Our moon looks pretty festive in this image. That’s because it’s actually a map of the moon’s gravity, based on data gathered by NASA’s Gravity Recovery and Interior Laboratory mission, or GRAIL. And by showing us how the moon’s gravity changes, it also shows the orb’s mass and density, revealing impact marks and the thickness of the crust.
But how did the mission’s twin probes measure the moon’s gravity field in the first place?
“The map was created by the spacecraft transmitting radio signals to define precisely the distance between them as they orbit the moon in formation. As they fly over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.”
You can read more about the map and the GRAIL mission at NASA’s website.
Image courtesy of NASA/JPL-Caltech/MIT/GSFC