Sep. 21 – 2B03 21/09/2011 9:29:00 AM
Extensions on deadlines:
Project sign up: Sept. 30
Project proposal: Oct 7 th
Cosmology – study of the origin and evolution of the universe
1) Distances to other galaxies -> standard candles (observed
brightness vs. true brightness)
2) Doppler shift – shifting red or blue
In our telescopes, we install a prism (or a grading) which measures the
spectrum of light.
After it passes through a prism, you can see how much light is in
each of the spectrum colours.
In Astronomy, we have 2 ways to collect data:
2) Spectroscopy - measuring the spectrum of light.
Farther away a galaxy is, the faster it is moving away.
Its not that galaxies are moving away RELATIVE TO US, its that
everything is moving away from everything.
V = Hd
Implications of Hubble's Law
1) As time goes on, galaxies should be more and more farther
apart. If we moved time backwards, galaxies should be moving
o We can look back in time, lookback time!
Density of galaxies goes up in the past -> exactly what Hubble
predicted w/ expanding universe. Analogy of universe to raisin bread.
o As the bread rises, raisins get further apart.
2) The universe may have had