# Tag Info

66

Oh, I can answer this one. In my structural geology class, we breezed over a few paragraphs on the tectonics of impact craters, but it was in the textbook, and, being space-related, I was intrigued. One note: while most of the papers you'll find are on our own geology, the moon isn't that different compositionally from Earth at all, so I'm assuming the ...

12

It might help to compare the crater formation to a drop impact: It seems that rock can behave like a viscous mass if you hit it fast enough.

12

It's actually a rebound effect that occurs with an impact forming a large crater. https://www.lpi.usra.edu/education/explore/shaping_the_planets/impact-cratering/ explains: Central peaks – Peaks formed in the central area of the floor of a large crater. For larger craters (typically a few tens of kilometers in diameter) the excavated crater becomes so ...

7

Yes, just go to https://viewer.mars.asu.edu/viewer/ctx and then enter the image ID in the Product ID field. However, note that the image IDs are slightly different from what you posted: you have to drop the part beyond W. i.e. P05_003168_1825_XI_02N002W_070331 becomes P05_003168_1825_XI_02N002W (The remaining part is the date when the image was taken, i.e....

6

Overall it seems that the NYT article has garbled the details: although the initial low-angle sunlight made Surveyor Crater look too steep, the estimated angle of about 11 degrees proved manageable by sidling down the rim. From the Apollo 12 Lunar Surface Journal transcripts and commentary by the astronauts (https://www.hq.nasa.gov/alsj/a12/a12.html): ...

6

tl;dr: Relative to Earth, the weight of an object on Mars would be about 37.36% and 38.09% on Olympus Mons and Hellas Planitia. The difference between those two is about 2.0%. That compares to only a 0.7% range on Earth. The three main terms for the phenomenon of weight on a typical rocky planet's surface are: gravitational monopole (GM) force ...

5

I did further processing on a 80x40 sub-image covering the anomalous pixels: All images are seen at a browser based 8X zoom scale (FF will dither it smoothly, which makes the lines less sharp, but almost as clear). The information in pixel x/y, RGB & 'gray scale difference' between that pixel and the surrounding pixels was calculated and shown in a ...

4

Edit prompted by DougSpace on December 30, 2015. LCROSS numbers may have been over estimated. Here's a screen capture from the Moon Society's Facebook page: I hate to break this bad news but it seems the numbers I reported below are optimistic :(. I don't have access to the 23 Sept. 2011 edition of Science. If anyone can access it and report back, I'd be ...

4

According to NASA, the deepest crater (and the widest) is the South Pole-Aitken basin, almost 1,500 miles (2500 km) across and more than five miles (8 km) deep. Wikipedia mentions Newton at 6.1 km, but another source has the depth of this crater at 8.8 km. Might be different definitions of 'depth', though. The links provided by Uwe disagree as well, ...

3

The d/D ratio of Martian craters vary from 0.1 to 0.4 with mean value of 0.23. The largest crater with diameter 33m has d/D ratio of 0.2 but smaller craters have higher d/D value. One crater has a surprisingly high d/D value: 0.5. A plot of d/D ratio vs diameter is drawn showing the variation in the values: Shallower craters have d/D values of more than 0.3 ...

3

Lunar crater catalogs usually offer the latitude, longitude and diameter of the craters as only these can be measured directly. However, the topography has been used to determine the depth in some cases. This wiki has a history and list of lunar craters.

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NASA confirms the latter - 2600m: The depth of the crater -- about 2.6 kilometers (1.6 miles) -- also demonstrates that Mojave has experienced little infilling or erosion. The terrain was mapped using stereo pairs of images from the HiRISE imager on the Mars Reconnaissance Orbiter. I believe the confusion is from comparing depth vs elevation. Mojave ...

3

The article contains several bits of information that will be useful: Extensive fields of large fractured plate-like features on a horizontal surface are visible near the south end of the High Resolution Stereo Camera (HRSC) imaging strip taken on 19 January 2004 (Fig. 1). This area has previously been covered by NASA high-resolution Mars Orbiter Camera (...

2

The Planetary Data System (PDS, pds.nasa.gov) contains data (including imagery) collected from all NASA planetary missions, including, of course, Mars. The PDS repositories include an entire archive (they call it a "node") devoted to Cartography and Imaging Sciences (the IMG node). Visit PDS: The Planetary Data System. Select the Data Search tab. In the "...

1

It helps to do the math. Tangent 21 degrees = .384 = 38.4 % grade. This is around 5 times steeper than most anything you'll see driving around the Rocky mountains of Western USA. Very difficult to climb out of, even when not wearing a bulky space suit. Important to remember, even though moon gravity is 1/6th earth (1.62m/s$^2$), there is no "terminal ...

1

Like the answer from @Jack already noted, the confusion is indeed from comparing depth vs elevation. What i really wanted to know was the depth below "sea level". With Mars Trek's "Calculate Elevation Profile" tool you can find that the floor of Mojave crater is about 5.1 km below "sea level", 600 meters lower than Gale crater's ! Together with Nicholson ...

1

It comes down to how much spacecraft you want to throw at it. Newton tells us that a high speed impactor will be basically stopped by displacing it's own mass. (Although if what it hits is hard enough it may stop sooner.) Also, an object which is very long and thin may punch a hole but not have the energy to clear the rubble away adequately. The bigger ...

1

Using @TildalWave's suggested method of estimating the depth of the regolithe, I looked for boulders penetrating the surface layer. There are a couple of them: Most notable however are the large (~10m) boulders towards the north rim of the crater. They seem to be located in a pretty shallow place, so I would say that the depth of the soil is no more ...

1

I've done an examination of the literature on the subject, and I can't find any mention of any volatiles except for water ice, but there are indicators that there should be others. Let's examine what characteristics of volatiles should be on the Lunar surface. It would have to be solid in a vacuum at low temperatures, about 100K. The material should be ...

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