The steep interior rim of Aristarchus Crater
Click for larger image.
Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, is a just released image taken by Lunar Reconnaissance Orbiter, looking across the top of Aristarchus Crater on the Moon from a height of only 60 miles, with the dark surrounding plateau in the foreground contrasting sharply with the bright crater interior. For scale, the distance from the floor of the crater to the top of the rim is about 9,000 feet. The bright central peak is about 1,300 feet tall. The contrast in brightness inside and outside the crater is explained thus:
Adjacent to Aristarchus crater is the Aristarchus plateau, one of the largest volcanic centers on the Moon. Here we find one of the largest rilles [on the Moon, dubbed Vallis Schröteri], a massive pyroclastic deposit, and the source of extensive flood basalts.
These volcanic materials are considered relatively young (for the Moon) – 1.5 to 2.5 billion years. The pyroclastic deposit formed when magma was explosively ejected from the vent and broke into small droplets quenched as glass in the cold vacuum of space as they fell back to the surface. Due to their high glass content, the pyroclastic deposits are distinctly low in albedo (relatively dark), providing a dark background for the bright Aristarchus crater. Within the crater, some of these pyroclastic deposits may be visible as the darkest areas on the far wall, and glassy impact melt is moderately lower in reflectance than the bright, rocky materials exposed on areas of the crater floor and walls.
The overview map below shows both the crater and the vent from which Vallis Schröteri belched.
Click for full image.
This view comes from an earlier LRO image inspecting the boulders on the floor of Aristarchus. The two white lines indicate approximately the area seen in the oblique view above. The beginning of the Vallis Schröteri, also nicknamed the Cobra’s Head by many astronomers, can be seen as the large dark canyon at center left. It begins at this point and meanders to the west for another 100 miles. That beginning point is a deep pit that is thought to be the vent from which the lava flowed. Its connection to Aristarchus is obvious, though the exact geological story remains unsolved.
Two other earlier cool images of Aristarchus can be viewed here and here. All illustrate the tragedy of the cancellation of the Apollo 18 mission in the 1970s, as that manned flight was going to land at this spectacular location.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the 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. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
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
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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.
Click for larger image.
Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, is a just released image taken by Lunar Reconnaissance Orbiter, looking across the top of Aristarchus Crater on the Moon from a height of only 60 miles, with the dark surrounding plateau in the foreground contrasting sharply with the bright crater interior. For scale, the distance from the floor of the crater to the top of the rim is about 9,000 feet. The bright central peak is about 1,300 feet tall. The contrast in brightness inside and outside the crater is explained thus:
Adjacent to Aristarchus crater is the Aristarchus plateau, one of the largest volcanic centers on the Moon. Here we find one of the largest rilles [on the Moon, dubbed Vallis Schröteri], a massive pyroclastic deposit, and the source of extensive flood basalts.
These volcanic materials are considered relatively young (for the Moon) – 1.5 to 2.5 billion years. The pyroclastic deposit formed when magma was explosively ejected from the vent and broke into small droplets quenched as glass in the cold vacuum of space as they fell back to the surface. Due to their high glass content, the pyroclastic deposits are distinctly low in albedo (relatively dark), providing a dark background for the bright Aristarchus crater. Within the crater, some of these pyroclastic deposits may be visible as the darkest areas on the far wall, and glassy impact melt is moderately lower in reflectance than the bright, rocky materials exposed on areas of the crater floor and walls.
The overview map below shows both the crater and the vent from which Vallis Schröteri belched.
Click for full image.
This view comes from an earlier LRO image inspecting the boulders on the floor of Aristarchus. The two white lines indicate approximately the area seen in the oblique view above. The beginning of the Vallis Schröteri, also nicknamed the Cobra’s Head by many astronomers, can be seen as the large dark canyon at center left. It begins at this point and meanders to the west for another 100 miles. That beginning point is a deep pit that is thought to be the vent from which the lava flowed. Its connection to Aristarchus is obvious, though the exact geological story remains unsolved.
Two other earlier cool images of Aristarchus can be viewed here and here. All illustrate the tragedy of the cancellation of the Apollo 18 mission in the 1970s, as that manned flight was going to land at this spectacular location.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the 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. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
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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