extraterrestrial life with an Earth-like civilization. Theorist Avi Loeb proposes to use instruments like the Low Frequency Demonstrator (LFD) of the Mileura Wide-Field Array (MWA), an Australian facility for radio astronomy currently under construction. The array could (theoretically) detect civilizations broadcasting in the same frequencies as our own society. From the article: 'Loeb and Zaldarriaga calculate that by staring at the sky for a month, the MWA-LFD could detect Earth-like radio signals from a distance of up to 30 light-years, which would encompass approximately 1,000 stars. More powerful broadcasts could be detected to even greater distances. Future observatories like the Square Kilometer Array could detect Earth-like broadcasts from 10 times farther away, which would encompass 100 million stars. ' The original paper describes the details."

Comments

Re:any physicists out there?

[inviolet]

Isn't there something to do with the spin of an electron, which when you reverse the spin, immediately reverses the spin of some other electron, with no delay? Couldn't you reverse the spin of a bunch of electrons on earth, and have their counterparts match the reversal, 30 light years away. It could be used for exchanging information at faster than light speeds.

You are thinking of quantum entanglement, aka "spooky action at a distance".

It cannot be used to transmit information. Think of it this way:

1. You take two slips of paper, one black and one white, and put them in envelopes.
2. You randomly select an envelope and mail it to your brother in Poughkeepsie. You keep the other envelope for yourself.
3. While the envelopes are in transit, nobody has yet observed their contents (i.e. their spins). Yet you know that their contents (their spins) must be opposite because they are an entangled pair.
4. The envelope travels to Poughkeepsie at the speed of light, or significantly slower in the case of the US Postal Service.
5. Your brother receives and opens his envelope. He observes that his slip of paper is black. The uncertainty collapses: he now instantly knows that your slip of paper is white.

Notice that you cannot send actual information by this route. The uncertainty of "which slip of paper is in my envelope?" collapses instantaneously, but it collapses into a random choice. Neither of you could know in advance which color you would find in your envelope.

This illustration changes slightly when executed at the quantum level: while the envelopes were in transit, both slips of paper were actually grey... though some might insist that they were both all possible colors, until they were finally observed.

Re:Knowing Your Neighbours

[silentounce]

This argument has come up several times. If you RTFA then you will see this: "On Earth, military radars are the most powerful broadcast sources, followed by television and FM radio. If similar broadcast sources exist on other planets, facilities like MWA-LFD might detect them."

TV and communication media are not the only sources of radio waves. It would stand to reason that most civilizations that develop flight will eventually develop radar. Radar is very simple and reliable. Yeah, I know that there are stealth technologies, but commercial jetliners aren't using them. We'll probably be using radar for a very long time. Plus, radio is our current means of communicating with our spacecraft(isn't it? I may be wrong). If the society is space faring, and they have a well-developed space program, that may be a large source of radio waves that won't even have to escape an atmosphere.