Posted on 07/16/2002 7:40:55 AM PDT by Momaw Nadon
CANBERRA (Reuters) - Scientists searching the stars for aliens are convinced an E.T. is out there -- it's just that they haven't had the know-how to detect such a being.
But now technological advances have opened the way for scientists to check millions of previously unknown star systems, dramatically increasing the chances of finding intelligent life in outer space in the next 25 years, the world's largest private extraterrestrial agency believes.
"We're looking for needles in the haystack that is our galaxy, but there could be thousands of needles out there," Seth Shostak, the senior astronomer at California's non-profit Search for Extraterrestrial Intelligence ( news - web sites) (SETI) Institute, told Reuters in an interview on Tuesday.
"If that's the case, with the number of new star systems we now hope to check, we should find one of those in the next 25 years."
But Shostak, visiting Australia to attend a conference on extraterrestrial research, said detecting alien life, like the big-eyed alien in the film E.T., was only the start.
"Even if we detect life out there, we'll still know nothing about what form of life we have detected and I doubt they'll be able -- or want -- to communicate with us," Shostak said.
Since it was founded in 1984, the SETI Institute has monitored radio signals, hoping to pick up a transmission from outer space. Its Project Phoenix conducts two annual three-week sessions on a radio telescope at Arecibo, Puerto Rico.
Project Phoenix, widely seen as the inspiration for the 1997 film "Contact" starring Jodie Foster, which depicted a search for life beyond earth, is the privately funded successor to an original NASA ( news - web sites) program that was canceled in 1993 amid much skepticism by the U.S. Congress.
But the search has been slow. About 500 of 1,000 targeted stars have been examined -- and no extraterrestrial transmissions have been detected.
E.T. NOT ON THE LINE
"We do get signals all the time but when checked out they have all been human made...and are not from E.T., more AT&T," said Shostak.
He said the privately-funded institute was developing a giant US$26 million telescope to start operating in 2005 that can search the stars for signals at least 100 times faster.
The so-called Allen Telescope Array, named after sponsor and Microsoft co-founder Paul Allen, is a network of more than 350, six-meter (20-foot) satellite dishes with a collecting area exceeding that of a 100-meter (338-foot) telescope.
The Allen array, to be built at the Hat Creek Observatory about 290 miles northeast of San Fransciso, will also expand the institute's stellar reconnaissance to 100,000 or even one million nearby stars, searching 24 hours a day, seven days a week.
Shostak said he is convinced there is intelligent life out there -- but don't expect to find a loveable, boggle-eyed E.T..
He said if any aliens share the same carbon-based organic chemistry as humans, they would probably have a central processing system, eyes, a mouth or two, legs and some form of reproduction.
But Shostak thinks any intelligent extraterrestrial life will have gone light years beyond the intelligence of man.
"What we are more likely to hear will be so far beyond our own level that it might not be biological anymore but some artificial form of life," he said. "Don't expect a blobby, squishy alien to be on the end of the line."
I have studied your reponse to determine if it is as polite as is possible for the average intellect, and it appears to my casual eye to be about as arch and snarky as the rest of your offerings, so it seems to have failed that test, as well.
On January 1, 3000, a tachyon beam signal, travelling at four times the speed of light, is sent from Earth towards the starship Tempus Fugitive. The message is "Ping!" At the time the message is sent, the ship is 0.8 light years from Earth, travelling at a speed of 0.8 times the speed of light.
By the time the tachyon signal reaches the starship, it is 1 light year away, as measured from the Earth. But on the Tempus Fugitive, the Earth is only 0.6 light years away (Lorentz contraction).
The date of this event is April 1, 3000, as measured on Earth. But in the reference frame of the starship, this event is contemporaneous with events taking place just after noon on September 3, 2999 on Earth (frame dependence of simultaneity). [Geek alert: t' = gamma*t - L*beta*gamma/c; if t=0.25 years and L=1 l.y., beta=v/c=0.8, and gamma=1/sqrt(1-beta^2)=0.6, then t'=-0.33 years.]
The Tempus Fugitive replies with an "Ack!" upon receipt of the message. It takes .15 years for the signal to traverse that distance, but the Earth is travelling away from the starship at .8 c, so the signal takes .1875 years or 68.4 days for the signal to reach Earth. But in the starship's frame of reference, time on Earth is moving only at .6 its regular speed, so only 41 days pass there (time dilation). The return signal arrives on Earth on October 14, 2999.
This same sort of analysis will work for any signal moving faster than the speed of light. For a signal that is only moving slightly faster than light, the traveller will have to be moving extremely close to the speed of light in order to take advantage of such endochronic properties (egads, another "snide" science fiction reference, Asimov this time), but it can be done in principle. Counterintuitively, the farther away is the traveller, the farther back in time the signal is projected (again, provided he is moving fast enough to do it at all).
By the time the tachyon signal reaches the starship, it is 1 light year away, as measured from the Earth. But on the Tempus Fugitive, the Earth is only 0.6 light years away (Lorentz contraction).
Hold on The ship is only .6 lt yrs away? Lemme see. For a velocity of .8 of c, gamma is roughly 1.66 (I'm doing this on a slide rule, setting .8 on the P scale, reading 1.66 on the DI scale). Lengths are determined by the reciprocal of that, found on the D scale, or .6. Hmmmm, you did say the ship is .6 light years away ... okay, grumble, grumble. Geek check is affirmative. (I love doing Lorentz transforms on a slide rule. Fastest method in existence.)
Well, that's OK, you've pointed out another error on my part: when I went to calculate the simultaneity, I gave gamma as 0.6, not 1.66 (must've fumbled the "1/x" button on my calculator; serves me right for shooting from the hip). So the signal will arrive even earlier than I said.
Ah, well. Being a physicist means, among other things, that I make (and have made) more physics mistakes than most people.
Yes, that's right. ;^)
I didn't check the dates. (Not geeky enough.) But seriously, a slide rule is much faster than anything else for computing gamma.
Let's say you take off from earth in a ship that travels around 99% of lightspeed, fast enough for you to experience the effects of time dilation. And before you take off, you synchronize clocks with your buddy back home (synchronized clocks are a standard bit of equipment in these thought experiments). You've also got that mythical "subspace radio" which keeps you in instantaneous contact with earth. In due course, I shall demonstrate the impossibility of that device.Okay, as you accelerate to 99% of lightspeed, less time is passing on ship than back home. You're not aging as rapidly as you would if you stayed home. This is apparent only in comparison with earth, however. On the ship you notice nothing odd. But your once-synchronized clocks are no longer in sync. Yours is now showing less time passing than the clock on earth (from earth's point of view). This is standard stuff, plain old special relativity.
After a while, let's say your ship clock is a day behind the earth clock (never earlier than launch date, however, as that would be quite impossible. The divergence commences after that point). Now you receive a message from earth: "Terrible news! President Hillary Clinton assasinated! USA in mourning." This message comes over your "subspace" radio, so it's an instantaneous communication. However ... you have accelerated away from earth, so your clocks now register an earlier time than that on earth. If the message is sent on earth's July 4th, you receive it on your ships's July 3d. Okay. You're still with me, right? Get this next point, because it'll make your brain ache. Because of the acceleration between the two reference frames, the sender's clock is later than the receiver's clock. This is always going to be true -- in all reference frames.
Now you get on the supspace radio and send your condolences back to earth: "So sorry to learn of the July 4th assasination of President Hillary Clinton." Ah, but here comes the catch. You are sending this message on your July 3d. Because of your acceleration away from earth, from your point of view -- which is just as valid as earth's viewpoint -- it's earlier on earth than it is on your ship. So your message travels instantly and gets to earth on July 2nd. Earth's July 2nd. And they now know of the event before it happened.
No, you say. Why would it get to earth earlier? Why? Because earth's message got to you earlier than it was sent, and it always gets where it's going earlier than it was sent. There are no privileged reference frames. From the point of view of your ship, earth accelerated away from you and is experiencing its own time dilation effect. It works both ways.
So your subspace radio allows messages to be sent into the past, which generates all kinds of paradoxes; and it is generally accepted that no such contrivance is possible. One of the advantages of a lightspeed limit is that it keeps the universe from going crazy.
Just as well. It would have been taken for a joke, otherwise.
Because of the acceleration between the two reference frames,
I would rephrase this as "because of the relative velocity between the two reference frames".
USA in mourning
This is a more serious error. :-)
Only if you like money. ;^)
I don't recall, but that's quite likely.
Thanks for posting it.
So, if today (Earth time), I sent a signal beam of today's winning lottery numbers to a reflector a sufficient distance away from the Earth at a FTL speed, would I receive back the reflection of the message of today's winning lottery numbers before today(Earth time)?
You don't get out much.
It isn't any more close-minded than "God doesn't exist," which might as well be tattooed on the foreheads of the many, many atheists who clog up FR with mounds of mouldering mind manure each meandering minute.
We are the center of the universe, incidentally. We are also the edge of it. There is no privileged place spatially in the universe.
The astonishing conditions that must necessarily coalesce in in this particular planet, this particular solar system, this particular galaxy, and this particular universe to allow for mankind to exist at all makes our existence very, very, very special indeed. The odds against such conditions arising randomly are so prohibitive as to be essentially infinite. The time required to allow such odds to play out exceed the approximate 15 billion year age of the universe by many, many orders of magnitude.
It is our uniqueness that really troubles the atheists. It's what fuels their obsession to look for life elsewhere--to eagerly embrace and employ intelligent design strategies in the SETI context that they hypocritically ridicule and call phoney science when believers embrace and employ it. The Christian biblical account implies our uniqueness. It makes the astonishing claim that the Creator of the universe Himself manifested His presence in the flesh in this place at this time to offer mankind a more magnificent life and a permanant consciousness such as HE enjoys.
No, the biblical account doesn't necessarily say or imply that God has not allowed life to arise elsewhere. But God-haters and atheists would be greatly relieved to discern intelligent outside our solar system. They believe it would further undermine the special claims of Christianity--and that is very important to them.
For if the special claims of Christianity are true, all men--including atheists--are accountable to God for the lives and bodies that God created. The self-worshipping have no desire to face that judgment.
It would devastate you if you knew how unimportant that is to SETI proponents.
Toohey: Why don't you tell me what you think of me?
Roark: But I don't think of you.
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