Strange fernlike ridges on Mars
Cool image time! The two images on the right, cropped, rotated, and reduced in resolution to post here, were both taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). To see the full resolution version of each, go to the 2009 and 2018 releases.
The 2009 release was a captioned release, whereby scientist Alfred McEwen of the science team provided his explanation of these strange features.
The dark branched features in the floor of Antoniadi Crater look like giant ferns, or fern casts. However, these ferns would be several miles in size and are composed of rough rocky materials.
A more likely hypothesis is that this represents a channel network that now stands in inverted relief. The channels may have been lined or filled by indurated materials, making the channel fill more resistant to erosion by the wind than surrounding materials. After probably billions of years of wind erosion the resistant channels are now relatively high-standing. The material between the branched ridges has a fracture pattern and color similar to deposits elsewhere on Mars that are known to be rich in hydrated minerals such as clays.
These strange fernlike features do not appear to be very common on Mars. In fact, I suspect that while Mars does have many inverted channels like this, the fernlike nature of these particular channels is unique on Mars. They are located on the floor of Antoniadi Crater, a large 240-mile-wide very ancient and eroded crater located in the Martian southern highlands but near the edge down to the northern lowlands.
In seeing the new 2018 image, I was immediately compelled to place it side by side with 2009 image to see if anything had changed in the ensuring near-decade. There are color differences, but I suspect these are mostly caused by different lighting conditions or post-processing differences. Still, the dark center to the crater in the upper left of both images suggests a change in the dust dunes there, with the possibility that some of the dust has been blown from the crater over time. Also, you can see two horizontal tracks cutting across the center of the 2018 image, which I would guess are dust devil tracks, with one more pronounced.
I can imagine some planetary geologists have spent the last few months, since the second image was taken, pouring over both photographs, and have might even located other interesting changes. And if they find no significant changes, that in itself is revealing, as it gives us a sense of the pace at which the Martian surfaces evolves.
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 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
Cool image time! The two images on the right, cropped, rotated, and reduced in resolution to post here, were both taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). To see the full resolution version of each, go to the 2009 and 2018 releases.
The 2009 release was a captioned release, whereby scientist Alfred McEwen of the science team provided his explanation of these strange features.
The dark branched features in the floor of Antoniadi Crater look like giant ferns, or fern casts. However, these ferns would be several miles in size and are composed of rough rocky materials.
A more likely hypothesis is that this represents a channel network that now stands in inverted relief. The channels may have been lined or filled by indurated materials, making the channel fill more resistant to erosion by the wind than surrounding materials. After probably billions of years of wind erosion the resistant channels are now relatively high-standing. The material between the branched ridges has a fracture pattern and color similar to deposits elsewhere on Mars that are known to be rich in hydrated minerals such as clays.
These strange fernlike features do not appear to be very common on Mars. In fact, I suspect that while Mars does have many inverted channels like this, the fernlike nature of these particular channels is unique on Mars. They are located on the floor of Antoniadi Crater, a large 240-mile-wide very ancient and eroded crater located in the Martian southern highlands but near the edge down to the northern lowlands.
In seeing the new 2018 image, I was immediately compelled to place it side by side with 2009 image to see if anything had changed in the ensuring near-decade. There are color differences, but I suspect these are mostly caused by different lighting conditions or post-processing differences. Still, the dark center to the crater in the upper left of both images suggests a change in the dust dunes there, with the possibility that some of the dust has been blown from the crater over time. Also, you can see two horizontal tracks cutting across the center of the 2018 image, which I would guess are dust devil tracks, with one more pronounced.
I can imagine some planetary geologists have spent the last few months, since the second image was taken, pouring over both photographs, and have might even located other interesting changes. And if they find no significant changes, that in itself is revealing, as it gives us a sense of the pace at which the Martian surfaces evolves.
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 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
Poring
What a decorative feature. I’m reminded of ice that sometimes forms inside the glass of our porch windows this time of year.
I was going to comment that we had this print on wallpaper at some time.
It didn’t seem like an other worldly room at the time.