A Spherule from Outer Space
Explanation:
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.
Tomorrow's picture: off on a comet
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.
