A young lunar impact crater
Cool image time! The science team from Lunar Reconnaissance Orbiter (LRO) today released a new image, taken on November 3, 2018, of a relatively young small crater not easily seen from Earth.
The unnamed crater, just 1.8 kilometers across, is too small to see from Earth with unaided eyes. It is in the Moon’s wild west, just past Oceanus Procellarum and close to the line dividing the nearside from the farside, so it would be hard to glimpse in any case. If you stood on the crater rim, you would see the Earth forever slowly bobbing up, down, and sideways close to the eastern horizon.
The image above is a cropped and reduced-in-resolution section of the released image. If you click on it you can see this section at full resolution.
What I find fascinating about this crater are the black streaks that appear to only run down the outside slopes of the eastern rim, but nowhere else. At first glance it looks like prevailing winds, blowing from the west, caused this, but of course that’s wrong because the Moon has no atmosphere. The website explains:
Notice the thin dark streamers of late-stage ejecta — material the small asteroid that excavated the crater lofted at a steep angle, so that it soared high and landed last, drawing fine lines on the just-deposited bright ejecta near the crater.
In other words, the impact hit the ground from an oblique angle, from the west, throwing up ejecta mostly to the east and thus producing these dark streaks. This does make sense, as research has shown that craters will still form circular pits, even if the impact comes from the side.
The full resolution image is very impressive, as you can zoom in and see many individual boulders. In fact, the interior of the crater is littered with them, With a resolution on the full image of about 16 feet per pixel, many of these boulders are house and mansion-sized, with much evidence of numerous avalanches and landslides within the crater.
Very rough country, indeed. And it gives a sense of the slowness of the lunar erosion processes, caused almost entirely by the solar wind and the tiny rain of micro-meteorites over eons. Though this crater is young, estimated to be about 100 million years old, it still looks fresh and rough. To smooth things out on the Moon will take many more hundreds of millions of years.
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 science team from Lunar Reconnaissance Orbiter (LRO) today released a new image, taken on November 3, 2018, of a relatively young small crater not easily seen from Earth.
The unnamed crater, just 1.8 kilometers across, is too small to see from Earth with unaided eyes. It is in the Moon’s wild west, just past Oceanus Procellarum and close to the line dividing the nearside from the farside, so it would be hard to glimpse in any case. If you stood on the crater rim, you would see the Earth forever slowly bobbing up, down, and sideways close to the eastern horizon.
The image above is a cropped and reduced-in-resolution section of the released image. If you click on it you can see this section at full resolution.
What I find fascinating about this crater are the black streaks that appear to only run down the outside slopes of the eastern rim, but nowhere else. At first glance it looks like prevailing winds, blowing from the west, caused this, but of course that’s wrong because the Moon has no atmosphere. The website explains:
Notice the thin dark streamers of late-stage ejecta — material the small asteroid that excavated the crater lofted at a steep angle, so that it soared high and landed last, drawing fine lines on the just-deposited bright ejecta near the crater.
In other words, the impact hit the ground from an oblique angle, from the west, throwing up ejecta mostly to the east and thus producing these dark streaks. This does make sense, as research has shown that craters will still form circular pits, even if the impact comes from the side.
The full resolution image is very impressive, as you can zoom in and see many individual boulders. In fact, the interior of the crater is littered with them, With a resolution on the full image of about 16 feet per pixel, many of these boulders are house and mansion-sized, with much evidence of numerous avalanches and landslides within the crater.
Very rough country, indeed. And it gives a sense of the slowness of the lunar erosion processes, caused almost entirely by the solar wind and the tiny rain of micro-meteorites over eons. Though this crater is young, estimated to be about 100 million years old, it still looks fresh and rough. To smooth things out on the Moon will take many more hundreds of millions of years.
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
I propose to IAU that it be named Zimmerman Crater (places on the moon are supposed to be named after states of mind (ie: Sea of Tranquility) but when the Russians took the first photos of the far side of the moon, they wanted a crater named Moscow. The IAU agreed, which means that, to astronomers, Moscow is a state of mind (you can take that and run with it), so there is a precedent.)