QUESTION:
Is it true that the earth is slowly going out of its orbit?
If so, what will happen to the earth?

Answer from Ed Colbert on April 23, 1996:
There are many things that could happen to force the Earth out of its "perfect"
orbit around the Sun, but rest assured that the effects are very small during
a million-year period (approximately how long humans have been known to be on
the Earth).  Gravity is the most influential force in our solar system and the
only other massive object in our solar system other than the Sun is Jupiter.
You probably know that things that come near Jupiter get really torn apart.
Just look at the asteroid belt.  There would have probably been one of more
planets there if Jupiter was the same mass as the Earth.

I suppose if a large asteroid came near the Earth it could push it a little out
of its orbit, but not enough to let it escape from the gravity of the Sun.  It
would still orbit around in the same way, but it may orbit in some kind of
oscillating pattern around its normal circular orbit.

If there were air in space like there is on the Earth, then it would be a whole
different story.  The friction from the air would cause the Earth to lose
energy and it would eventually spiral into the Sun.  Good thing there isn't
any air out there!

If a large asteroid actually hit the Earth, then we would all be goners anyway.
Even if that happened, the gravity of the Sun would tug on whatever is left and
make it orbit around the Sun.

So, sleep soundly -- the Earth is in the good hands of our Sun!