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68 votes

Why are there mountains/mounds in the centre of craters on the lunar surface?

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. ...
Anton Hengst's user avatar
  • 10.7k
48 votes

Do scientist who study martian geology typically use the term areology?

Good question. I work on the Curiosity team, and I hear "geology" all the time, but never "areology." Too bad, really, since it's a great word, and I love the R/G/B Mars series.
foobarbecue's user avatar
  • 1,405
31 votes

Do other planets and moons share Earth’s mineral diversity?

We turn to Mars, which we have studied for decades now. And we do see plenty of mineral diversity on the surface of the Red Planet, it's not just rust by any means. Curiosity's CheMin analyzer has ...
Oscar Lanzi's user avatar
  • 8,525
26 votes

Rock arches on the moon?

There's a saying, "ask 4 geologists about a geological feature and you'll get 5 or 6 answers, maybe more". My interpretation of what you have highlighted is not a rock arch - an arched rock ...
Fred's user avatar
  • 13.1k
23 votes

Why is Curiosity not heading for Peace Vallis?

It is actually too likely to find water there. There are 3 categories of Planetary Protection missions for a mission to Mars, IVa, IVb, and IVc. Curiosity meets the IVa criteria, a mission not ...
PearsonArtPhoto's user avatar
  • 121k
23 votes
Accepted

Do scientist who study martian geology typically use the term areology?

A search on arXiv for "areology" produces no results. A search on ADS produces two results (one of which has the subtitle "The Geological Environment of Mars"). So the term is ...
usernumber's user avatar
  • 5,048
22 votes

Rock arches on the moon?

If it helps, following the citation trail leads to the back side of the same rock formation being visible on three other photographs on the same reel of film: https://history.nasa.gov/alsj/a16/AS16-...
SE - stop firing the good guys's user avatar
21 votes

Do other planets and moons share Earth’s mineral diversity?

They do not! The reasons for this are simple: minerals are semi-stable configurations of elements formed in certain pressure-temperature-redox conditions. A planet in the possession of active plate ...
Anton Hengst's user avatar
  • 10.7k
17 votes

Is there dirt or its structural equivalent on Mars?

The fine regolith on Mars is regarded as being the closest equivalent to an Earth like soil. It contains sand and dust. Clay deposits have been found. The two could be mixed to produce a more graded ...
Fred's user avatar
  • 13.1k
16 votes

How could InSight's seismometers be intentionally and meaningfully "pinged"?

The traditional method (as used in the Apollo project) was to crash used SIVB stages into the Moon.
Hobbes's user avatar
  • 128k
14 votes
Accepted

Were launchpads at KSC built with pilings or footings?

Based on this article, 39A is just concrete on top of sand. That does seem a little ridiculous though. The pumps piled up another portion of the dredged sand on the launch pad, creating a flat-...
Ash Pera's user avatar
  • 156
14 votes
Accepted

Difference between "mafic floor" and "olivine-bearing floor" in Jezero crater? (Perseverance landing site)

TL, DR: Olivine is a specific type of mafic or ultra-mafic mineral that is specifically identified in some parts of the overall mafic floor of the crater. The olivine is seen in specific areas of ...
Oscar Lanzi's user avatar
  • 8,525
13 votes

Why are there mountains/mounds in the centre of craters on the lunar surface?

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 ...
Oscar Lanzi's user avatar
  • 8,525
13 votes

Why are there mountains/mounds in the centre of craters on the lunar surface?

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.
Eric Duminil's user avatar
  • 1,788
12 votes
Accepted

Is there any reason Cyanobacteria or Lichens can't survive on Mars?

We don't really know. A study from 2012 suggests that lichens and cyanobacteria could indeed survive the "obvious" perils of Mars, including radiation, low pressure, and temperatures dropping as low ...
Oscar Lanzi's user avatar
  • 8,525
11 votes
Accepted

Why is the northeastern region of Syrtis Major Planum a selected landing site for the Mars 2020 mission?

Edit - added more detail on the specific geological interests per the question revision Selection Process This letter to Dr Michael Meyer, lead scientist for the Mars Exploration Program, gives a ...
Jack's user avatar
  • 9,956
11 votes

Which scientific articles together give proof of all the chemical elements found on Mars?

From Mars Fact Sheet: hydrogen (H), carbon (C), nitrogen (N), oxygen (O), argon (Ar), neon (Ne), krypton (Kr), xenon (Xe). From Inorganic analysis of martian surface samples at the viking landing ...
Cornelis's user avatar
  • 7,535
11 votes

Do scientist who study martian geology typically use the term areology?

It does not appear to be a term in common usage in formal scientific settings. Wikipedia suggests that geology is a term generalised to all planets and areology is mainly used in popular media and ...
Wiggo the Wookie's user avatar
10 votes

Would a circular saw on one arm and a trowel on another on the Mars 2020 rover add scientific value?

The rover already has a core drill for this purpose: it drills through the top layers and exposes the rock underneath. The big advantage of a drill over a shovel is that a drill can go through (most) ...
Hobbes's user avatar
  • 128k
9 votes
Accepted

Is there really a frozen lake near the equator on Mars?

This paper reports SHARAD observations of this site, and also references previous publications based on an earlier radar instrument MARSIS. It's complicated and the data seems to be ambiguous, but the ...
Steve Linton's user avatar
  • 19.6k
9 votes

Constant lunar sub-surface temperature

tl;dr: The number is often given as 252 +/- 3 K (or about -21°C or -6°F), so @BowlOfRed pretty much nailed it using first principles! Without atmosphere, equilibrium temperature at 1AU is about -17C. ...
uhoh's user avatar
  • 149k
9 votes

What is the white stuff emerging from a hole on the surface of Mars?

That's almost certainly ChemCam's laser vaporizing some rock for its spectrometer. You can see similar white spots in this video: The laser fires in short pulses 10 ...
Christopher James Huff's user avatar
9 votes

Do other planets and moons share Earth’s mineral diversity?

According to this dated but enjoyable Scientific American article https://sciences.ucf.edu/class/wp-content/uploads/sites/23/2020/01/Hazen-The-evolution-of-minerals-Scientific-American.pdf, Earth is ...
Woody's user avatar
  • 22.1k
8 votes
Accepted

Why does the Mars Global Surveyor carry a bit of the Zagami meteorite?

In case anyone doesn't know, and it's maybe not obvious from the question, this meteorite is believed to be a chunk of Mars that was knocked free by an impact a couple of million years ago. The ...
Steve Linton's user avatar
  • 19.6k
8 votes

What are the dark areas on the moon?

Wikipedia differentiates the compositions between the brighter highlands and darker maria on the Moon (citing Ref. 1): The relatively low silica content suggests that all regions are composed ...
Oscar Lanzi's user avatar
  • 8,525
8 votes

Why is Curiosity remaining on the Vera Rubin Ridge for so long?

There are several causes: delays due to operational problems. When I last left the rover back in September, it had just climbed onto Vera Rubin Ridge. Since then, it has slowly maneuvered ...
Hobbes's user avatar
  • 128k
8 votes

How could InSight's seismometers be intentionally and meaningfully "pinged"?

Let's examine what's already on InSight: A seismometer (SEIS). It's so sensitive that it is expected to be able to sense windstorms, dust devils, and the tidal forces of Mars' moon. To isolate the ...
DrSheldon's user avatar
  • 48k
8 votes

Where exactly are those eight steep slopes on Mars revealing structures of buried ice?

Scarp #1: According to this NASA information, this specific scarp is located at 56.6 degrees South latitude, 114.1 degrees East longitude. This picture was taken on May 7, 2011. I went to Google ...
8 votes
Accepted

Significance of Venus surface photos

That's what I found so far. In Abdrahimov, Basilevsky [2002] Venera photos are used for geological context interpretation comparing with orbital radar data. quotes: The photogeologic analysis shows ...
Heopps's user avatar
  • 9,061

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