240 likes | 337 Views
Olber’s Paradox. The universe is expanding!. Hubbles Law. Four Main Issues. Cosmic Microwave Background (CMB) Large Scale Structure Universal Acceleration Gravitational Leaks. Sachs-Wolfe effect. DARK MATTER:. Gravity from baryons alone could not account for fluctuations.
E N D
Four Main Issues • Cosmic Microwave Background (CMB) • Large Scale Structure • Universal Acceleration • Gravitational Leaks
DARK MATTER: • Gravity from baryons alone could not account for fluctuations. • The ratios of the power spectrum peaks indicate relative dark matter density. • Dark matter comprises 25% of the critical density.
Acceleration • Has the universe always been accelerating? • If not, when did it start, and what is causing it?
Repulsive Gravity? • Matter and Energy produce gravity. • The amount (density) of matter and energy in the universe determines the rate that it will slow down. • GR allows for repulsive energies (Dark Energy)
As the universe expands, the matter density decreases. The dark energy density remains the same. Or does it…?
There are theories suggesting that: DARK ENERGY INCREASES DARK ENERGY DECREASES GENERAL RELATIVITY NEEDS FIXING