SETI@Home Revisits Its 100 Best Signals

cmbrothe writes "The Planetary Society is running an article about SETI@Home's plan to revisit its 100 most promising signal candidates. The article also outlines the criteria for selecting the candidates."

Comments

Playing the Odds

[Nintendork]

I'm telling myself that it's not going to happen, but what if more than one of those 100 candidates turns out to be the real thing. What a shocker that would be!

I mean, with the amount of planets out there, I'm sure there's a whole lot of life and a lot of intelligent life. It's just that we hope to find one other intelligent race and people aren't even thinking about finding more than that.

-Lucas

Would they detect themselves?

[wowbagger]

While I am a contributor to SETI@home, I have to wonder about the following question:

"Given the rules they place on a signal, would SETI@Home have detected the past attempts we've made to contact other stars?"

Consider the past efforts at Arecibo to send a message to other stars. We focused on one star for a couple of hours, and sent a message. Perhaps we repeated it over the course of a few days.

Now, let us suppose that a civilization with a similar technology to ours was located on a planet around Proxima Centauri, and let us suppose they did exactly as we did in our transmissions at Arecibo. Would that signal have been found by SETI@Home?

Given how the SETI receivers might not have been looking in the right places at the right times to see more than one transmission, might that signal have been discarded because we did not see more than one instance of it?

Re:Would they detect themselves?

[sbaker]

I don't think SETI is sensitive enough to pick up TV signals from even
the nearest stars.

To pick up their TV signals, I think we need a dedicated SETI radio
telescope on the far side of the moon - something a couple of hundred
miles across maybe.

So we are listening for a definite "Hello Earthlings!"
type of signal from a pretty powerful transmitter. Something
containing the prime numbers, the first 100 binary digits of PI,
something like that.

My question is whether any aliens would send such a signal. You'd
be taking one heck of a chance that it won't get picked up by more
advanced civilisations with a penchant for destroying upstart
planets.

It seems to me that most civilisations will be sitting - quietly
listening just like we are.

Are we broadcasting, too?

[Seanasy]

I'm not talking about all the regular satellite communications. Are we intentionally broadcasting any messages for the universe at large?

If, however, the barycentric frequency of a signal remains steady, this almost certainly means that it is designed to compensate for the movements of its own host planet. In other words, it would point to a deliberate intelligent design.

And would regular satellite communications appear barycentric? It doesn't sound like it. So, if we're not broadcasting barycentric signals, why would we expect other lifeforms to broadcast them? Or are we braodcasting something barycentric? Can I tune in?

Re:Are we broadcasting, too?

[Idarubicin]

It's not that SETI@Home is ignoring non-barycentric signals; they are just assigning barycentric signals a higher priority for examination.

This is a pretty reasonable approach, actually. Barycentric signals imply deliberate action. Further, they imply that the signals are intended to be received by someone or something (not necessarily us) beyond the immediate space about the transmitting planet.

SETI@Home is certainly not ignoring non-barycentric signals, they are only prioritizing the (literally) billions of potential 'hits' they have accumulated. I'm quite sure that if we started seeing large gaussians every time Arecibo swung past Proxima Centauri, nobody would ignore them even if the peaks Dopplered a bit from planetary orbital motion.

On the flip side, no--we are not broadcasting any barycentric signals right now. An alien SETI@Centauri project might assign us a slightly lower priority because we're not making a deliberate effort to be noticed. Nevertheless, continuous radio and television signals across multiple frequencies would probably make us quite an interesting target to any race with good enough detectors and large enough dishes.

Re:Window of contact

[Izeickl]

Your opinions are just that, opinions and speculation. Your view is no more valid than that of someone who thinks there is some alien life millions of light years away. Unfortunatly neither arguments can be proven, at least not yet. I would like to think there are other life forms out there, but im not commiting myself to one side or the other as no one knows! As Tommy Lee Jones in MIB said few hundred years ago everyone was -certain- the earth was flat, the earth was centre of the universe etc etc...

Sorry... No.

[SaturnTim]

Sure, if the SETI project gave conclusive proof that there was alien life, It would be a day that would go down in history.

But, it has to be rock solid proof. Not just a signal, we need a communication from another world. Otherwise CNN will have someone on there within the hour making up 50 other possibilities for the signal.

--ST

More info on the top 100

[i8a4re]

There are two things I'd really like to take a look at, and I'm sure I'm not the only one.

First, there is a program that can convert the work unit files into a wav file. I think it would be pretty cool to listen to some of these top 100 signals. I've played with the program on quite a few work units and never been able to hear anything but static. As strong as the top 100 signals are, you should actually be able to hear something.

Second, there are a few places on seti's and related sites that show a picture of what a good signal looks like. Why don't they take a grad student and make him run through the top 100 signals and record what the graphics look like when it is processed?

I've actually emailed them before and requested both of these. I've never gotten a response nor have they posted either. If they have, then I've just missed it.

Re:Window of contact

[sbaker]

There are two aspects to this:

1) Will the shortness of the lives of civilisations reduce the
probability of our detecting a message by so much that we won't
ever see one?

2) If we recieve a signal from a long dead civilisation - then
how will we ever talk with them?

In response to (1): The Drake equation (which estimates the number
of alien civilisations that ought to be out there) takes this into
account - and taking our best guess at that number, we should still
expect to see a significant number of civilisations out there at the
right stage in their life-span to talk to us. Of course there are a
huge number of wild-ass-guesses in that equation - so making any
concrete statements about the result is dangerous.

However we can never know what the typical lifespan of a civilisation
is - because the only planetary civilisation we have any data on hasn't
died out yet!

In response to (2), I have to say that if we could ONLY detect signals
from long-dead civilisations, it would still be worth listening.

Firstly because the mere knowledge of the existance of intelligent
life elsewhere in the universe would justify the search.

Secondly, it's also possible that the transmission would include the
entire Encyclopedia Galactica - so even though the civilisation is
dead, it might pass on knowledge that would pay for SETI a million
times over.

So, whilst the shortness of the lifespan of civilisations is a concern,
it's not a reason not to search.

OK...

[anthony_dipierro]

What are the odds of a random collision of atoms of a certain solar system producing life?

What are the odds of a random string of radio signals mimicking life?

If B>A, we have some problems.