Planet Mercury Shrunk Far More Than Previous Estimates
Monday, March 17, 2014 - 04:20
in Astronomy & Space
New evidence gathered by NASA's MESSENGER spacecraft at Mercury solves an apparent enigma about Mercury's evolution. The data indicate the tiny planet closest to the sun, only slightly larger than earth's moon, has shrunk up to 7 kilometers in radius over the past 4 billion years, much more than earlier estimates. Older images of surface features indicated that, despite cooling over its lifetime, the rocky planet had barely shrunk at all. But modeling of the planet's formation and aging could not explain that finding. read more