What is dark energy?
Dark energy is the name given to the force that is believed to be making the universe larger.
Distant galaxies appear to be moving away from us at high speed: the idea is that the universe
is getting bigger and has been since the Big Bang. Measurements are now accurate enough
to allow astronomers to tell that these galaxies seem to be accelerating away from us. The
universe is expanding at an increasing rate.
This faster and faster expansion is not understood by scientists. There are many ideas for
what might be causing the rapid expansion. However, at the moment, cosmologists who
study it do not have a Janswer. It is as if there was something there in empty space providing
a repulsive force (Anti-gravity) that makes the universe expand. This has been named dark
energy