ASTR 3 Lecture 1: Chapter 1: A Modern View of the Universe
3 pages116 viewsWinter 2019
Course CodeASTR 3
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What is Astronomy?
❖ Astronomy covers the structure and composition of the Universe from its beginning to its
➢ Where did your atoms come from?
➢ What is the Universe made of?
➢ What happens in 1 billion years?
➢ What happens in 100,000 billion years?
❖ Universe is vast, possibly infinite space, sparsely filled with hydrogen and helium gas
➢ Some places has gravity pull the gas together to make objects (Ex. you)
❖ Your atoms once drifted for more than a billion years in space
❖ Your atoms have been part of several stars including at least one supernova explosion
❖ The oceans will boil in 1 billion years
❖ The Chesapeake Bay was formed through the impact of an asteroid 35 million years ago
❖ At least 30% of stars have planets
❖ >1.1 billion in existing catalogs
❖ 90% fusing H into He like the sun
❖ Sun is in top 10% of brightest stars
❖ A few stars 1,00,000x more luminous than the sun, most 10,000x fainter
Our Solar System
❖ Solar system is basically the sun with some left-overs
➢ Sun is 99.85% of total mass
➢ 1000x more massive than Jupiter which is 2nd most massive object
➢ 330,000x more massive than Earth
Basic Properties of Sun
❖ Distance: 1.48x10^8 km = 1 A.U.
❖ Mass: 1.99x10^30 kg = 330,000 Earths
❖ Radius: 6.96x10^5 km = 100 Earth radii = 2x orbit of moon
❖ Red Giants, White dwarfs, Neutron stars
❖ All in some stage of death--often throwing material back to space
Giant Molecular Clouds
❖ 1,000 solar masses of dust and gas
❖ Debris from dead stars
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