HISTORY 2720 Lecture Notes - Lecture 6: Gravitational Lens, Observable Universe, Vera RubinPremium
3 pages89 viewsSpring 2018
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Everything was uniform and simple in the beginning, same temp and look○
Lots of matter
Gravity - more powerful when stuff is closer/denser
Tiny differences in distribution of matter (1/1000000 of a degree difference in
Complex things happen when you have perfect Goldilocks conditions:○
Gravity continued to bring these tiny differences closer together, causing heat and
energy to be formed by the bumping atoms
Universe is cooling down, suddenly heating up for first time. ~3,000 degrees atoms can
hold together. Creates plasma that raises to ~10,000,000 degrees. Nuclear fusion
causes stars to light up. Threshold 2
Stars: protons at extremely high temps. Photons work through surrounding
plasma to provide a light
Superclusters: webs and chains of clusters. At this scale, you can see the
superclusters moving farther away from each other. Galaxy doesn't hold these
together - we're expanding
Clusters: group of galaxies
Now we're filled with stars that are still being born in star nurseries. Provided us with
These stars provide us with 'campfires in Antarctica' that have goldilocks conditions
Big History Project - How were stars formed?
A: the stars!
Stars heating up cooked up the elements of the universe
Surface of sun ~5,800 degrees. Core ~15,000,000 40,000x hotter than boiling water.
Hydrogen protons heated to form helium. Carbon has 6 protons so it needs more heat.
Each element higher needs more tempertaure.
Q: Where did all the element come from?
A: In dying stars○
Most of their life they are fusing hydrogen to helium. The collapse of gravity creates a
lot of pressure as they are bigger.
200,000,000 billion degrees creates carbon. This is the temperature once stars run out
of hydrogen. Then they burn through the helium. That's when it stars moving much
Q: Where does it get 3 billion degrees?•
Big History Project - What did Stars give us?
Fusing carbon to neon -> oxygen -> silicon -> iron at 3,000,000 billion degrees.•
At iron all the elements scatter into the universe•
A: Exploding stars○
Large stars filled with iron explode in supernova - all the elements are created. For a
few weeks they shine brighter than whole galaxies.
Leaves a big dust cloud of all the elements drifting away
Q: Where do the rest (after iron_ come from?•
Wednesday, January 24, 2018 10:58 AM
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