Weird crater on Moon
Click for full image.
The photo to the right, released today by the science team of Lunar Reconnaissance Orbiter (LRO), takes a overhead view of the unusual crater dubbed Ryder (named after lunar scientist Graham Ryder).
The crater is located on the Moon’s far side, on the edge of the South Pole-Aitken Basin, the Moon’s largest and possibly oldest impact basin. What makes Ryder Crater intriguing is its strange shape, as well as its interior north-south interior ridge.
This crater was featured previously in 2012 in a spectacular oblique image looking east across the crater. Then, the scientists theorized its strange shape was caused by two factors, first that the impact was oblique, and second that it occurred on a steep slope.
Today’s release adds another factor that might explain the interior ridge. The context map below makes that explanation obvious.
Click for full image.
Ryder crater is in the center of the map, on the rim of the much larger crater to its west. As the scientists note at the link,
The steep ridge upon which Ryder formed is the degraded rim of an older crater that is ~70 km [about 44 miles] across, with a vertical drop of over 3000 meters (approximately 10,000 feet) from its rim to its floor. Even this older crater may have been affected by the uneven terrain on which it formed – its eastern rim appears to have formed on a topographic high perhaps related to the [South Pole-Aitken] basin, leaving it well above its western rim. Thus the impactor that formed Ryder crater struck the very highest point of the older crater’s rim, and in this case it is not hard to imagine that the final shape of Ryder crater was strongly affected by its lucky (or unlucky?) encounter with the extra steep slope. The high point of Ryder’s rim is approximately 1500 meters (5000 feet) higher than the low point of its rim!
Impacts tend to increase the density of the materials below, including the rim. When the Ryder impact occurred it was hitting the larger crater’s already squashed rim. The ridge thus appears to be the more resistant dense meterial of that rim, squashed further by the Ryder impact but dense enough already to survive the impact.
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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:
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Click for full image.
The photo to the right, released today by the science team of Lunar Reconnaissance Orbiter (LRO), takes a overhead view of the unusual crater dubbed Ryder (named after lunar scientist Graham Ryder).
The crater is located on the Moon’s far side, on the edge of the South Pole-Aitken Basin, the Moon’s largest and possibly oldest impact basin. What makes Ryder Crater intriguing is its strange shape, as well as its interior north-south interior ridge.
This crater was featured previously in 2012 in a spectacular oblique image looking east across the crater. Then, the scientists theorized its strange shape was caused by two factors, first that the impact was oblique, and second that it occurred on a steep slope.
Today’s release adds another factor that might explain the interior ridge. The context map below makes that explanation obvious.
Click for full image.
Ryder crater is in the center of the map, on the rim of the much larger crater to its west. As the scientists note at the link,
The steep ridge upon which Ryder formed is the degraded rim of an older crater that is ~70 km [about 44 miles] across, with a vertical drop of over 3000 meters (approximately 10,000 feet) from its rim to its floor. Even this older crater may have been affected by the uneven terrain on which it formed – its eastern rim appears to have formed on a topographic high perhaps related to the [South Pole-Aitken] basin, leaving it well above its western rim. Thus the impactor that formed Ryder crater struck the very highest point of the older crater’s rim, and in this case it is not hard to imagine that the final shape of Ryder crater was strongly affected by its lucky (or unlucky?) encounter with the extra steep slope. The high point of Ryder’s rim is approximately 1500 meters (5000 feet) higher than the low point of its rim!
Impacts tend to increase the density of the materials below, including the rim. When the Ryder impact occurred it was hitting the larger crater’s already squashed rim. The ridge thus appears to be the more resistant dense meterial of that rim, squashed further by the Ryder impact but dense enough already to survive the impact.
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.
Don’t let Hoagland see this.
Cathcer mitt crater
Looks like someone sticking out their tongue
If the tongue was longer they could call it the Gene Simmons Crater. I can see it now, there already is the KISS Army, now there would be reason to make the KISS Space Force.