(Submitted March 14, 1997)
What keeps the stars from crashing into each other?
There is a very short answer to your question, and that is
that space is very large, and there is lots of room for stars, moons, and
planets to move around without colliding with each other. Often, when
two objects look close together on the sky, one of them is much further
away than the other. Therefore, they are not really close together
at all. This is true for many of the stars in the constellations that
we are familiar with, and it is true for stars and planets which look
close to our Moon. The nearest stars are light years away, while the
Moon is about a billion times nearer. Collisions between stars are
believed to happen, but they must be very infrequent. Collisions
inside our solar system happen fairly often between planets and
comets or meteors. Each "shooting star" is an example of
such a collision, and 2 years ago a fairly large comet collided with Jupiter.
I hope this helps!
for the Ask an Astrophysicist team