Date: July 8, 2011
Title: Prize Winning Planetary Research
Podcaster: Bob Hirshon, AAAS
Organization: American Association for the Advancement of Science (AAAS)
Description: Science Update host Bob Hirshon speaks with planetary geologist Scott Murchie of the Johns Hopkins Applied Physics Laboratory. Murchie was recently awarded the NASA Distinguished Public Service Award, NASA’s highest honor for non-government personnel. Murchie discusses his work on imaging systems for the Mars Reconnaissance Orbiter and the MESSENGER Mission to Planet Mercury.
Bio: Bob Hirshon is Senior Project Director at the American Association for the Advancement of Science (AAAS) and host of the daily radio show and podcast Science Update. Now in its 24th year, Science Update is heard on over 300 commercial stations nationwide. Hirshon also heads up Kinetic City, including the Peabody Award winning children’s radio drama, McGraw-Hill book series and Codie Award winning website and education program. He oversees the Science NetLinks project for K-12 science teachers, part of the Verizon Foundation Thinkfinity partnership. Hirshon is a Computerworld/ Smithsonian Hero for a New Millennium laureate.
Sponsor: The Education and Outreach team for the MESSENGER mission to planet Mercury. Follow the mission as the spacecraft helps to unlock the secrets of the inner solar system at www.messenger-education.org
Transcript:
Welcome to the 365 Days of Astronomy Podcast. I’m Bob Hirshon, host of the AAAS radio show and podcast Science Update.
Before I get into today’s topic, I did want to touch on a past podcast. Back in January, in a sleep-deprived stupor, I challenged listeners to write original songs about the solar system, send them to me, and I’d use them as the basis for a future podcast. Well, only one person sent a song: Adrian Morgan, of Adelaide, South Australia. I didn’t want to do an entire podcast just on Adrian’s song, worthy though it is, so he is doing one of his own. It’s called Flock of Worlds and you can hear it right here on August 14th. So Adrian, good luck, have fun and we’ll look forward to it.
Now, a couple of days ago I got a press release stating that Scott Murchie, a planetary geologist at the Johns Hopkins Applied Physics Lab, was being awarded the NASA Distinguished Public Service Award. This is a huge deal—it’s NASA’s highest award for non-government workers. Now, Scott works on the MESSENGER Mission to Planet Mercury, which is now in orbit, and the Mars Reconnaissance Orbiter, also now in orbit. So I asked Scott if he’d be on the show to discuss his work and he said yes.
NASA is giving him the Award in recognition of his leadership of the CRISM, or Compact Reconnaissance Imaging Spectrometer for Mars investigation. He explains that the device takes high-resolution images of the Martian surface.
Murchie
But instead of just taking an image in a few colors, it takes it in over 500 colors at the same time. So for every pixel in your image, you have a spectrum of the material in the surface, and you can use that to infer the composition of material at that location on the surface of Mars.
Hirshon:
CRISM was instrumental in the discovery of water on Mars—which Science magazine selected as one of the ten insights of the decade. Murchie says that now they are focused on learning more about the Martian water.
Murchie:
And so we’re looking at the mineralogy trying to understand where did water persist long enough on the surface that it might have presented a habitat for life, what was the chemistry of the water like, as evidenced by the minerals that it left behind, and where were these wet environments strewn throughout Mars’ history.
Hirshon:
The environments are ancient—he estimates between three and four billion years old. But CRISM data allows the science team to reconstruct the conditions that most likely led to them.
Murchie:
We’ve found evidence for probably a dozen different kinds of wet environments on ancient Mars. By a dozen different kinds of environments, I mean places like a salt lake or groundwater that has sort of a distinct recurring set of minerals and landforms that go with it. So the short list of things that we’ve seen are deltas of ancient lakes. We’ve seen deposits in ancient salt lakes. We’ve seen layers of different kinds of clay minerals that might be telling us something about a past weathering environment on Mars. We see evidence of hot springs where silica was deposited on mounds at the base of volcanoes. And about a half dozen other really distinct kinds of places like that, each one with a different temperature, acidity, longevity associated with it.
Hirshon:
The longevity is key, since the main reason the team is so interested in water is because it’s the key to the formation of life.
Murchie:
Some of these environments could have been very transient and that’s one of the most important questions that Mars exploration is looking at right now is were wet environments like this long-lasting enough to give life a chance to have gotten started.
Hirshon:
He says the NASA Award recognizes how CRISM has illuminated Mars’s ancient history and helped guide future missions.
Murchie:
MRO and CRISM in particular, were recognized with a distinguished service medal because we’ve made a pretty big contribution to understanding past Mars, because what we have helped to do is add a new kind of information to understanding the geology of mars, which is composition down at the scale of a few tens of meters. And that has been so important to understanding what the environment was like on early Mars that, for example, it’s been a major factor in deciding where will the Curiosity rover land on Mars, what site will it go to, and we’re now looking at different sites that could be targeted for future sample return.
Hirshon:
Murchie also works on the MESSENGER Mission to Planet Mercury, particularly the imaging system on the spacecraft. Just as with MRO, the MESSENGER team is studying the planet’s surface to gain insights into the processes that formed the planet’s crust. But instead of water, they are focusing on volcanism and impact cratering.
Murchie:
Another interesting thing is that Mercury and Mars are kind of the bookends of the terrestrial planets, because they’re kind of similar in size and gravity, Mars is the outermost terrestrial planet, Mercury is the innermost one. And one of the things that MESSENGER seeks to understand is what was the role of Mercury’s environment very close to the sun in making it very different from the other terrestrial planets.
Hirshon:
And while water didn’t play a role in eroding the surface of Mercury, it may occur on the planet, despite its proximity to the sun.
Murchie:
Even now, in the very cold polar regions, in the permanently shadowed interiors of some of the polar craters, there are deposits which are very reflective of radar that look like they could potentially be water ice. And that’s one of the questions that MESSENGER is investigating, trying to confirm that those are indeed water ice and if they’re not water ice, what are they?
Hirshon:
Murchie says that the exciting thing about both missions is that the data they are now returning are not only leading to new discoveries, but to new questions the scientists never could have imagined—questions they’ll try to answer in the next phases of the missions.
Murchie:
MESSENGER will finish its prime mission in 2012 and we have a proposal into NASA for a new follow-up set of measurements that builds in the questions that we didn’t even know to ask before MESSENGER first saw Mercury. We hope to be doing that science. With CRISM, we’ll be continuing to build on the measurements that we took since we’ve been in orbit. For instance, there we also have questions that we didn’t even know to ask when we first started about some of these different wet environments, understanding where and when they formed. One of the big questions in Mars geology has been were there carbonate rocks formed that might have trapped an ancient atmosphere. Well we found the carbonate rocks and now mapping them out and understanding where they occur and what different kinds of carbonates there are on the planet is an emerging area of science.
Hirshon:
If you’d like to learn more about CRISM or MESSENGER, visit their websites at
That about wraps it up for this time. Thanks for listening. For the 365 Days of Astronomy Podcast, I’m Bob Hirshon.
End of podcast:
365 Days of Astronomy
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