The mysteries buried in the Martian south pole ice cap
Click for original image.
Cool image time! The picture to the right, cropped and color-enhanced to post here, was taken on November 3, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The picture is labeled as a “terrain sample,” which means it was likely taken not as part of any specific research project, but to fill a gap in the camera schedule in order to maintain the camera’s proper temperature. In this case the camera team tries to choose interesting features, though sometimes they can’t due to timing.
In this case they were able to target a nice piece of geology, a layered 2,000 foot cliff on the outer edge of the south pole ice cap. The color strip illustrates the possibilities within those layers. I have significantly enhanced the colors to bring out the differences. The orange suggests dust, the aqua-blue water ice, though these colors could also indicate interesting mineralogies.
The white dot on the overview map to the right marks the location of this cliff, about 260 miles from the south pole and inside the vast region scientists have labeled — quite appropriately based on the photo above — the “layered ice/dust deposits”.
The Martian south pole cap as a complex structure. On top is a thin cap of dry ice (indicated by white). Below that is a thick cap of water ice (indicated by blue). Below that is the layered ice/dust cap that extends a great distance beyond.
The layers imply major climate cycles on Mars. Present theories posit these cycles occur because of radical changes in the red planet’s rotational tilt or obliquity, from 11 to 60 degrees, that have taken place numerous times in the last few million years. At this time Mars is tilted 25 degrees, similar to Earth’s 23 degrees. When that tilt is high, however, more than 45 degrees, the planet’s mid-latitudes are colder than the poles, and water ice sublimates away from the poles to fall as snow in the mid-latitudes. During this time the layers of dust at the ice cap likely form.
When that obliquity is low, less than 20 degrees, the mid-latitudes are warmer than the poles and the polar ice cap thickens, producing layers of pure ice, as suggested by the aqua-blue layers.
At least, that’s my guess. It will really take the hands-on analysis of multiple core samples to find out for sure, and that will take colonists on Mars able to do the work.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for original image.
Cool image time! The picture to the right, cropped and color-enhanced to post here, was taken on November 3, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The picture is labeled as a “terrain sample,” which means it was likely taken not as part of any specific research project, but to fill a gap in the camera schedule in order to maintain the camera’s proper temperature. In this case the camera team tries to choose interesting features, though sometimes they can’t due to timing.
In this case they were able to target a nice piece of geology, a layered 2,000 foot cliff on the outer edge of the south pole ice cap. The color strip illustrates the possibilities within those layers. I have significantly enhanced the colors to bring out the differences. The orange suggests dust, the aqua-blue water ice, though these colors could also indicate interesting mineralogies.
The white dot on the overview map to the right marks the location of this cliff, about 260 miles from the south pole and inside the vast region scientists have labeled — quite appropriately based on the photo above — the “layered ice/dust deposits”.
The Martian south pole cap as a complex structure. On top is a thin cap of dry ice (indicated by white). Below that is a thick cap of water ice (indicated by blue). Below that is the layered ice/dust cap that extends a great distance beyond.
The layers imply major climate cycles on Mars. Present theories posit these cycles occur because of radical changes in the red planet’s rotational tilt or obliquity, from 11 to 60 degrees, that have taken place numerous times in the last few million years. At this time Mars is tilted 25 degrees, similar to Earth’s 23 degrees. When that tilt is high, however, more than 45 degrees, the planet’s mid-latitudes are colder than the poles, and water ice sublimates away from the poles to fall as snow in the mid-latitudes. During this time the layers of dust at the ice cap likely form.
When that obliquity is low, less than 20 degrees, the mid-latitudes are warmer than the poles and the polar ice cap thickens, producing layers of pure ice, as suggested by the aqua-blue layers.
At least, that’s my guess. It will really take the hands-on analysis of multiple core samples to find out for sure, and that will take colonists on Mars able to do the work.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News