The Missing Craters of Asteroid Itokawa
Explanation:
Where are the craters on asteroid Itokawa?
Missing -- unexpectedly.
The Japanese robot
probe Hayabusa
approached the
Earth-crossing asteroid
in 2005 and
returned pictures
showing a surface unlike any other
Solar System
body yet photographed -- a surface possibly devoid of
craters.
The leading hypothesis for the lack of
common circular indentations is that
asteroid Itokawa is a
rubble pile -- a bunch of rocks and ice chunks only loosely held together
by a small amount of gravity.
If so, craters might not form so easily -- or be filled in whenever the
asteroid gets jiggled by a passing planet or struck by a massive meteor.
Recent Earth-based observations of asteroid Itokawa have shown that one part
of the interior even has a
higher average interior density than the other part, another
unexpected discovery.
The Hayabusa mission returned soil samples from
Itokawa
which are also giving clues the ancient history of the
unusual asteroid
and our entire Solar System.
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.
