1. Accelerated Expansion
And
Dark Energy

2. The Expansion of the universe is Accelerating!
Unobservable Energy is thought to drive this, “Dark Energy”

3. Evidence for Dark Energy
Distance measurements and their relation to redshift, which suggest the universe has expanded at an accelerating rate in the last half of its life.
As a result there is a need for a type of additional energy that is not associated with regular matter or dark matter
large scale wave-patterns of mass density in the universe.

4. Dark Energy is Hypothetical and thought to be …
Homogeneous…spread evenly across the Universe
not very dense
does not interact with any of the fundamental forces other than gravity.
isn’t associated with matter
Thus it is also called “vacuum energy”