A snakelike Martian ridge
Click for full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on November 22, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labeled a sinuous ridge. Make sure you also look at the full image. The ridge goes on to the south, but then fades way as an almost perfect ramp, only to have another even more wiggly but thinner north-south ridge begin only a few feet to the west.
Sinuous ridges like this are found in many places on Mars. Almost always their origin is thought the result of a former river channel that became a ridge when the surrounding softer material eroded away.
That explanation however does not seem to work for this ridge. It has too many other inexplicable features. For example, note how the peak of the ridge smoothly transitions from sharp to flat-topped. It has a soft appearance that is strengthened by the gap near the top.
It is almost as if this ridge is a kind of elongated sand dune! And guess what: The overview map below gives that explanation some believability.
The white cross marks the location of the ridge, on the edge of the Medusa Fossae Formation, the largest volcanic ash deposit on Mars which is also thought to be the source of much of the red planet’s dust.
Thus, this ridge could very well be volcanic ash, blown into this shape by a variety of local factors (wind, surface features, etc).
Then again, that is a pure uneducated guess. It is also possible that this ridge is a long eroded dike of lava that had in the far past oozed up out of a crack, and has since been shaped by the wind into its curvy shape.
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
Click for full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on November 22, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labeled a sinuous ridge. Make sure you also look at the full image. The ridge goes on to the south, but then fades way as an almost perfect ramp, only to have another even more wiggly but thinner north-south ridge begin only a few feet to the west.
Sinuous ridges like this are found in many places on Mars. Almost always their origin is thought the result of a former river channel that became a ridge when the surrounding softer material eroded away.
That explanation however does not seem to work for this ridge. It has too many other inexplicable features. For example, note how the peak of the ridge smoothly transitions from sharp to flat-topped. It has a soft appearance that is strengthened by the gap near the top.
It is almost as if this ridge is a kind of elongated sand dune! And guess what: The overview map below gives that explanation some believability.
The white cross marks the location of the ridge, on the edge of the Medusa Fossae Formation, the largest volcanic ash deposit on Mars which is also thought to be the source of much of the red planet’s dust.
Thus, this ridge could very well be volcanic ash, blown into this shape by a variety of local factors (wind, surface features, etc).
Then again, that is a pure uneducated guess. It is also possible that this ridge is a long eroded dike of lava that had in the far past oozed up out of a crack, and has since been shaped by the wind into its curvy shape.
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
One would think that it would be possible to distinguish fossil rivers from other ridge origins by observing whether the “river” along its length in effect flows uphill in places in ways that real rivers can’t — providing there’s been little or no geological distortion of the former path of the river (if indeed it is an ex-river) to add such uphill stretches.