Lecture 3- Origin of Stars, Earth, Moon & Oceans Flashcards
What generation is our sun?
3rd generation
What element existed in the universe when it was created?
hydrogen
What happens when stars explode?
heavier elements (after iron) form
When did the Big Bang occur?
about 15 billion years ago
compressional heating
- 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
terrestrial (inner) planets
- relatively small
- rocky shell over metallic core
- accretion began 4.6 billion years ago
gaseous (outer) planets
- mostly volatile gases (H, He)
- same composition as the sun
How old is the sun?
4.5 billion years (currently at midlife)
What will happen to the sun in 4 billion years?
- 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
How old is the earth?
About 4.6 billion years
formation of the moon
- the moon was formed when earth was hit by a Mar-sized object (“Thea”)
- gave us the tilt, moon, seasons and tide
early Earth
- atmosphere consisted of hydrogen and helium
- anaerobic (no oxygen)
- no carbon dioxide or water (very cold)
modern Earth
- out-gassing from volcanoes released H2O and CO2
- photosynthetic life then evolved and produced modern O2 rich atmosphere
theories of the origin of water
- water formed in place and later out-gassed and condensed
- from comets
- from asteroids
5 Oceans
- Atlantic
- Pacific
- Indian
- Southern
- Arctic
average depth of the ocean
4 km
latitude
degree of the angle from the equator
longitude
degree of the angle from the Prime Meridian (Greenwich)
near 0 degrees longitude
Atlantic Ocean
approaching 180 degrees longitude
Pacific Ocean
