Lecture 3- Origin of Stars, Earth, Moon & Oceans Flashcards
1
Q
What generation is our sun?
A
3rd generation
2
Q
What element existed in the universe when it was created?
A
hydrogen
3
Q
What happens when stars explode?
A
heavier elements (after iron) form
4
Q
When did the Big Bang occur?
A
about 15 billion years ago
5
Q
compressional heating
A
- causes temperatures in the core of large masses to increase
- when the temperature reaches 10 million Kelvin, nuclear fusion of H to He is ignited to form heat and visible light
6
Q
terrestrial (inner) planets
A
- relatively small
- rocky shell over metallic core
- accretion began 4.6 billion years ago
7
Q
gaseous (outer) planets
A
- mostly volatile gases (H, He)
- same composition as the sun
8
Q
How old is the sun?
A
4.5 billion years (currently at midlife)
9
Q
What will happen to the sun in 4 billion years?
A
- run out of hydrogen fuel and die
- before it dies, it will expand beyond the orbit of earth and vaporize earth
- vaporized atoms will contract back and form new stars and planets
10
Q
How old is the earth?
A
About 4.6 billion years
11
Q
formation of the moon
A
- the moon was formed when earth was hit by a Mar-sized object (“Thea”)
- gave us the tilt, moon, seasons and tide
12
Q
early Earth
A
- atmosphere consisted of hydrogen and helium
- anaerobic (no oxygen)
- no carbon dioxide or water (very cold)
13
Q
modern Earth
A
- out-gassing from volcanoes released H2O and CO2
- photosynthetic life then evolved and produced modern O2 rich atmosphere
14
Q
theories of the origin of water
A
- water formed in place and later out-gassed and condensed
- from comets
- from asteroids
15
Q
5 Oceans
A
- Atlantic
- Pacific
- Indian
- Southern
- Arctic
