[net.astro] StarDate: March 13 Ceres

dipper@utastro.UUCP (Debbie Byrd) (03/13/86)

The largest asteroid in our solar system is Ceres -- and it's now in
our sky all night long.  More -- after this.

March 13  Ceres

Astronomers thought they had discovered another planet when they found
Ceres in 1801.  Ceres was the first asteroid known -- and it's still
the largest known asteroid.

Both planets and asteroids probably formed around the same time --
asteroids just didn't make it to planet size.  Instead, the largest
asteroid, Ceres, is about one-third the size of Earth's moon.
Asteroids and planets have similar properties and each has unique
surface features.  But the distinction between them sometimes gets a
little fuzzy.  For example, the planets in our solar system all tend to
lie in the same plane, the same flat sheet of space around the sun.
This isn't true of Pluto, though -- and some astronomers think that
tiny Pluto is really a kind of asteroid -- that there may be other
little worlds like Pluto in the outer solar system.

The asteroid Ceres is dark and rocky.  From its pitted surface, the
view of the night sky would look very much like the view from Earth.
Though Ceres orbits in the asteroid belt between Mars and Jupiter, its
neighboring asteroids would appear as distant stars -- because the
asteroids in the belt are very far apart.

Ceres is just past opposition -- when it made a line with the Earth and
sun, with Earth in the middle.  Ceres is barely visible to the naked
eye around now.  But to see it you would need a very dark sky -- and
you'd need to chart the surrounding stars for several nights -- to note
which glowing point moved against the background of the others.

Script by Holly Clark.
(c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin