physnotes_week_14.pdf PHYS 104-01
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This 2 page Class Notes was uploaded by Sophie Stella on Sunday May 15, 2016. The Class Notes belongs to PHYS 104-01 at University of St. Thomas taught by Dr. Ruch in Winter 2016. Since its upload, it has received 22 views. For similar materials see Astronomy in Astronomy at University of St. Thomas.
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Date Created: 05/15/16
PHYS 104: Astronomy Week 14 Course Notes, 5/9 - 5/13 Definitions The Cosmic Microwave Background: The fog before the photons escaped after the big bang. This is found at the edge of the detectable universe. (This image shows the cosmic microwave background as viewed from Earth. The temperature fluxuations shown are the variations in density.) V. The Big Bang If we can find the expansion rate of the universe, we can find its age. A. The observable edge of the universe shows what objects looked like at the time of the big bang, and everything in front of it is shown at a time long ago but getting closer to current time as they get closer in distance. B. How we imagine the big bang: 1. Time and space spontaneously come into existence. 2. Quarks form, but are too hot to fuse together. 3. About one second into time now: quarks begin to combine to form protons and neutrons. 4. The universe is opaque a. The density is too high for photons to escape. 5. About 380,000 yrs into time: light photons begin to escape the fog of matter. 6. High-density places in the fog become galaxies. a. Galaxies are found to have been formed in a sponge-like order, like bubbles with pockets of empty space between them. (the colored spots in the photo show higher densities of galaxies. The black shows places where there is just empty space. VI. The Shape of the Universe A. Gravity warps space: this leaves three options for the universe on a large scale. 1. Closed a. Shaped like the rubber of a blown balloon. If you started travelling in any direction without changing course, you would eventually come to the same spot. 2. Open a. Basically a flat universe, which is highly unlikely based on. 3. Open, but with some curviture like the closed universe. B. Our measurements of the detectable edge of the universe surprisingly give evidence of an open, flat universe. VII. The Mass of the Universe A. All current models of the universe must include dark matter in order to work. 1. They include 30% matter (dark matter as well as other stuff) 2. They also include 70% Dark Energy. (This is where the theory for the Ether came in) B. We have no concept or understanding of this dark energy, or of dark matter. Something is fundimentally incorrect about our understanding of the universe. VIII. The Fate of the Universe A. Escape Velocity, on a universal scale 1. If we are in an open universe, it will keep expanding forever. 2. if we are in a closed universe (if the universe has a critical density), it will shrink back down and the big bang will happen again. B. Data has shown that the universe is expanding exponentially (everything is accelerating further), which is why the open universe theory is plausible. 1. Eventually everything will be expanding so fast that gravity won't hold it together.
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