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Lecture 1

ASTR 3 Lecture 1: Chapter 1: A Modern View of the Universe

3 pages116 viewsWinter 2019

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What is Astronomy?
Astronomy covers the structure and composition of the Universe from its beginning to its
ultimate end
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)
Fun Facts
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
Rare Stars
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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