Posted on 04/11/2006 7:31:19 PM PDT by KevinDavis
The first optical telescope dedicated to the hunt for alien signals has opened.
For almost 50 years, since SETI (Search for Extraterrestrial Intelligence) projects began in earnest, people have concentrated on detecting radio signals, says Paul Horowitz, an astronomer at Harvard University in Massachusetts, US. But recently, researchers have come to think alien civilisations could also plausibly use laser light to communicate.
Horowitz led the construction of the Planetary Society's Optical SETI (OSETI) telescope at Harvard's Oak Ridge Observatory. Once running, OSETI's processors will carry out a trillion measurements per second, in a year-round survey of the sky. It will be able to pick out flashes of light that are only a billionth of a second long.
And because it does not need to take high-resolution images, it is much cheaper than other professional telescopes, costing just $50,000 to build. "It's really a light bucket," says Horowitz. "It won't take pretty pictures."
The OSETI telescope has a mirror 1.8 metres (72 inches) in diameter, and custom-built photomultiplier tubes and processing chips.
Unidirectional signal
OSETI opens on Tuesday April 11 to begin its search. "It may be a longshot," says Horowitz. "But this has such important implications, someone should be doing it."
Horowitz believes that radio astronomy searches still play an important role in the search for alien life. Alien civilizations would actually find radio better for long-range communication because radio waves are not blocked by dust within galaxies, he says.
But optical laser pulses could also filter through many regions of the sky, says Horowitz. And since laser light is unidirectional, it will be easier to pinpoint the location from which a signal originates.
Astronomer, Luc Arnold, at the Observatory of Haute-Provence in France, has researched how space-based telescopes could be used to detect laser pulses produced by alien civilisations.
He is excited by OSETI's fast processing power, which makes a ground-based search possible. "Radio SETI should not be the only method considered," says Arnold. "We must remember that ET could be quite imaginative."
OK Class... for your final question. If the radio signal left alpha centaurs 150,000 years ago and a Laser signal went out fifty years later... how many lightyears till the Laser passes the Radio signal???
Show your work.
Extra Points if you answer the question without a calculator
"We must remember that ET could be quite imaginative."
Am I the only one who finds this statement hillarious? Physicists today seem clueless about history. They thought they knew everything there is to know a hundred years ago and they still think so.
We may not recognize or even be capable of recognizing an alien signal.
Interesting. Lemme know if you see anything else on this.
That's one of my big gripes about the scientific community.What is unassailable now that schoolchildren will snicker at in another hundred years?
"But I am not really willing to accept your premise, because it may well be that the means of communications they have are of a kind that we do not know how to receive, and that they would not have the means of communicating with sufficiently powerful radio or optical signals. That is something which, technologically, is too difficult for them but they would have some other means we would not recognize." -- Thomas J. Gold (Communication with Extraterrestial Intelligence)
--We may not recognize or even be capable of recognizing an alien signal.
Yeah, that's what I think. I think it's completely possible that within a half century or so we'll have technology that will make speed of light communications obsolete. But of course the physicists poo-poo this and know everthing just like they thought they did around the turn of the last century.
that's my public schooling showing, i thought light was just a tad faster than radio.
Our progress in information theory has been in response to our communication devices. It started with Morse and the desire to increase the amount of information that could be carried on a wire. Some of the theory is surprising, and came into its own as recently as WW II. It would be difficult to devise theory for devices that have not been imagined.
Any space faring race will need a means of communication that's faster than light. Even within our solar system radio communication becomes problematic at distances much beyond the moon.
It is relatively easy to make a signal appear different from a natural signal. We aren't listening for "hello, how are you?" We are looking for anything that stands out distinctly from the natural signals.
I would imagine aliens would seek communication methods that would travel faster than light, but what would it be...
--It is relatively easy to make a signal appear different from a natural signal. We aren't listening for "hello, how are you?" We are looking for anything that stands out distinctly from the natural signals.
Yes, but I'm not sure how that addresses my point about the assumptions made about the technology used for it. For all we know we are using a very temporary technology when the real action is elsewhere.
It will be fifty years behind the radio signal. It will not pass it.
Never.
Listening for optical or radio signals may be as futile as watching for smoke-signals. Advanced alien races, and the probabilities of a large universe suggest they are out there, may use a form of communication which is even now blanketing the Earth. We just don't yet know how to receive it anymore than someone from the Middle Ages would know how to construct an AM radio receiver.
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