How long til we find ETs?

[zakur]

22 years, according to some:

Earthlings, get ready for space visitors

The leading experts in the search for extraterrestrial intelligence at the SETI Institute in Mountain View, Calif., recently completed the most systematic calculations ever performed on when the human race is likely to contact intelligent alien life for the first time.

Their answer: within 22 years.

And they suspect that our first interstellar interlocutor might end up being a super-intelligent machine rather than anything biological.

Seth Shostak unveiled SETI's predictions at an astronomy conference in Germany earlier this month. He and co-author Alexandra Barnett will go public with their findings Saturday when their new book, "Cosmic Company: The Search for Life in the Universe," is published.

"There are as many stars in the universe as there are grains of sand on Earth's beaches," said H. Paul Shuch, executive director of the SETI League Inc. "About 10 percent may have planets with intelligent life. That's your haystack.

"We investigated the rate at which astronomers will be scanning those stars for radio signals, and concluded that it will take about one generation to find the needle."

Shuch, who attended Shostak's presentation in Germany, nevertheless joined other scientists in chiding Shostak for so starkly predicting first contact by 2025.

"My respected colleague should know better," Shuch said. "It is safe to say that by 2025, our newest and greatest SETI technology will have been up and running long enough to make a detection -- if."

"Ifs" include: that extraterrestrial life exists in detectable civilizations relatively close to Earth that are still primitive enough to use radio signals.

Is Vegas running odds on this? Hell, if you can bet on the coin flip before a Super Bowl, why not the discovery of ETs?

 

[T'ai Chi]

So if nothing by 2025, will they stop looking because of massive lack of evidence?

 

[Interesting Ian]

22 years, according to some:

I doubt it. If you're talking about intelligent self-conscious beings I would estimate thousands of years. I think it is possible that primitive life exists in our solar system though, I mean apart from on the earth.

 

[zer0vector]

"We investigated the rate at which astronomers will be scanning those stars for radio signals, and concluded that it will take about one generation to find the needle."

I have a slight problem with this statement. Assuming they're talking about actual radio astronomers here, the process by which they do their observations makes detection of a signal usually impossible. During a standard observation, the signal is integrated, meaning on the whole, any time variable amplitude changes will be averaged out.

Of course by "astronomers" they could mean SETI specific searchers, in which case the problem becomes lack of access to large powerful radio telescopes.

 

[Correa Neto]

There is a problem with the SETI approach. It presumes that:

(1) An alien civilization is actively willing to make contact with us, sending signals and/or
(2) An alien civilization scatters as much radio energy as we do.

Both can be disputed. One could ask if a an alien civilization would really want to contact us. And also, one should consider the possibility that an alien civilization (even in the improbable case of an alien civilization that has a technological level roughly similar to ours) may use slightly different technologies then ours for communications (ex. more intensive use of cable, colimated radio beams, laser, etc). In this last case, they would emmit smaller ammounts of radio energy.

So, even if they do not find a signal, it will not be final proof that we are alone in this part of the galaxy.

 

[Hypocolius]

Re: Re: How long til we find ETs?

I doubt it. If you're talking about intelligent self-conscious beings I would estimate thousands of years. I think it is possible that primitive life exists in our solar system though, I mean apart from on the earth.

I'd agree, except I'm not sure I'd bet on it existing in our Solar System. Our galaxy, yes, solar system hmmm.... dunno.

 

[Hamish]

I've been wondering whether it is actually possible to observe our radio traffic from another star system. The reason being, we may be looking but why should we ever expext other civilizations to send out dedicated contact signals when we refuse to do the same? What if everyone in the galaxy is keeping really quiet, metaphorically cupping a hand to one ear (or auricular organ of your choice)?

So after a short bit of digging, I was pleased to find this linked from the SETI website:

Can Aliens Find Us?

According to this:

A modern TV transmitter can put out as much as a megawatt of power. It’s not very tightly focused, so even though much of the broadcast energy spills into space, it’s fairly weak by the time it reaches another star system. Consider one of our early TV programs just washing over a planet that’s 50 light-years’ away. To detect the "carrier" signal from this broadcast in a few minutes’ time would require about 3,000 acres of rooftop antennas connected to a sensitive receiver. That’s a lot of antennas, and an unsightly concept. But it’s not hard to build, and the aliens could conceivably do it. If the extraterrestrials were unwise enough to actually want to see the program, then they’d need an antenna about 30,000 times greater in area (roughly the size of Colorado). Ambitious, but possible

Ambitious? Try getting a research grant for that! But not to worry. Apparently, military radar shines out like a beacon across space:

There are enough such radars that, at any given time, they cover a percent of the sky or so. The signal from the most powerful of these could be found at 50 light-years’ distance in a few minutes time with a receiving antenna 1,000 feet in diameter. Indeed, these military radars are the only signals routinely transmitted from Earth that are intense enough to be detectable at interstellar distances with setups equivalent to our own SETI experiments.

But that leaves us, as the article points out, detectable up to 50 light years away. And those signals probably won't have got that far yet. And there isn't much chance of finding ET within 50 light years. We can only hope that they're shouting louder than we are.

 

[Agammamon]

While I agree that if we make contact with aliens it will probably be a super intelligent machine I wonder how the got the data for the 22 year prediction. Since we have no idea how prevalent life is let alone intelligent life nor whether any of these people are sending out high powered broadcasts (we're not). What it sounds like is someone plugged a bunch of numbers that sounded good into Drake's equation.

The radars mentioned in that article aren't likely to be on all the time and sending energy off in all sorts of directions, I don't think these things would be radiating in on direction long enough. Also they seem to discount the interference from other radio sources like Jupiter and the Sun.

 

[Hamish]

Apparently, we have sent a signal. Not really a shout as a tentative murmur. From the original article URL=http://seattlepi.nwsource.com/n...epi.nwsource.com/national/146040_alien30.html:

Earthlings also have tried to reach out to extraterrestrials.

In 1974, the Arecibo Observatory in Puerto Rico, the largest radio telescope in the world, sent a digital message toward the M13 Global Cluster. It will arrive in about 25,000 years.

The Pioneer 10 spacecraft launched in 1972 carried a plaque bearing an illustration of a man and a woman and a diagram identifying Earth's location in the galaxy. It is now 9 billion miles away.

Well, the Arecibo thing seems a bit pathetic. One might try for something a bit more short term than that. Something that might actually reach its destination and recieve a reply within a century or two. As for the Pioneer spacecraft, that hasn't even passed through the Oort cloud yet. And seriously, what are the odds of another civilisation ever finding it? For all we know, the solar system could be filled with Pioneer-sized probes from alien civilizations but since the batteries all went flat several millennia ago, we can't see them at all. They wouldn't be emitting anything and would be too small to see by radar or optical telescope. Hell, we keep finding new moons round the outer planets and they're pretty big.

But anyway, back to the original discussion. Yes, Agammamon, it does look like just another set of best guesses plugged into the Drake equation. Most of the terms in this are only going to be best guesses to within an order of magnitude. Several of the terms really can be varied over three or four orders of magnitude depending on your level of optimism. Then you get anywhere from "7pm tonight" to "not in the next 3 billion years" as the estimate of the time taken to make contact.

Place your bets now.

(Edited for spelling)

 

[peptoabysmal]

well, of course. SETI has to justify it's existance, which a part of would be making a guess on when the "project" will be complete (i.e.; success). I'll bet that my guess is just as good as theirs.

 

[Larspeart]

1st, I'll state that I do have SETI@home on my computer at home as my screensaver.

Now, I will say that I personally do not believe in aliens 9at least in the intelligent sense), and even if I did allow that they could exist, I strongly feel that SETI's approach to finding them is all wrong.

Humans are VERY conceited, and VERY arrogant. We believe that our way isthe best, andthe only way. We believe that because we discovered radio waves, so would other life forms. We believe that other life forms will develop equipment capable of listening for our stuff, and for broadcasting their stuff back to us. HIGHLY unlikely.

I doubt that we will EVER find other forms of intelligent life. Shoudl the human race live another 100,000 years, I still think that we will be searching for it. Now, don't get me wrong. I woudl LOVE to be proven otherwise (hence my screensaver, lol), but I honestly do not see it.

Now, UNintelligent life? I am sure it has developed in some sense of another by accident before, maybe even in our own solar system. Again, when I am SHOWN it, I'll believe it.

 

[Interesting Ian]

1st, I'll state that I do have SETI@home on my computer at home as my screensaver.

Now, I will say that I personally do not believe in aliens 9at least in the intelligent sense),

You mean in the whole Universe?? We don't know how big the Universe is and therefore cannot say the existence of other intelligent life is unlikely. We know that it is possible for consciousness to arise, because it has done on our own planet. No matter how unlikely we might judge this event to have been, we might still suppose intelligent life is likely elsewhere in the Universe if the Universe is sufficiently large. Perhaps you meant no intelligent life elsewhere in our galaxy?

I feel the Universe is teeming with life. But I feel intelligent life will be very rare, and that intelligent life with technology will be that much rarer still. I say thousands of years before we find intelligent life. Basically we need to go to the stars to find them.

 

[Agammamon]

Well it does seem that intelligent life is rare in this galaxy. Even travelling at a fraction of c piddling little meat puppets could terraform/colonize pretty much the whole galaxy in a couple of million years, which isn't long in the lifetime of a species.

 

[Wile E. Coyote]

The chances are very small that we will find intelligent life any time soon. Humans have been around for two million years and have only had the ability to send and receive radio signals into space for the last 50 years.

The probability that another star system have the right conditions for life are pretty small. For intelligent life: even smaller. Near us: whoah, where did it go? In the same million years as us: Hah!

SETI is a noble effort, but it gains us nothing. It's chance of success is so infinitismal that it is practically fantasy. Still, it is a beautiful dream.

 

[wollery]

Now, I will say that I personally do not believe in aliens 9at least in the intelligent sense), and even if I did allow that they could exist, I strongly feel that SETI's approach to finding them is all wrong.

Humans are VERY conceited, and VERY arrogant. We believe that our way isthe best, andthe only way. We believe that because we discovered radio waves, so would other life forms. We believe that other life forms will develop equipment capable of listening for our stuff, and for broadcasting their stuff back to us. HIGHLY unlikely.

I doubt that we will EVER find other forms of intelligent life. Shoudl the human race live another 100,000 years, I still think that we will be searching for it. Now, don't get me wrong. I woudl LOVE to be proven otherwise (hence my screensaver, lol), but I honestly do not see it.

Now, UNintelligent life? I am sure it has developed in some sense of another by accident before, maybe even in our own solar system. Again, when I am SHOWN it, I'll believe it.

In answer to the radio wave thing, can you think of any other way of sending messages or data over large distances, through walls and round corners, without wires? If you want to use EM radiation then the radio band is by far the best, it's only stopped by pretty thick rock or metal. Microwaves are too strongly attenuated by the atmosphere to be of use for anything but relatively short distances, whilst the rest of the EM spectrum either interacts far too much with anything in it's path (submm, IR, optical & UV) or requires huge amounts of energy and is harmful to living things (X-rays & gamma rays). Furthermore SETI aren't expecting to understand the signal (should they get one), merely to recognize it for what it is - a non repeating modulated carrier wave.

However, I have to agree that SETI is an exercise in futility. To have any chance of hearing the signal we'd need much larger radio telescopes and far fewer targets to point them at. The second problem will be addressed in the not too distant future when projects such as TPF (Terrestrial Planet Finder) get off the ground.

I firmly believe that there is intelligent life on other planets in the universe, but I have no idea whether or not we'll ever find it.

 

[PygmyPlaidGiraffe]

Well it does seem that intelligent life is rare in this galaxy. Even travelling at a fraction of c piddling little meat puppets could terraform/colonize pretty much the whole galaxy in a couple of million years, which isn't long in the lifetime of a species.

Originally posted by Interesting Ian
Basically we need to go to the stars to find them.

if human beings did go out to colonise others planets in our solar system and in systems throughout the galaxy, wouldn't those human's be the Extra Terestrials?

Where are the Martians? Humans that colonised Mars would become the Martians.

must credit Ray Bradbury's Martian Chronicles for that perspective