© NASA/JPL-Caltech
Artist’s depiction of a collision between two planetary bodies. New research suggests the stark difference between the Moon’s heavily-cratered farside and the lower-lying open basins of the nearside were caused by a wayward dwarf planet colliding with the Moon in the early history of the solar system.
Artist’s depiction of a collision between two planetary bodies. New research suggests the stark difference between the Moon’s heavily-cratered farside and the lower-lying open basins of the nearside were caused by a wayward dwarf planet colliding with the Moon in the early history of the solar system.
Now, new evidence about the Moon's crust suggests the differences were caused by a wayward dwarf planet colliding with the Moon in the early history of the solar system. A report on the new research has been published in AGU's Journal of Geophysical Research: Planets.
The mystery of the Moon's two faces began in the Apollo era when the first views of its farside revealed the surprising differences. Measurements made by the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012 filled in more details about the structure of the Moon - including how its crust is thicker and includes an extra layer of material on its farside.
There are a number of ideas that have been used to try and explain the Moon's asymmetry. One is that there were once two moons orbiting Earth and they merged in the very early days of the Moon's formation. Another idea is that a large body, perhaps a young dwarf planet, found itself in an orbit around the Sun that put it on a collision course with the Moon. This latter giant impact idea would have happened somewhat later than a merging-moons scenario and after the Moon had formed a solid crust, said Meng Hua Zhu of the Space Science Institute at Macau University of Science and Technology and lead author of the new study. Signs of such an impact should be visible in the structure of the lunar crust today.
"The detailed gravity data obtained by GRAIL has given new insight into the structure of the lunar crust underneath the surface," Zhu said.
Comment: For more on our changing skies, see:
- Our changing atmosphere: Stunning iridescent cloud over Mexico, complex solar halo over Russia and a triple rainbow over Norway
- Strange skies: Red Sprites in Oklahoma, aurora Steve in Canada, iridescent clouds in Illinois and noctilucent clouds in Denmark
- Strange but beautiful skies: Noctilucent 'tornado' cloud, auroras, double and twin rainbow plus a midnight rainbow
- Chemtrails? Contrails? Strange Skies
- The phenomenon STEVE is not an Aurora after all
For an idea of what's driving these changes, check out SOTT radio's Behind the Headlines: Earth changes in an electric universe: Is climate change really man-made? as well as our monthly documentary SOTT Earth Changes Summary - April 2019: Extreme Weather, Planetary Upheaval, Meteor Fireballs: