 Centaur's
bright surface spot could be crater of fresh ice.
The unexpectedly
varied surface of a wayward piece of space debris has given astronomers
new insights into the characteristics and behavior of centaurs,
ghostly comet-like bodies that lie just beyond Pluto's orbit.
While using
NASA's Hubble Space Telescope to observe Centaur 8405 Asbolus,
a 48-mile-wide chunk of ice and dust that lies between Saturn
and Uranus, astronomers were surprised to find that one side of
the object looks like it has a fresh crater, less than 10 million
years old.
The finding
poses a mystery because the underlying ice exposed by the crater
is unlike any yet seen, say researchers. "This shows that
these mysterious objects do not have a simple homogenous surface,"
said a Hubble program spokesman.
Scientists
using Hubble didn't directly observe the crater because it is
too small and far away. Instead, its surface composition was determined
by using the space telescope's near-infrared camera to determine
the chemical composition of the ice.
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