Astro Blog

https://eos.org/articles/the-quaking-shrinking-moon Source:   By Rachel Crowell, Eos/AGU. Excerpt: New evidence suggests that the Moon may still be tectonically active. Between 1969 and 1977, lunar seismometers at four Apollo landing sites recorded 28 shallow moonquakes. However, the data transmitted by those seismometers were low resolution by current standards, making it difficult to locate the moonquakes’ epicenters. ...The orbital timing of these quakes was also significant. Seven of them occurred at near apogee, when compression of the Moon is near its maximum and fault slip events are likely to occur, according to the study. ...Although these results illustrate an exciting discovery, they also show the need for putting modern seismometers on the Moon....  

https://www.nytimes.com/2019/05/01/science/moon-earth-collision.html Source:   By Robin George Andrews, The New York Times. Excerpt: ...A study [ https://www.nature.com/articles/s41561-019-0354-2 ] published on Monday in Nature Geoscience suggests that the moon was forged from the fires of an ocean of magma sloshing over baby Earth’s surface. If correct, this model may solve a longstanding paradox. Lunar meteorites and samples collected during the Apollo missions show that the moon and Earth have remarkably similar geochemical fingerprints. Scientists suspect that this was likely the result of a giant impactor the size of Mars, known as Theia, that slammed into a young Earth and sent into orbit a spiral of material that coalesced into the moon. Countless computer simulations show that this is possible, but there’s a problem. Such an impact on a relatively solid Earth would have created a moon made mostly out of Theia, not Earth (at least in simulations resulting in the Earth-moon s