History of Cosmology. Newton to The Big Bang. What is science?. a) Finding the truth. b) A set of facts. c) Performing experiments and observations. d) All of the above. What is the difference between scientific laws and theories?. Laws have been proven. Theories have not been proven.
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Newton to The Big Bang
a) Finding the truth.
b) A set of facts.
c) Performing experiments and observations.
d) All of the above.
Period-Luminosity Relation for Cepheid’s and
RR Lyrae Variable stars.
In 1923, Edwin Hubble was examining photographic plates of the Andromeda Nebula taken with the 100-inch telescope in order to find novae -- stars that would suddenly increase in brightness. On this place from the night of October 5-6, 1923,
Hubble located three novae, each marked with an ``N.'' One of these novae, however, turned out to be a Cepheid variable, a star that changes predictably in brightness, and the ``N'' was crossed out and the star was relabeled ``VAR!'' This Cepheid, and others subsequently discovered in the Andromeda Nebula, enabled Hubble to prove that the Nebula was not a star cluster within our own Milky Way, but a galaxy more than a million light years away.
where V = velocity
D = distance
H = Hubble’s constant (slope of the line)
center of the universe?
The entire Universe is expanding similar to an expanding raisin cake.
There is NO center to the expansion. Every raisin is getting farther
away from every other raisin.
No matter which raisin you live on, ALL other raisins appear to be
going away from you.
As the universe expands
it should cool. Gamow
predicted the universe
should now have a black
body curve following
3 Kelvin, observable in
Why does the early Universe look the same in all directions?
Rapid expansion says that universe expanded so fast that it could remember how its neighbors looked.
The Universe appears to have formed with exactly the amount of mass necessary to make it flat. WHY?
1) A low density universe will expand forever.
2) A high density universe will collapse in the Big Crunch.
At the moment we cannot
tell the difference.
Critical density is the density that is
required to cause the universe stop
expanding in infinite time.
This is inconsistent with The Big Bang Model!!!!!!
Again it is very difficult to sort out how the universe will end!
This is the fun of science and it is why humans DO science!
Chaisson & McMillan, (2002, 2004). Astronomy Today (4th & 5th Ed.)
Bennett et al. (2004) The Cosmic Perspective (3rd Ed.)
Shipman, Wilson, and Todd, (2003). An Introduction to
Physical Science (10th Edition).