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."

Comments

Re:Wow Signal.

[richie2000]

This article was linked from the article in the post.

Excerpt:

In the October 20 issue of The Astrophysical Journal, Gray and Simon Ellingsen, of Australia's University of Tasmania, report on new observations (partially supported by the SETI Institute) designed to test this idea. Their new try was made at the 26-meter radio telescope in Hobart, Tasmania. This southern hemisphere instrument could continuously follow for most of a day the patch of sky (in the constellation of Sagittarius) where the "Big Ear" was pointing when it found the 'Wow' signal. They made six 14-hour observations, and even though their telescope was rather smaller than the venerable Ohio State antenna, they still had sufficient sensitivity to find signals only 5% as strong as Wow's 1977 intensity. They also covered five times as much of the radio dial as the original "Big Ear" telescope.

Bottom line? No dice. To quote from their article, "no signals resembling the Ohio State Wow were detected..." Of course, if the signal's repetition cycle were much longer than 14 hours, then even this careful experiment could have easily missed it. But as Gray and Ellingsen point out, if the signal were really this infrequent, then the chance to have found it in the first place was very slim.

So was the Wow signal our first detection of extraterrestrials? It might have been, but no scientist would make such a claim. Scientific experiment is inherently, and rightly, skeptical. This isn't just a sour attitude; it's the only way to avoid routinely fooling yourself. So until and unless the cosmic beep measured in Ohio is found again, the Wow signal will remain a What signal.

Re:Looking at the tools...

[vofka]

Have a look at This Introduction to Very Long Baseline Interferometry at the Jodrell Bank Obervatory website - that will tell you (almost) everything you ever wanted to know about VLBI, and then some!!

Cool article, cool web page

[Omega1045]

While I am a huge SETI fan, I immediately noticed the menu system at the top of the Astrobiology Magazine website. It gives the user of the site the ability to email the story, fax it, download it in Word, Acrobat or PalmDoc, or make it printer friendly. Among other options, it also will translate to Spanish, and read the article to you in MP3.

A lot of work, I think kudos should be given to the web dev team that put this site together. Very cool site!

What else would you suggest?

[robinw]

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.

Re:In some ways, the catalog is a waste of time.

[Glock27]

It assumes that other life on other planets would be humanlike and thus need a similar environment.

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.

Re:Why do it?

[mysticgoat]

I find the fascination with Extra-Terrestrials quite interesting. Is there some need for us to seek for someone outside of ourselves? Has the search for God been replaced by the search for ET? Are we looking for a God replacement?

I can only answer for myself, of course:

1. Not a need in my case, but a desire that is stronger than the urge to purchase lottery tickets. See below.
2. No, I continue to seek the gods as well as having an interest in seeking ET sentience. Obtaining a positive answer for one would probably have an impact on how I do the other, but at this point I do not see them as related endeavors. Certainly not as mutually exclusive pursuits.
3. No, I wouldn't regard any other form of carbon/water based life as being a god substitute. Nor do I regard SETI's activities to be some kind of replacement for spiritual explorations.

The reason I bring this up is that there is a very remote chance that an ET signal will ever be found and an even more remote chance that we will be able to communicate with them (impossible in the foreseeable future). So why spend money when the odds are so very low? What is this fascination?

Agreed: the chances of SETI's success are very small. And the chance of finding that signal would be even more remote if nobody looks for it.

As you suggest, the meat of the issue is a budgetary problem. If SETI is successful, reception of that first message would have as much impact on science, art, and religion as the Copernican revolution. It would be like winning the lottery, but bigger. So how cheap does the lottery ticket need to be before it makes sense to buy one every month? I think SETI is cheap enough to budget for.

But SETI is unlike the lottery in one important way: if signals are not found in a reasonable length of time, that will tell me something useful. For instance, if the NASA Manned Mars Mission Proposal includes US$1 billion to develop a death ray to deal with inimical aliens, I would use SETI's negative findings to argue against such a pork barrel.