Class Notes 3/23

Olber's Paradox

1. Newtonian idea of the universe assumes infinite universe and infinite number of stars with homogeneous distribution
2. Number of stars of distance d is about d^2
3. L = b/(4πd^2)

Hubble

1. Discovered galaxies and the enormous number of them
2. The further away a galaxy was the more the Hydrogen spectrum was shifted toward the red.
3. v = H0(d) where H0 is called Hubble's constant
4. (∆λ) / (λref) = v/c
5. The universe is expanding leading to the Big Bang cosmology.
6. Ho = 2.2 x 10^4 m/sMly
7. From v = H0(d) and d = v(avg)T:
   T = d/v(avg) = 1/H0

Schwarzchild Radius:

R = (2GM) / (c^2)