SETI Predicts We'll Find ETs by 2020

FTL writes "Based on the Drake Equation, Moore's Law, and the Allen Telescope, a new prediction has been made that Earth will make first contact with aliens within 20 years. Of course once we find the first aliens there's the question of can we decode their signals, would they spot our reply, and what's the lag time."

Comments

16 years of radio lotto

[Lord Grey]

Within a generation, radio emissions from enough stars will be observed and analysed to find the first alien civilisation, Shostak estimates. But because they will probably be between 200 and 1000 light years away, sending a radio message back will take centuries.

OK, I'm curious. How is this 200-1000 light year estimate derived?

"But predicting the date, the decade or even the century of contact is another matter because the 'other end' of the communications link is completely out of our hands. ..."

Our planet emits enough radio energy to look like a small sun, but it hasn't done so for very long. Some scientists believe that it won't continue at the present level, either, because future requirements will demand higher-capacity transmissions -- radio transmission will fall off in favor of something that's more tightly-focused, in other words.

Making the large assumption that an alien race will go through a similar radio transmission curve, and considering the fact that we don't know how far away said alien civilization is, the chances of us finding them between now and 2020 seems very remote.

Re:To Serve Man

[Kenrod]

For all we know, humans might rank at the cattle level on a galactic scale. You know - really stupid and very, very tasty.

Is SETI Even On The Right Track?

[GoatChunks]

I've been wondering this...and all of you people that think you're smart might be able to figure this out for me. SETI uses radio telescopes to search for E.T., right? Now, I understand that these radio telescopes don't just search for AM/FM radio signals, but basically waves within the full broadcast spectrum. So they're looking for AM/FM, TV, CB, Wi-Fi, wide band, short, wave, cell phones, etc. So I guess the basic thinking is that any intelligent race will use radio signals of some sort. How long have humans been using some kind of radio signals? In the general scheme of things, a very brief time. How much longer will we be using them? Is this something that will be with us forever, or will it die out as our technology advances? Assuming our technology will advance, somehow, to exclude broadcast signals, our planet, from space, will become rather quiet. Also assuming that all intelligent life evolves along a similar timeline, we can assume that these other planets will emit radio signals for only a brief period of time. But somehow we're assuming that that time will somehow coincide with our own. It makes finding a needle in a haystack even harder when the damned needle keeps moving around. Enlighten me. How can SETI possibly work? (That said, I do have the SETI@Home software running on all of my machines...so I'm hopeful.)

Re:Is SETI Even On The Right Track?

[NanoGator]

"How can SETI possibly work?"

Maybe because radio emissions aren't necessarily a result of communication? Lots of machinery generates RF, that's why the FCC has to approve electronic stuff in the USA before it's released.

"Also assuming that all intelligent life evolves along a similar timeline, we can assume that these other planets will emit radio signals for only a brief period of time."

We can't assume anything, we haven't met anybody else. Besides, even if we invent sub-space inverse tachyon communicators, who's to say radio would ever die out? It'll always be useful for something.

I agree it's a long shot, but what's the harm in looking? Dismissing stuff is a lot easier than searching for what might not exist. Life would be more primitive here if the former happened routinely.

Re:I don't get these kinds of predictions

[reezle]

I read a book when I was 8 that said we'd contact aliens by 2010-2015. I've been holding my breath ever since. They also wrote about the flying cars, moon bases, and solar power satellites that we've been enjoying these past 4 years or so... I just wish I didn't live in such a back-waters part of the country that's still driving around on 4 tyres.

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[account_deleted]

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Re:Prediction, or Guess?

[Surt]

Yes, you have to try to pick valid values for the variables, however, many of the variables are rapidly becoming well defined:

http://www.activemind.com/Mysterious/Topics/SETI /d rake_equation.html

If we consider only our galaxy:

N = N* fp ne fl fi fc fL

of which we have answers for

N* = number of stars in galaxy (~100billion)

fp = fraction with planets (at least ~20%)

ne = number planets per star that can spawn life (???)

fl = fraction on which life evolves (??? but if we discover life evolved on mars and earth separately we'll have to assume this is reasonably large, so this might be settled soon)

fi = % where intelligent life evolves (???)

fc = % which communicate (???)

fL = % of planetary lifetime during which communication takes place (currently we can assume this is a small non-zero value, and the longer we use radio waves the larger we can assume this value is).

fp is rising rapidly as we discover more and more extrasolar planets.

fL is rising steadily as our radio emitting civilization persists.

ne may be more accurately guessable once we find out if mars, venus or europa harbor or ever harbored life.

The key to the drake equation is that N* is a very very big number. And now that we know fp is not small (up to a few years ago many people argued that fp would be close to 0) we know that the other fractions need to be quite tiny to avoid having radio communicating civilizations other than our own around.

Re:Or, there could be no aliens to contact..

[StrawberryFrog]

The exponential nature of tech growth implies that we are like apes to a civilization even 100 years ahead of us,

Many of the key results of the 20th century involve the limits of what we can do. Godel incompleteness, and the speed of light to name two big ones. There is no indication at all that any civilisation, no matter how advanced, will be able to overcome the lightspeed problem and make us look like ants.

technology to visit the entire universe at will ("c"restrictions from the current physics knowledge notwithstanding).

You want the lightspeed thing to go away, don't you? Unfortunately wanting counts for nothing, and there's not a shred of evidence for that, and plenty against. Even given nigh-infinite knowledge, physical limits are physical limits.

Many, including me, believe that within about 100 years, a civilization like our would have the technology to visit the entire universe at will

It's entirely possible that a civilisation like our will, in 100 years, have A-bombed, bio-plauged, chemically poisoned or just polluted itself back to the early stone age. Or worse, wiped itself out entirely. I'm all for progress, but dude, go easy on the prozac.

Re:Not convinced

[GlassHeart]

the research that I read made it seems as if we are unique to the point where having billions of galaxys would make little differnce.

No, what we lack is precise knowledge that the earth is special. That is, we don't know the probability by which a planet has a big moon, or that it is near enough a star to sustain life. We don't know the very parameters of life, except that it exists on earth in great varieties.

Absent this knowledge, it is incorrect to assume that the earth is special, any more than a lottery winner should see herself as (too) special. If you only know of one lottery winner, then you'll be misled as to how often somebody wins the lottery if you try to extrapolate based on that ignorance.

The correct approach is to assume that we are one instance of random behavior, that the earth just happened to be so far from the sun, that we just happened to have a big moon, that we just happened to not have collided (yet) with another big object. We are likely a very special planet, but we really have very little clue whether we are special enough to claim exclusivity.

Once you accept this randomness assumption, then the probability of life (and therefore intelligent life) on another planet is entirely a matter of how many planets there are out there. The more, the likelier.

Remember that if you're a one-in-a-million kind of guy, there are more than 1,000 people in China alone just like you.

Not enough signal strength

[Doug Merritt]

I'm a big fan of SETI, but they tend to downplay the fact that we're only likely to be able to pick up signals beamed directly at us.

We can't currently pick up ET signals equivalent to what Earth is broadcasting to space, even if they were coming from Alpha Centauri; they're just too weak.

This is an analog problem of signal to noise ratio, far more than anything else, so faster processing won't help a bit.

A cryogenic Allen array (to minimize thermal noise), especially in space far from Earth, or on the far side of the moon, would help a tremendous amount.

Usually discussions about SETI itself don't bring that up, because of issues of optimism and such, but it was easy to find web hits on the eseentially identical question: can ETs pick up Earth signals?

"No", says this Seti League guest editorial "ET Detection of Earth TV Unlikely" that goes into a little technical detail.

Similar comments by John Dreher, Staff Astronomer, SETI Institute, although he goes on to assume that ETs would be able to pick up weaker signals than humans are able to -- assuming implicitly that ETs will have better analog technology than we do (maybe they do, but that doesn't help us to do the same).

What about ETs actually beaming a signal at us? Maybe they do so to all nearby stars, one by one. Maybe...would we do that?

"...it has been agreed by all relevant groups that we should not be actively sending out messages to try to reach other civilisations", says another page

Ok, so we would not be so foolish as to attract undue attention from an unknown and possibly hostile galaxy, but maybe ETs will be more naive than that. Or a lot more confident (play ominous music here ;-)

So, bottom line, this is a cool topic, but are we planning to build a cryogenic Allen array in space in the next two decades?

I think we should, but any predictions really should be based largely on that one issue.

P.S. the recent lab verification of photons having orbital angular momentum, able to carry arbitrary amounts of information per photon, implies a new medium we'll need to check for ET signals. Maybe that's what all advanced civilizations use.

See e.g. Photons Spin More Data