The first complete topographic map of the moon and its craters has
revealed details of billions of years of bombardment by asteroids, and
the early history of our solar system. Among other things, the map
confirms theories of an onslaught of massive asteroids around 3.9
billion years ago that likely evaporated any water present on Earth at
the time.
"Ever since the surface of the moon could be photographed, scientists
have
counted craters on the moon and tried to decipher the
projectile-bombardment rate and the geological history of the moon,"
said geologist James Head of Brown University, lead author of the study
in Science Sept. 16. "But until now we've had uneven or low-resolution
coverage."
The map was created using data from NASA's Lunar Reconnaissance Orbiter
that has been circling the moon since June 2009. The orbiter measured
the
height of the surface by sending billions of laser pulses towards the
surface
and measuring the time it took for the pulses to return. The method is
precise enough it would have been able to detect a small house if there
were
one, Head said.
Read more:
http://ow.ly/2GNRn
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