(Submitted June 11, 1997)
If all the distant galaxies are flying away from us, does that mean that
we're in the center of the Universe?
Thanks for your question. Astronomers and physicists
interpret the result that all distant galaxies are flying away
from us as evidence for the uniform expansion of the Universe.
In this case, any observer, at any location in the Universe,
observes the same general motion: that the further a galaxy is
from us, the faster its relative velocity with respect to the
observer is. The famous (and very illustrative) example of this
is to imagine a loaf of raisin bread as it is baking. The raisins
in the bread spread away from one another as the loaf rises and
expands during the baking. Pick any raisin and pretend you are
standing on it (you're very small now!) and measuring the rate at
which the other raisins are moving away from you. You will find
that, no matter which raisin you choose, all other raisins appear
to be moving away from you, with the furthest raisins receding the
The current cosmological model of the Universe supposes that
our position within the Universe is typical, not special. We are not
located at the center of the Universe, but are rather taking part in
its global expansion. I hope this answers your question.
for the Ask an Astrophysicist