All the individual stars you see are in the Milky Way galaxy. Until the
1920's, that seemed to be the only galaxy. You probably know, though,
that observations with larger telescopes have since proved otherwise.
Our universe contains at least 50,000,000,000 galaxies. We do not mean
50 billion stars-but at least 50 billion galaxies, each with billions
of stars like our sun. Yet it was not the staggering quantity of huge
galaxies that shook scientific beliefs in the 1920's. It was that
they are all in motion.

Astronomers discovered a remarkable fact: When galactic light was
passed through a prism, the light waves were seen to be stretched,
indicating motion away from us at great speed. The more distant a
galaxy, the faster it appeared to be receding. That points to an
expanding universe!

Even if we are neither professional astronomers nor amateurs, we can
see that an expanding universe would have profound implications about
our past-and perhaps our personal future too. Something must have
started the process-a force powerful enough to overcome the immense
gravity of the entire universe. You have good reason to ask, 'What
could be the source of such dynamic energy?'

Although most scientists trace the universe back to a very small, dense
beginning (a singularity), we cannot avoid this key issue: "If at
some point in the past, the Universe was once close to a singular
state of infinitely small size and infinite density, we have to ask
what was there before and what was outside the Universe. . . . We
have to face the problem of a Beginning."-Sir Bernard Lovell.

This implies more than just a source of vast energy. Foresight and
intelligence are also needed because the rate of expansion seems very
finely tuned. "If the Universe had expanded one million millionth
part faster," said Lovell, "then all the material in the Universe
would have dispersed by now. . . . And if it had been a million
millionth part slower, then gravitational forces would have caused the
Universe to collapse within the first thousand million years or so of
its existence. Again, there would have been no long-lived stars and no
life."