Jill Tarter on SETI’s 50-year search for extraterrestrial life

SETI stands for Search for Extra-Terrestrial Intelligence. The director of SETI’s research spoke with EarthSky.

Jill Tarter: People have been wondering whether there’s life elsewhere for millennia, and what we used to do is ask the priests and the philosophers what we should be believe.

Astronomer Jill Tarter is director of the Center for SETI Research. SETI stands for Search for Extra-Terrestrial Intelligence.

Jill Tarter: What was so cool is that in the middle of the 20th century, we got some new tools –radio telescopes – that would allow us to do an experiment to try to answer the question scientifically.

Tarter explained that the organization started its search for extraterrestrial life in the 1960’s, using one 85-foot telescope to monitor radio signals from two stars.

Jill Tarter: Today we’re looking at many stars at once, with hundreds of millions of spectral channels. Our tools for searching are getting better, and faster, exponentially.

2010 will mark SETI’s 50 -year anniversary. Tarter said that, as far as scientists know, no SETI device has ever received a signal from extraterrestrial intelligence. But Tarter believes that SETI can still change life here on Earth.

Jill Tarter: Getting people actively involved in doing SETI gives us an opportunity to get them to change their perspective, to actually look at themselves within a vast cosmos. And that, if you really take it seriously, has the effect of trivializing the differences among people, and that’s got to be good.

Tarter said that she doesn’t believe seeking signals from outer space is a shot in the dark.

Jill Tarter: But it certainly is like looking for a needle in a really large haystack. Our haystack’s perhaps nine dimensions if you consider three spatial dimensions and the dimension of time and two polarizations and frequency all of those. So, a lot of different places where a signal could reside. Which means that it may take us a very long time to search through the haystack.

She said that, if we get a message, it might prove a real puzzle for scientists.

Jill Tarter: If we get a message and it has information content, how are we going to interpret it, how can we decode it? You can hope, it’s a deliberate message, someone will have gone to the trouble of making it anti-cryptographic. That is, easy to understand. But what’s easy for them to understand may not be easy for us.

She said SETI sent out its own message in the 1970’s to a globular cluster about 25,000 light years away from the Arecibo radio telescope.

Jill Tarter: It was an attempt in two dimensions to give a counting lesson, to talk about our carbon chemistry and DNA, and how many people are on the planet, and how big we are. Because one of the things about a radio message is that you automatically have a ruler. You can say, “We’re three wavelengths tall.”

Tarter said that, in some ways, humans aren’t fully equipped to properly monitor and broadcast signals to space because the effort would have to be constant over thousand or ten thousand years period. We don’t have the equipment or capability, as yet. But that has a flip side, she said. If we ever get a message, we’ve discovered the archaeology of the future.

Jill Tarter: Phil Morrison of MIT had this lovely way of characterizing SETI. He said it is, in fact, the archaeology of the future. Any signal we receive is going to tell us about their past. Because it only could travel at the speed of light to get here. And if we detect a signal, then in fact we know it’s possible for technologies to last for a long time. Because no two civilizations will ever co-exist in time to find one another.

Tarter said that polls show that up to 50% of Americans believe that we’re not alone in the universe…that’s there’s some form of extraterrestrial life out there. Even without proof.

Beth Lebwohl