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Jill Tarter and the Allen Telescope Array
An anonymous reader writes "Today's interview with Jill Tarter of the SETI Institute (and Carl Sagan's inspiration for the main character of his novel Contact), outlines the forthcoming search capabilities of the large Allen Telescope Array. Their thousand-fold expanded search must find promising places to point 350 radio dishes. Outside San Francisco, the array spans an equivalent 8 football fields. Their new catalog, called HabCat, identifies all potentially habitable hosts for complex life within 450 light-years from Earth. Of the billions of places to point in the sky, their A-list total: 17,129. Start at Vega."
Wouldn't it be much more likely that a society advanced enough to be detectable across the vast reaches of interstellar space would find humans based upon primitive radio frequency transmissions? We might be able to just kick back and hope for our sake they don't take any of those hitler or vietnam broadcasts too seriously...
While the possibility of extra-terrestrial life is a fascinating one, aren't there a lot more equally fascinating yet infinitely more practical aspects of space exploration to spend tons of money on?
-bcollier06
First off, we have gotten past our moon with our manless space exploration.
Secondly, just because we discover a signal coming from a planet 450 light years away doesn't mean we have to go there. The knowledge contained in that signal would be enough to warrant such cataloging. If that civilization is anything like ours, they might think to broadcast an "encyclopedia galactica" like Brian McConnell suggests in his book Beyond Contact.
Would you consider yourself a determined believer that extra-terrestrials exist? If (for the sake of discussion) you were to determine that we were, without a doubt the only life in the Universe, how would that impact any religious beliefs you may hold?
I personally believe that if we were to be the only life in the Universe that this would be divine intervention simply because of the statistics, would you agree?
Authors routinely deny claims like this because they are afraid of being sued.
Actually, there are more assumptions made than that. They are assuming that the lifeforms have developed radio technology as a form of communication, which could also be seen as an evolution of the ears/mouth that we have.
Really, though, what it comes down to is this - the universe is REALLY, REALLY, REALLY big. And the amount of time they have to scan it is REALLY, REALLY, REALLY small. So what they're doing is deciding which planets to scan first. Since we have no idea what other platforms that life could have evolved on, the safest bet is to use that short amount of time is to scan those which are similar to our own. The idea being that we DO know what kind of variables were able to sustain life here.
In the future, I think you'll see they'll expand their searching, as technology improves and our understanding increases.
There is more to it than that. Biochemists have done substantial analysis regarding what other chemical families might support life. It looks as though with the periodic table as it is, carbon is the only good choice for rich biochemistry. For carbon life to develop, liquid water appears necessary. So, you have narrowed the search volume considerably by only considering stars that would likely have a planet in the "liquid water" sweet spot, while not getting fried by hard radiation at the same time.
Further, a planet must exist long enough for evolution to occur. That eliminates a great number of stars as well - many just don't last long enough.
As another poster pointed out, that at least provides a starting point on where to look.
Galileo: "The Earth revolves around the Sun!"
Score: -1 100% Flamebait
And I'm not only talking about the software: Philosophy, culture etc. - which are also significant; as our history demonstrates, culturally underdeveloped civilizations tend to lose interest in space travel. We're already making small steps in interfacing chips with wetware. Any civilization that is sufficiently advanced for interstellar travel also has the technology to enhance its own thinking abilities beyond our current understanding.
What, then, would be the motivation for such a spacefaring civilization to attack another? Resources? Hardly. The energy requirements to get those resources are much higher than the value of the resources themselves, and if these energy requirements can be overcome, you are no longer dealing with a resource-dependent civilization anyway -- you have nanotechnology, molecular assemblers etc. Blind hatred? A product of our primitive reptile brains, in spite of what Star Trek may have taught you (Klingons! Painsticks!), it is very unlikely that a civilization on that level would still be guided by such emotions, which could be turned off on demand using the same neuro-interfacing technology that also enhances rational thinking. Threat eliminiation? Earth a threat? Only to ourselves. The Day the Earth Stood Still was nice, but nuclear technology isn't exactly going to turn us into an intergalactic pariah as the movie predicted.
No, the one motivation that will guide such civilizations is simple: information. They will want to learn about other worlds, other cultures, other planets. But they will not want to interfere with these cultures, for two reasons:
So, if interstellar travel is possible and desirable (let's not even talk about all the relativity issues involved), aliens would most likely only watch. If it isn't, they would listen using huge (solar system sized?) radio telescopes. But they certainly wouldn't start "punishment" missions in order to eliminate "inferior" civilizations -- these are primitive motivations that are not rationally justifiable.
It is by no means "must" - it is simply considered most likely. The scientists are going with the best probabilities based on, surprise, the science we know.
For all we know, the universe could be full of intelligent life based, not on chemical interactions, but on quantum interactions, or perhaps complex interactions of particles based on gravity, or perhaps some subtle physical effect we don't even know about yet.
If the universe is "full" of such life, it is not transmitting in the radio spectrum - we've already looked quite a few places, including empty space. There are fairly "obvious" physics-based frequencies at which to transmit, if you wish to communicate. If you don't wish to communicate, that is another kettle of fish...
It is not that we haven't already listened in lots of directions, and to lots of things. So far, radio hasn't proven very fruitful.
It may be that there is a instantaneous-super-quantum-gravitational-string (or something) form of communication that almost all civilizations acquire at some point beyond our current technology. That would certainly account for a large-scale radio silence. Of course, there are numerous other possibilities.
Galileo: "The Earth revolves around the Sun!"
Score: -1 100% Flamebait
This is based on the analysis of one single biosphere. Again, generalizations based on a sample set of one.
No, it is based on the analysis of every chemical in the universe, most likely. This is confirmed by astrospectroscopy.
The possible chemical interactions of these elements are well understood. Only carbon permits sufficiently complex molecules, with other important attributes like flexibility. Silicon, a closely related element, is the nearest in suitability, but it is much more limited.
And you have excluded planets that are really no less likely to have "life" than the ones you are keeping in your list.
I disagree.
This is an even wilder assumption (unwarranted generalization). To attempt to apply the number of years that something took place on Earth to other planets and other systems we know nothing about.
The Earth existed for around 1.5-2 billion years before it was remotely suitable for life. These are mostly straightforward physical processes such as cooling and atmosphere formation.
Many of the brighter stars you can see in the night sky have total lifespans before extinction of less than one billion years. Others are so variable as to produce very unsuitable conditions for carbon based lifeforms. Others are in multiple star systems where stable planetary orbits are impossible.
These are largely the types of systems that have been eliminated from the initial search (emphasis mine).
The best candidate stars will be from the F, G, K, and M classes of stars. See the Hertzsprung-Russel Chart
If you are looking for intelligent life out there, throwing a dart at a star chart while blindfolded makes as much sense.
Nope. See above.
What you are doing might make sense if you are looking for the Trekkie "class M" planet with the afro alien chicks with go-go boots.
It'll be very interesting how close alien "DNA" is to terrestrial DNA. It is quite a stretch to think that carbon-based, intelligent aliens would even be bipedal, much less humanoid. I'd suggest that the variety of life on Earth argues otherwise, and that the octopus is arguably the second best design for intelligent life on this planet (other than the Great Apes).
Think how different life on Earth might be if the some of the early extinction events hadn't occurred here. For instance, the Permo-Triassic Extinction. A brief quote:
"Over a span of 5-10 million years, it is estimated that between 75 and 90 percent of all preexisting species were lost, including 80-96% of all marine species and approximately 57% of all marine families."
However, shouldn't the goal be too look for life, rather than just a much more limited and unlikely type of life?
All the evidence suggests that other types of life are likely to be "more limited and unlikely". That is exactly the point.
Galileo: "The Earth revolves around the Sun!"
Score: -1 100% Flamebait