| Geology (GEL-120) |
[Jan. 25th, 2008|09:49 am] |
| [ | Tags | | | big bang, cosmology, differentiation, earth, fe, gas giants, gel-120, geocentric, geology, heliocentric, kant's solar nebula theory, magnetic field, nebulae, proto planets, scientific method, solar wind, stellar nucleosynthesis, terrestrial, theory | ] |
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Scientific Method
Theory => model
1- predictions
2- supported by body of evidence
Cosmology - formation of the universe
geocentric - earth is the center
heliocentric - sun is the center
SUN --> [Terrestrial Planets: Mercury, Venus, Earth, Mars] (Belt) [Gas Giants: Jupiter, Saturn, Uranus, Neptune, Pluto]
**BIG BANG**
(small pt (no mass or volume) -> large pt)
1- expanding universe
2- blue light shift/red light shift
3- doppler effect
Nebulae - patchy clouds of gas sepparated from one another by the vacuum of space.
Kant's Solar Nebula Theory -
1- planets in plane of the ecliptic
2- distribution of matter
3- all planets revolve around in the same direction
Solar Nebula:
- distribution of mass
- disc shape
- planets in the plane of ecliptic
- planets revolve around sun in same direction
- planets rotate in same direction (except Venus)
Proto Planets/Planetisimals
- forming through acreation
- heat of acretion causes melting
- differentiation occured to form layers in early Earth
- core consists of iron FeN
- outer core = liquid Fe magnetic field
Stellar nucleosynthesis
1- fusion
2- neutron capture & decay
Differentiation - layered structure of Earth
- most Greek philosophers favored a geocentric Universe concept.
- The Renaissance brought a revolution in scientific thought.
- Eratosthenes was able to measure the size of the Earth in ancient times, but it was not until fairly recently that astronomers accurately determined the distance to the Sun, planets, and stars.
- The Earth is one of nine planets orbiting the Sun, and this solar system lies on the outer edge of a slowly revolving galaxy, the Milky Way, which is composed of about 300 billion stars.
- The red shift of light from distant galaxies, a manifestation of the Doppler effect, indicates that all distant galaxies are moving away from the Earth.
- The first atoms (H & He) of the Universe developed about 1 million years after the Big Bang.
- According to the nebular theory of planet formation, gravity causes clumps of gas in the nebulae to coalesce into revolving balls.
- Heavier elements form during fusion reactions in stars.
- Planets developed from the rings of gas and "dust", the planetary nebulae, that surrounded protostars.
- The Moon formed from debris blasted free from Earth when our planet collided with a Mars-sized planet early during the history of the solar system.
- A planet the size of the Moon or larger will assume a near-spherical shape because the warm rock inside is so soft that gravity can smooth out irregularities.
Earth:
Crust, Outer Core (liquid Fe alloy), Inner Core (solid FeNi alloy)
- Earth has a magnetic field, which shields it from solar wind.
Magnetic Field: the region affected by the force emanating from a magnet
Solar Wind: particles ejected from the Sun consist predominantly of protons and electrons and constitute the wind which blows across the full width of the solar system at speeds of up to 400 km/s
- a layer of gas surrounds the Earth
- the surface of the Earth can be divided into land and ocean.
- the Earth consists of organic chemicals, minerals, glasses, rocks, metals, melts, and volatiles.
- the Earth's interior can be divided into 3 compositionally distinct layers crust, mantle, & core.
- pressure and temperature both rease wtih epth in the Earth.
- studies of seismic waves have revealed the existence of sublayers in core and mantle.
- the crust is a thin skin that varies in thickness from 7-10 km to 25-70 km.
- the crust plus the upper part of the mantle constitute the lithosphere, a relatively rigid shell. |
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