A Spherule from the Earths Moon
Explanation:
How did this spherule come to be on the Moon?
When a
meteorite strikes the Moon, the
energy
of the impact melts some of the
splattering rock, a fraction of which might cool into tiny
glass
beads.
Many of these
glass beads were present in
lunar soil samples returned to Earth by the
Apollo
missions.
Pictured above is one such glass
spherule that measures only a quarter of a
millimeter across.
This
spherule
is particularly interesting because it has
been victim to an even smaller impact.
A miniature
crater is visible on the upper left, surrounded
by a fragmented area caused by the
shockwaves of the
small impact.
By
dating many of these impacts, some
astronomers estimate that
cratering on our Moon
increased roughly 500 million years ago and continues even today.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
