1. Cosmology
study of the structure and evolution of the entire universe
2. Cosmological Assumptions
A. Universality of Physical Law
B. Homogeneous universe
C. Isotropic universe
D. Universe has no center
B & C together are known as the "cosmological principle"
3. Olbers' Paradox
Sky should be bright at night
4. Big Bang Theory
Universe has been expanding for nearly 10-15 billion years
Explains:
recession of galaxies (Hubble's Law)
Universe had early history (quasars)
cosmic microwave background
helium abundance
Important point in Big Bang Theory
space actually expands
5. Einstein's General Theory of Gravitation
Three possibilities for universe
open (infinite and unbounded)
flat (infinite and unbounded)
closed (finite and unbounded)
6. Future of the universe
depends on density of matter
larger than critical density -> universe will recollapse
and universe is closed
less than critical density -> universe will expand forever
and universe is open