Astronomy Picture of the Day

A Spherule from the Earth's Moon

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#100683 by @ 21.05.2007 00:00 - nach oben -
A Spherule from the Earth's Moon

How did this spherule come to be on the Moon?

When a meteorite strikes the Moon, the
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
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
astronomers can estimate the history of
cratering on our Moon.

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