Monday, June 23, 2014

Looking for Hints of Extraterrestrial Life: Q&A with Dr. Adrian Brown of SETI

MRO uses the visible, infrared, and radio ranges of the electromagnetic spectrum to measure water in the atmosphere, on the surface, and below the surface. (Courtesy NASA/JPL-Caltech.)

We find more and more potentially habitable extrasolar planets, what makes us wonder how close are we to finding extraterrestrial life. It could be right next door, on Mars and ancient water could be a major hint. Dr. Adrian Brown, a planetary scientist working at the SETI Institute and NASA Ames Research Center, uses the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to look for those hints. CRISM is an instrument on the NASA’s Mars Reconnaissance Orbiter (MRO), launched in 2005 with the primary objective to search for mineralogic evidence for past water on Mars. CRISM’s observations, in part, confirmed the presence of large amounts of water on Mars in the past, and continue to reveal an extraordinarily complex geologic history of Mars. In an e-mail interview with astrowatch.net, Dr. Adrian Brown talks about search for ET, Mars and CRISM instrument.

Astrowatch.net: Does extraterrestrial life exist?

Dr. Adrian Brown: Almost certainly. Giving ET one chance per star, there are 300 billion chances in this galaxy alone, with 100 billion more galaxies makes for good odds.

Astrowatch.net: Was Mars once habitated?

Brown: That's the key question we could answer if we sent astronauts to Mars. No way of knowing until then, and if it's down where Steve Clifford [planetary scientist at the Lunar and Planetary Institute in Houston, Texas] says there is liquid water (10km) we're going to take a while to find out the answer is surely "no".

Astrowatch.net: Recently at the House hearing, SETI researchers said that we'll find ET life in next 20 years. Can we find life on Mars in that period of time?

Brown: Seth [Dr. Seth Shostak, a senior astronomer at the SETI Institute] was talking probabilities and he has been saying that for more than 20 years. Even I can do that sort of math. As for Mars, if we get there and we're mobile enough to explore a large part (half) of Nili Fossae, we will have a good chance of finding evidence of past life on Mars. So it depends on how hard Elon Musk can push his engineers without a huge revolt. I think they can get there in 20 years, if he doesn't go under a bus.

Astrowatch.net: Can you say for sure that liquid water once flown on Mars and there were rivers and oceans on the Red Planet?

Brown: Yes, for sure liquid water flowed on Mars, but perhaps only briefly did it have the power to make outflow channels. Rivers and oceans are another reason to send astronaut geologists to find out for sure. Of course we've known since 2011 that dark material looking a hell of a lot like liquid water is flowing in the shallow subsurface of Mars, courtesy of HiRISE. Check the video at the bottom of http://abrown.seti.org/about/bio.htm for an interview I did about that.

Astrowatch.net: What celestial body in our Solar System is the best candidate to host life and why?

Brown: Well besides Earth, I think Mars is of course my favorite for finding life ... it still is the place most like our home out there, as Robert Zubrin [Mars Society founder] puts it.

Astrowatch.net: What's the role of the Compact Reconnaissance Imaging Spectrometer for Mars in searching for life on Mars?

Brown: CRISM is designed to look in high resolution at Mars and determine the minerals on the planet's surface. Many minerals will give fingerprint signatures of how hot water and rock have interacted in the past, perhaps when craters impacted the surface, or when volcanic activity took place. These are called hydrothermal systems and they are the best place to look for life, too. I try to find the best indications of that kind of activity.

Astrowatch.net: Could you reveal something about your current research?

Brown: Yes I could, but here is my most recent paper that will help give you an idea of the coolest instrument we could send to Mars in the next decade, at http://arxiv.org/abs/1406.0030.

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