Secondary impacts in water ice on Mars
Click for full resolution image.
Cool image time! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) released a beautiful captioned image of a secondary impact of an object into the icy plains of Utopia Planitia, the northern lowlands northeast of where the rover Perseverance will land in 2021. The image to the right, cropped and reduced to post here, shows one of several secondary craters in the full image. As planetary scientist Alfred McEwen explains in the caption,
One interpretation [for the crater’s unusual appearance] is that the impact crater exposed nearly pure water ice, which then sublimated away where exposed by the slopes of the crater, expanding the crater’s diameter and producing a scalloped appearance. The small polygons are another indicator of shallow ice.
Note the dunes at the bottom of the crater. This has become a trap of wind-blown sand and dust. Note also how this secondary impact gives us a rough idea of the thickness of this ice, based on the area sublimated away.
There is a lot of relatively accessible ice in those northern lowlands, which is why SpaceX likes them for its possible landing site for Starship. That candidate site is in Arcadia Planitia, on the other side of Mars, but it is still in these same northern lowlands, where scientists have found lots of evidence of buried ice.
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Click for full resolution image.
Cool image time! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) released a beautiful captioned image of a secondary impact of an object into the icy plains of Utopia Planitia, the northern lowlands northeast of where the rover Perseverance will land in 2021. The image to the right, cropped and reduced to post here, shows one of several secondary craters in the full image. As planetary scientist Alfred McEwen explains in the caption,
One interpretation [for the crater’s unusual appearance] is that the impact crater exposed nearly pure water ice, which then sublimated away where exposed by the slopes of the crater, expanding the crater’s diameter and producing a scalloped appearance. The small polygons are another indicator of shallow ice.
Note the dunes at the bottom of the crater. This has become a trap of wind-blown sand and dust. Note also how this secondary impact gives us a rough idea of the thickness of this ice, based on the area sublimated away.
There is a lot of relatively accessible ice in those northern lowlands, which is why SpaceX likes them for its possible landing site for Starship. That candidate site is in Arcadia Planitia, on the other side of Mars, but it is still in these same northern lowlands, where scientists have found lots of evidence of buried ice.
Readers!
My annual February birthday fund-raising drive for Behind the Black is now over. Thank you to everyone who donated or subscribed. While not a record-setter, the donations were more than sufficient and slightly above average.
As I have said many times before, I can’t express what it means to me to get such support, especially as no one is required to pay anything to read my work. Thank you all again!
For those readers who like my work here at Behind the Black and haven't contributed so far, please consider donating or subscribing. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Every one of those 2020 conclusions has turned out right.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
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