Linné Crater
Linné crater is a young, well preserved impact crater on the western edge of Mare Serenitatis, at coordinates: latitude = 27.7, longitude = 11.8. It is 2.2 km in diameter and bowl-shaped and is often cited as a good example of a fresh impact crater. Its actual age is unknown but thought to be less than 10 million years.
It has been used to investigate how cratering occurs in mare basalts and the report from the 42nd Lunar and Planetary Science Conference (2011) has a very good description of the crater and compares it to the terrestrial Barringer Crater (aka Meteor Crater). The report can be found here: Linne: Simple Lunar Mare Crater Geometry from LRO Observations
There is some controversy about Linné crater to do with ‘transient lunar phenomena’ (TLP) maybe caused by outgassing. In the nineteenth century some astronomers believed that they had seen changes around the crater, in some cases they said that the crater had vanished leaving only a mound behind. This is discussed here: The Linné Crater Controversy
NAC Strips: Left – M139836046LE Right – M139836046RE
[NASA/GSFC/Arizona State University]
Colour coded shaded relief map of Linné crater created from an LROC NAC stereo topographic model. The colours represent elevations; cool colours are lowest and hot colours highest.
Useful Links
LROC NAC Image of Linné Crater
The following site contains a movie of a “fly around” Linné crater:
Aristarchus
This week I’m concentrating on the Aristarchus region. Aristarchus crater was named after the Greek astronomer Aristarchus of Samos by an Italian mapmaker called Giovanni Riccioli.
The crater is relatively young, being formed approximately 450 million years ago and is one of the brightest craters on the nearside with an albedo almost double that of other similar features. It has a diameter of between 40 and 45km and a depth of 3.7km.
The following image of the Moon was taken by Jules and shows Aristarchus as the bright spot in the top left quadrant. It can be seen by the naked eye.
Jules
The Aristarchus area of the Moon is one of the most interesting and diverse regions on the nearside. It consists of a rectangular shaped plateau about 200km across which is located in the middle of the vast Oceanus Procellarum mare. This plateau was probably uplifted and tilted when the Imbrium basin was formed and has experienced much volcanic activity. The largest sinuous rille known, Vallis Schroteri, is found here and is about 160km long and up to 11km wide. The second article at the end of this post has a very interesting description of the head of the Vallis Schroteri rille and some great images.
The Aristarchus region has had many transient lunar phenomena (TLP) reported. When the Apollo 15 lander passed over this region in 1971 it recorded a significant rise in alpha particles which was believed to be caused by the decay of Radon-222. This radioactive gas has a half-life of only 3.8 days and is thought to be released through tidal stresses.
The following image shows the Aristarchus region. Aristarchus crater is on the left with Herodotus crater on the right and the Vallis Schroteri rille starting below it.
Nasa image from the Apollo 15 Mapping Camera
Some images of the Aristarchus area posted by users of the Moon Zoo forum:
Part of the collapsed walls of Aristarchus. Geoff
ID: AMZ400432i
Latitude: 24.199° / Longitude: 312.434°
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Impact melt in Aristarchus crater. Tom128
# ID: AMZ10036sv
# Latitude: 24.3744° / # Longitude: 312.405°
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Interesting terrain in Aristarchus area. DJ_59
ID: AMZ300013p
Latitude: 23.9853° / Longitude: 312.908°
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More interesting terrain. Thornius
# ID: AMZ2000985
# Latitude: 23.5672° / # Longitude: 312.451°
Articles
An article from LROC about the geology of the central peak of Aristarchus crater and how the different rock types exposed by the impact help geologists to see what the interior of the Moon is made from.
Aristarchus – Up from the Depths
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An article from the Space Fellowship site discussing the Cobra Head feature which is thought to be the source vent of a tremendous outflowing of lava that formed the Vallis Schroteri rille.