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what are spaCe roCks
made of?
From Earth, we cannot tell what is inside comets, asteroids or
meteoroids. Through space exploration, scientists have learned many
things about these space rocks. Spacecraft send information to Earth,
which tells us much more about what these space objects are made of
and what their surfaces are like.
Asteroids are mostly made of rock
Most asteroids are made of rock. Some are made from metal and have a heavy
iron core. Very few are made of half metal and half rock. Scientists believe that most
asteroids are solid. Others are made of bits of rocks and dust that are stuck together
by gravity.
Asteroids are covered in regolith
Asteroids are covered in a layer of fine rock and dust
called regolith. Larger asteroids are round, while
smaller asteroids are irregular in shape. All asteroids
have craters, or deep holes, that were made by space
object impacts.
Some asteroids are solid rock or metal, but others are made up of
rock and gravel.
This asteroid is called 243 Ida and is located in
the Main Belt. It is covered in craters and has
a thick layer of regolith.
Space rock fact
Asteroids can be large or
tiny, but most are less than
100 metres across. The largest
asteroid is Ceres, which is almost
1000 kilometres across. Because
it is so large and round, some
scientists say that it is really
a dwarf planet.
Pile of large rocks
with a dust covering
Solid rock or metal
with cracks
Solid rock
or metal
Pile of fine rock with
a dust covering
