Category Archives: Mars

jet Propulsion Laboratory, Mars, mars climate, Mars Reconnaissance Orbiter, NASA

Mars Missing Carbon Dioxide May Not Be Missing

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It Might Just Be Buried

This image shows the context for orbital observations of exposed rocks that had been buried an estimated 5 kilometers (3 miles) deep on Mars. It covers an area about 560 kilometers (350 miles) across, dominated by the Huygens crater, which is about the size of Wisconsin. The impact that excavated Huygens lifted material from far underground and piled some of it in the crater's rim. At about the 10 o'clock position around the rim of Huygens lies an unnamed crater about 35 kilometers (22 miles) in diameter that has punched into the uplifted rim material and exposed rocks containing carbonate minerals. The minerals were identified by observations with the Compact Reconnaissance Imaging Spectrometer for Mars on NASA's Mars Reconnaissance Orbiter. North is toward the top of this image, which is centered at 14 degrees south latitude, 304.4 degrees west longitude. The image combines topographical information from the Mars Orbiter Laser Altimeter instrument on NASA's Mars Global Surveyor with daytime infrared imaging by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter. Image credit: NASA/JPL-Caltech/Arizona State Univ. Click to enlarge.

I am a long-time Mars junkie. When I was growing up, I used to play at exploring Mars, and I probably expected to be living on the Red Planet some day.  Childhood dreams are like that — and the reality they lead to is a far different place.

For example, my “play” Mars looked a lot like Earth. Oh, the sky was red (I figured it had to have a red atmosphere).  It had red trees and red monsters and red food.  But, it never occurred to me that I wouldn’t be able to stand on its surface and breathe the air.  That’s a lesson I had to wait to learn when I grew up and studied the results of ongoing Mars missions. That was when I found out that Mars doesn’t have air like we do here on Earth. it’s got a carbon dioxide (CO2) atmosphere. A thin one, at that.  But, scientists suspect that the Red Planet used to have MORE atmosphere.

One of the recurring questions about Mars is the location of all its carbon dioxide. The Red Planet has a cold, thin, carbon-dioxide-rich atmosphere. Liquid water quicky boils away in that environment.

CO2 can get squirreled away in rocks, so-called carbonate minerals or carbonate layers. If they’re underground (under the surface), then that material isn’t easily found — unless you can dig it up and study it.

Essentially, that’s what planetary scientists using the Mars Reconnaissance Orbiter (MRO) have done. Oh, they haven’t used the orbiter to dig underground. They used it as it orbited above the surface to study rocks that have been dug up for us — by cratering events. Such an event was reported on at a meeting of planetary scientists this week.

The target studied was in Huygens crater, a basin 467 kilometers (290 miles) in diameter in the southern highlands of Mar. There are actually two cratering events in the area.  When Huygens was dug out by an incoming impactor, that action hoisted material from far underground. Then, the rim of Huygens, containing the earlier lifted material, was drilled into by a smaller, unnamed cratering event.

The occurrence of carbonate in association with the largest impact features suggests that it was buried by a few kilometers (or miles) of younger rocks, possibly including volcanic flows and fragmented material ejected from other, nearby impacts.

So, how does an impact dredge up rocks that show us what Mars was like in the past? When a meteor blasts into the surface of Mars (or any surface), it sends material flying away from the impact zone. That uncovers buried rocks. The MRO has an instrument that can study the chemical makeup of those rocks that have been uncovered.

At several places on Mars where cratering has exposed material from depths of about five kilometers (three miles) or more beneath the surface, MRO’s instrument has found evidence of carbonate minerals. This isn’t the first time carbonates have been found, but the finding does seem to confirm the speculated-on whereabouts of the missing Mars carbon.  And, if there are deeply buried carbonate layers are widespread on Mars, that would go a  long ways toward explaining what happened to the early Martian atmosphere, whihc was likely a much thicker carbon dioxide layer than we see on the Red Planet today.  In essence, the carbon that goes into formation of carbonate minerals can come from atmospheric carbon dioxide.

A dramatic change in atmospheric density remains one of the most intriguing possibilities about early Mars. Increasing evidence for liquid water on the surface of ancient Mars for extended periods continues to suggest that the atmosphere used to be much thicker.

The Technical Low-Down

The observations for this study were made using the high-resolution mode of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter show spectral characteristics of calcium or iron carbonate at this site. Detections of clay minerals in lower-resolution mapping mode by CRISM had prompted closer examination with the spectrometer, and the carbonates are found near the clay minerals. Both types of minerals typically form in wet environments, which raises a number of questions about Mars’s early atmosphere and interactions of that atmosphere with the surface.

astronomy, friends of the observatory, gift ideas, griffith observatory, Mars, mars exploration rovers

Space for the Holidays

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Giving the Gift of Astronomy

We went shopping the other day. This is the season for prolongued bouts of buying stuff for our loved ones, friends, bosses, whoevers, and of course, you can find all kinds of gew-gaws out there to give.  Mr. Spacewriter and I were looking for specific objects,  and we did find a few things, but not quite what we were looking for.  Still, it was interesting to browse the aisles of some stores and see what the marketing types thought we should be giving to others: electronic book readers, the latest phones, computers, perfumes, clothes, and even household things like vacuum cleaners. Not knocking those things — I’m sure that somebody’s baby out there wants one of those objects and whoever gets it for them will be a hero, at least for the holidays.

If you’ve been out there bulling your way through the maddening crowds and haven’t found something that quite matches for someone you want to impress/love/woo/etc., why not consider giving an astronomy- or space-related gift?  I’ve got a few suggestions here that might help you out of what could be a tough gift bind. (Or, maybe you want to treat yourself to something spacey…)

First, I am a member of Friends of the Observatory, the support group for Griffith Observatory in Los Angeles, California. You can be, too, and you don’t even have to live there.  I don’t live in SoCal, but I do find myself working/visiting/doing business out there throughout the year, and a trip to Griffith is always one of my stops.  FOTO, as it’s lovingly called, does a lot of good things for the observatory — which is one of the most popular public observatories in the world. Among other things, FOTO gathers the funds to bring students from the Los Angeles Unified School District on fifth-grade school field trips. This is a trip that, without funding, many school kids would never get to experience, and I support anything that brings the science of astronomy to kids in a meaningful way.  You can join for as little as $45.00, which gets you a number of great benefits, including a one-year subscription to the world-famous Griffith Observer. I’ve been supporting Griffith for a number of years now through FOTO, and even though I don’t live there, I find it to be a wonderfully rewarding investment.  So might you. Check out FOTO at the link above. (For the record, I also wrote all of Griffith Observatory’s exhibits — so, if you go there, check out the words on the walls… I guarantee, you’ll learn some astronomy!)

I’m also a member of the Astronomical Society of the Pacific, an astronomical organization that works to increase the understanding and appreciation of astronomy by everyone, using scientists, educators, enthusiasts, and the public to advance science and science literacy. I have been working with this group for a couple of years now on a project called “Astronomy Behind the Headlines” — a series of podcasts that’ll bring you in contact with scientists at the cutting edge of astronomy. ASP is a godsend for teachers and outreach specialists, as well as folks who are just plain curious about the universe.  GO check out their Web page and see if a membership or donation to ASP is a fit with your gifting goals.

As many of my long-time readers know, I love books. I’ve written a couple about astronomy and space science, and I like to read astro books, too.  Just in time for the holidays a couple of really neat ones have landed on my desk and you might like them, too.

The first is called “Postcards from Mars” — written by Dr. Jim Bell, astronomer and planetary scientist at Cornell University in New York, and published  by Plume  Books. Jim was in charge of the photography teams on the Spirit and Opportunity missions that are still sending back images from Mars. For this book, which is gorgeous, he spent hundreds of hours selecting images from the rovers, cropping and processing them, and aseembling them into a book that tells the tale of the rovers from launch to the continuous stream of image deliveries they’ve made during their mission lifetimes.  I really enjoyed this book — twice. First, I simply leafed through it, admiring all the wonderful images. Then, I read through it, appreciating the story of two missions as told by one of the mission scientists who put these images in front of us.  It’s really a great find and if you have a Mars lover on your gift list (or if you are one), then this is a great find. I know I loved looking through it — but then again, I’m an old Mars fanatic from way back.  You can’t beat postcards from another planet as a way to impress your giftee!

The other book that found its way onto my reading list is called Sizing up the Universe: a New View of the Cosmos and published by National Geographic.  Anyone who studies astronomy is instantly engulfed by the scales of objects we explore.  From the sizes of planets to the limits of the observable universe, the scale of the cosmos can sometimes be more than we can easily comprehend. That’s where this book comes in — it seeks to help you understand just how big things are and how far away they are — in terms that won’t completely boggle your mind. It uses scaled maps and comparisons of objects at different scales, by way of gorgeous illustrations, to help readers understand size comparisons in the universe. It presents the vast distances of the cosmos in a very beautiful and graphical way — including an instantly understandable Gott-Juric Map of the Universe in Chapter 4 that has been reprinted as a foldout map.  The authors, Princeton professors J. Richard Gott and Robert J. Vanderbei, write in a very clear and approachable way and their explanations of distances and sizes by analogy are very good.  For example, there’s a set of beautiful images in a section called “Exoplanets Compared” that shows some of the known exoplanets overlying their parent stars, and with solar system planets overlaid in comparison. You instantly “get” the size of these worlds and their stars.  The book is a treasury of these kinds of comparisons.  There’s a  lot more, which makes this book a great gift for that person in your life who is curious about what’s “out there,” how big it is, and how far away it is.

In closing, I have to admit that I do really enjoy reading actual books.  I’ve been pondering getting a Kindle or a  Sony reader or something, and I actually played with one the other day. But, you know… it just doesn’t hold a candle (or Kindle) to turning the pages and basking in the loveliness of a book on a lazy afternoon… and, I wonder just how well an astronomy book like these two would work out on the readers.  And, of course, NO reader is going to give you the same experience as visiting a place like Griffith or belonging to a group like ASP… they’re all worthy experiences, requiring different applications of your personal attention.

Happy Space Gifting!