Martian terraces
Glacier country on Mars
Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 17, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists have labeled “Dipping layers against mound in Deuteronilus Mensae.”
Deuteronilus is the westernmost mensae region in the 2,000-mile-long strip of heavy glaciers found in the northern mid-latitudes that I dub glacier country. This photo, the location of which is marked by the white cross on the overview map above, is another example, though somewhat strange and puzzling. Normally the layers will dip away from the high point. Here, the layers dip towards the mound. I can think of only one explanation, that of prevailing winds causing the erosion in this unusual manner, but I also find that explanation very unsatisfactory.
The layers themselves illustrate the cycles that have shaped Martian geology, caused by the wide swings in the planet’s rotational tilt, from 11 to 60 degrees. When that tilt is high, the poles are warmer than the mid-latitudes, and water ice migrates from the poles towards the equator. When the tilt is low, the mid-latitudes are warmer, and the water ice heads back towards the poles. Thus, the many many layers the orbiters and rovers are now finding everywhere on Mars.
Right now scientists think, because Mars’ tilt is in the middle of these swings at 25 degrees, the planet is in equilibrium, with the water at the poles and mid-latitudes essentially going no where. This conclusion however is not yet confirmed.
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. from any other book seller, or direct from my ebook publisher, ebookit.
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
Glacier country on Mars
Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 17, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists have labeled “Dipping layers against mound in Deuteronilus Mensae.”
Deuteronilus is the westernmost mensae region in the 2,000-mile-long strip of heavy glaciers found in the northern mid-latitudes that I dub glacier country. This photo, the location of which is marked by the white cross on the overview map above, is another example, though somewhat strange and puzzling. Normally the layers will dip away from the high point. Here, the layers dip towards the mound. I can think of only one explanation, that of prevailing winds causing the erosion in this unusual manner, but I also find that explanation very unsatisfactory.
The layers themselves illustrate the cycles that have shaped Martian geology, caused by the wide swings in the planet’s rotational tilt, from 11 to 60 degrees. When that tilt is high, the poles are warmer than the mid-latitudes, and water ice migrates from the poles towards the equator. When the tilt is low, the mid-latitudes are warmer, and the water ice heads back towards the poles. Thus, the many many layers the orbiters and rovers are now finding everywhere on Mars.
Right now scientists think, because Mars’ tilt is in the middle of these swings at 25 degrees, the planet is in equilibrium, with the water at the poles and mid-latitudes essentially going no where. This conclusion however is not yet confirmed.
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. from any other book seller, or direct from my ebook publisher, ebookit. 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
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