GRAIL and the Mystery of the Missing Moon
September 8, 2011
Written by Dauna Coulter
Science@NASA
Pasadena, CA – As early as September 8th, NASA’s GRAIL mission will blast off to uncover some of the mysteries beneath the surface of the Moon. That cratered gray exterior hides some tantalizing things – even, perhaps, a long-lost companion.
The “Big Splat.” Four snapshots from a computer simulation of a collision between the Moon and a smaller companion show how the splattered companion moon forms a mountainous region on one side of the Moon. Credit: M. Jutzi and E. Asphaug, Nature. [more] If a paper published recently in the journal Nature* is right, two moons once graced our night skies. The proposition has not been proven, but has drawn widespread attention.
Flying in formation around the Moon, NASA's twin GRAIL spacecraft will make precise measurements of the lunar gravitational field.
