Date: January 25, 2010
Title: 6th Anniversary of Opportunity’s Arrival on Mars
Podcaster: Ken Brandt
Links: Mars Rover website: marsrovers.jpl.nasa.gov
Description: Do you remember where you were 6 years ago-January 25th, 2004? On that evening, the second of two Mars rovers was making its descent into the cold, thin Martian air.
Bio: Ken is an astronomy educator, planetarium director, and an ardent fan of space exploration and exploration. Ken loves teaching, and some of his finest hours are spent with students, be they third graders or college seniors. Ken also reminds us that we are one planet, and we all live under the same night sky.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Craig Clark.
Transcript:
MER Opportunity 6th Anniversary Podcast
Do you remember where you were 6 years ago-January 25th, 2004? On that evening, the second of two Mars rovers was making its descent into the cold, thin Martian air. This was the first probe whose landing site was dictated by surface mineral type. The mineral is hematite, an Iron and sulfur mineral that normally forms in hot water here on Earth.
Since the primary mission of the rovers was to uncover direct evidence of liquid water in Mars’ past, the selection of this landing site, a place called ‘terra meridiani’, was a natural choice. It helped too that this site was near the Martian equator, so the solar panels that power Opportunity would have good Sun to work with. It was also flat, but no one had any idea just HOW flat it would really be! Opportunity landed successfully, and took its first of more than 130.000 images of Mars. Those first black and white images showed that Opportunity has landed in a crater roughly the size of the kickoff circle on a Soccer (football) field! Not only that, but at one end of this small crater there was a 2-foot tall cliff of layered rocks! This was the first time any of the landers had seen sediments on Mars. The next discovery Opportunity made was just as splendid.
There were millions of small, ball-shaped objects littering the ground around Opportunity. This, it turns out, is the hematite. The mission science team nicknamed these small spheres blueberries. Next, there were crossbeds in the rocks, and ripple marks, indicating a shoreline on the edge of a body of liquid water. The evidence for liquid water was now confirmed. Mars was warmer and wetter in its distant past!
Over the last 6 years, Opportunity has travelled over 11.75 miles, or almost 19 Kilometers! She has driven into and out of 3 craters, and is meandering across the plains of Meridiani to a fourth-Endeavor crater. Along the way, she documents continuing evidence of that liquid water past in this part of Mars-and the blueberries remain everywhere around her wheels! Layered sedimentary rocks present themselves wherever she goes, and she has also found 3 meteorites, and several chunks of Martian crust blasted from deep within Mars by these impacts.
Opportunity carries aboard her a suite of geological instruments, including the equivalent of a rock hammer (a dremmel-like instrument called the rock abrasion tool, or RAT), 3 spectrometers, and a microscope. The next Mars rover, Curiosity, will carry on board more sophisticated instruments for detecting life and other chemical processes on Mars.
For me, though, the best part of this mission is the daily updates! Every day (more than 2,200 on Mars, and counting!) Opportunity sends back pictures of places we’ve never seen up close, places she has driven to during the previous day. If you go to the Mars rover web site marsrovers.jpl.nasa.gov, and click on ‘Opportunity raw images’ you can see the entire mission in image form! The new images are labeled accordingly, so every day you can get the update without having to wait for the official interpretations, etc.
End of podcast:
365 Days of Astronomy
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The link below leads to an analysis of putative Martian shorelines showing that the lines are most likely produced by water or ice oceans:
http://mysite.verizon.net/rickmsmith/MarsOceanProject.html
The analysis uses an accurate three-dimensional model of Mars
(using MOLA data) to analyze the shorelines reported by Clifford and
Parker (2001) and shows that the lines are, in fact, equipotentials – like a bathtub ring – in the northern basins that could have held water.
Regardless of the arguments against the former existence of large bodies of water on Mars, the coincidence of the putative shorelines and the perimeters of the basins must be considered.
I just wanted to say thank you for this episode. Today (March 21), I’d had a bad day and was in a funk, and I decided to lift my spirits by listening to some 365DoA episodes, because it was a familiar show that could be depended upon to be sane, logical, and facts-based. I happened to start out with your episode. It worked. I felt better. Thank you for contributing.