JANUARY 18,1996


Two new planets, and the possibility of life on them, is discussed by San Francisco State astronomer Dr. Geoffrey Marcy and Elizabeth Farnsworth.

ELIZABETH FARNSWORTH: Finally tonight, more secrets from space. If it seems we're being bombarded by news from outer space recently, that's because the American Astronomical Society gathering in San Antonio this week is producing some startling findings: First, billions more galaxies than were previously believed, second, new discoveries about the missing mass of the universe; now, new planets and the possibilities of life. That last is our subject tonight, and we're joined from San Antonio by Dr. Geoffrey Marcy, an astronomer at San Francisco State University. Thank you for being with us, Dr. Marcy.

GEOFFREY MARCY, San Francisco State University: (San Antonio) Thank you.

ELIZABETH FARNSWORTH: How did you find these two planets?

GEOFFREY MARCY: Well, we've been looking for planets now for eight and a half years with a totally new technique which employs large telescopes and watching for the wobble of a star due to the gravitational pull of the attendant planets which sadly we can't see directly. They're simply too faint.

ELIZABETH FARNSWORTH: So you were looking for, you were watching these stars. You have, what, a hundred stars you're watching, right?

GEOFFREY MARCY: That's right. A hundred and twenty solar like stars.

ELIZABETH FARNSWORTH: Explain the wobble a little bit.

GEOFFREY MARCY: Our own Sun, for example, sits there quiescently in space, but meanwhile, the nine planets in our own solar system tug on it from all directions as the planets orbit around. This tugging causes our Sun to wobble in space, detectable if you were an alien observing our Sun from the outside, from another star. And we, similarly, can watch other stars and see if they wobble. Then it's a simple matter of using Newton's laws of physics to deduce the properties of the planets that are tugging on those stars.

ELIZABETH FARNSWORTH: So what was your eureka moment?

GEOFFREY MARCY: Well, we had two eureka moments, which is I guess more than we could imagine. We found two planets in the last month, and it's really a matter of analyzing the data we get from telescopes, and suddenly on your computer screen you're done with the analysis. There, we saw the wobble of the two stars, and it was stunning, believe me. We were just amazed.

ELIZABETH FARNSWORTH: Why is this possible now? What technology have you got that you didn't have say two years ago.

GEOFFREY MARCY: Yeah. That's a very good question. A number of new technologies have come to the fore. The Hubble Space Telescope and the big Keck Telescope have taught us a lot about optics, and we've redesigned many of the optical components in our spectrometers and telescopes. In addition, we need the most powerful computers like the SUN Microsystems work stations that we use, and without those, our work wouldn't be possible.

ELIZABETH FARNSWORTH: What, what makes you think there could be water or other life, life-giving, something that would make life possible on these planets?

GEOFFREY MARCY: Well, it's a very straightforward calculation that, in fact, we teach our undergraduates in college, that as you consider planets farther and farther from their host star, they receive less heat from that star, and so the most distant planets are cool, but the planets that are close are hot, and we've found now two planets that are somewhere in-between. One of them in particular has a temperature such that water would be in liquid form, rather than ice or vapor.

ELIZABETH FARNSWORTH: Now, these are not earth-like planets. As I understand it, these are gaseous planets, or you believe they're gaseous planets. Why should anybody care about this? What's significant about it?

GEOFFREY MARCY: Well, I think there are a couple of things that are significant. It's true that these planets we've found are probably kin of our own Jupiter and, therefore, are mostly gaseous, with hydrogen, helium, methane, ammonia, not really much like our Earth, but what's exciting, of course, is that these planets are residing in just the position that our own terrestrial planets, Mars and Earth and Venus, reside, and it gives us tremendous hope that we will someday find Earth- like planets at those distances from other host stars.

ELIZABETH FARNSWORTH: And what about some kind of life on these planets? I mean, that's what's implied, that there might be some kind of life on these planets too.

GEOFFREY MARCY: Well, it's, it's a realm of biochemistry that is going to flourish now, I think, for researchers in those fields, the question being: Could life arise perhaps not on a hard surface like happened on the Earth but, instead, in these gaseous atmospheres at lukewarm temperatures.

ELIZABETH FARNSWORTH: Some reports said that astronomers at the meeting in San Antonio were saying this is the beginning of a whole new era in astronomy. Do you think that's so?

GEOFFREY MARCY: Well, it's even bigger than that. It's certainly an era in astronomy in the sense that we will bring in other sub-fields of chemistry, biology, meteorology, geology. But even more than that, NASA is now going to begin to contribute to this effort with a major new program of space- born telescopes, a daughter of Hubble Space Telescope first, and then other deployable telescopes which NASA hopes will allow us to detect small Earth-like planets around other stars.

ELIZABETH FARNSWORTH: We can't see pictures of these planets now. Might we in the future?

GEOFFREY MARCY: Uh, we can't see the planets at all, and the hope is with NASA's help we will be able to do so and maybe even take a picture of one someday, or our grandchildren will be around someday to see pictures of other Earth-like planets.

ELIZABETH FARNSWORTH: What is the next step in the research that you plan to do with your associate?

GEOFFREY MARCY: Well, it's very exciting. Our technology, indeed, continues to improve, and we now have the capability of detecting not just Jupiter-like planets, as you mentioned we've done, but now begin to find Saturns around other stars, maybe Neptune-like or Uranus-like planets, and push down to lower masses edging toward our own Earth-like planet.

ELIZABETH FARNSWORTH: So in the next--you'll still be watching these hundred stars, right, and you'll--

GEOFFREY MARCY: That's right.

ELIZABETH FARNSWORTH: --And you'll still be looking for this doppler effect, the wiggle movement?

GEOFFREY MARCY: The wiggle, right.

ELIZABETH FARNSWORTH: And then what specifically will you be doing?

GEOFFREY MARCY: Well, we are going to go back to the telescope in March. We're going to gather more data, and we have, as you say, a hundred and twenty stars that we need to continue watching with the new technology. And the real question here is: How many stars have planets? And are any of those planets like our own set of nine planets in our solar system? Will we begin to find in a sense reflections of our own solar system as seen in the stars at night?

ELIZABETH FARNSWORTH: Well, Geoffrey Marcy, thank you for being with us.

GEOFFREY MARCY: My pleasure.

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