Dark Energy What is dark energy Theorized force

Dark Energy

What is dark energy? • Theorized force opposing gravity. • This force would accurately explain the current accelerating expansion of the universe. • Possible it might be related to the inflation period of the early universe.

Supporting Evidence • Measurement of supernovae type Ia, SN 1997 ff, actually predicted to be brighter than it appears in space, thus providing evidence that universe is expanding.

other Defining Properties • Dark Energy is said to be uniform through out space

Supporting Fact • CMB anisotropy indicate the universe is flat. • Thus, matter density + energy density = critical density. • But, matter density only contributes 1/3 of the critical density! • So, in order for energy density to have escaped detection it must be distributed uniformly.

Importance of Dark Energy • Currently it is estimated that the composition of the universe is approx. 70% dark energy • 25% dark matter • 2 -5 % matter (stars, H, He, neutrinos, heavy elements)

Importance of Dark Energy • Possibly predict the future of the universe. • If repulsion from dark energy becomes strong, could potentially lead to a Big Rip. • Or, a variable dark energy might fade away and then flip into a future that pulls the universe together rather then pushing it apart, into a Big Crunch

References • Dark Energy and the New Cosmology, http: //supernova. lbl. gov/~evlinder/turner. pdf • Dark Energy by Wikipedia http: //en. wikipedia. org/wiki/Dark_energy