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EPSC 201 Study Guide - Final Guide: Oceanic Crust, Oceanic Trench, Subduction


Department
Earth & Planetary Sciences
Course Code
EPSC 201
Professor
Anthony Williams- Jones
Study Guide
Final

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EPSC201 2006 Final Exam Review Section 1&2
1) Describe the first three minutes of the history of the Universe.
At the beginning stages of the universe, energy and mass were constantly changing back and for, via
E=mc^2. Once the universe had expanded, and therefore cooled down, matter become much more
dominant, than in the early stages. As the universe cools, larger particles are made. Three minutes in; at
this point, protons and neutrons are starting collide. There are heavier elements, combinations of
neutrons and protons and electrons, being formed.
2) What is the Hubble Constant? How would you use it to determine the age of the
Universe?
Hubble – asked questions such as: How old is the universe? How fast is it expanding? Will the universe
eventually stop expanding and start contracting?
Hubble determined our distance from other stars using luminosity of stars. The further a star is, the less
luminous is. He used the red shift to determine how fast the stars were moving away from us. He used
relative luminosities by comparing different stars. Had to assume every star was the same brightness and
speed was constant. He also used groups of stars to account for the fact that their brightness is NOT
constant.
Using Velocity = Distance / time Hubble was able to predict the age of the universe. He calculated that it
was 13.4 billion years old. Current models suggest it is actually 14.67 billion years old – Hubble was very
close.
3) Describe and explain the end stages of stellar evolution.
Our star was made roughly three and a half billion years ago, and has roughly the same time to live. Our
star is middle aged. It is also a 2nd or 3rd generation star. It is in equilibrium where gravity is pulling it
together, and fusion is exploding it outward. It’s composition is much different then a 1st generation star,
which are much older. The material in the outside of the star has an easier time to overcome gravity and
explode outward to become a red giant when nuclear fusion starts to consume most of the hydrogen (3-4
billion years in the future)
Big stars – shorter lifetime
Blue star – 40000 K (think blue wavelength = higher in energy = hotter)
Red star – much cooler (red wavelength = shorter wavelength – lower in E = colder)
Proto star – on the verge of becoming a star and burn hydrogen.
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