Ch 2: Solar System Flashcards
Earth orbits the sun at average distance of
150 million km
Other planets extend out to or orbit at distances of
40 A.U.
The sun is a ____
with a radius of ____
with a mass of ____
aka ____
star, 700000km, 10^30kg, Sols/Helios
The sun’s total energy output is ____, but only ____ reaches earth. Max is ____
3.8x10^26, 1.8x10^17, 1370 W/m^2
The amount of energy depends on
Angle of incidence
Does the sun’s behavior vary over time.
Yes. Sunspot cycle: 11 years
Sunspots:
dark patches formed by turbulence within the sun. Associated with magnetic storms on Earth
Sources of Solar Energy
Nuclear fusion of hydrogen to make helium
Spectroanalysis
determines surface composition, we can only infer whats below the surface.
SOHO
uses soundwaves from sun to determine whats under the surface
Most solar energy is output as ____
EMR: radio waves, IR, visible light, UV, x-ray, gamma rays.
Most solar energy are:
what does it include
short-wave, 10^-5 –> 10^-7,
radio waves, IR, visible light, UV
Milankovitch Cycles
Affect the distribution of solar energy over Earth’s surface. Affects climate: global totals, seasons. Involves eccentricity, axial tilt.
Eccentricity
100,000 year period, currently mid-way between most circular and most elliptical
High Eccentricity:
more elliptical
Low Eccentricity
more circular
Axial Tilt
Tilt creates seasons, 41,000 year period. Tilt varies from 21.5 to 24.5. The moon may have some effect on axial tilt. Gravitational pull of the moon
Precession of equinoxes
wobble of axis. The tilt direction rotates relative to elliptical orbit. Changes the position of the solstices and equinoxes.
Solstice:
tilted towards/away from the sun
Equinox:
tilted in parallel with the sun
Planet originally meant
wandering star. Planets undergo retrograde movement.
Visibile planets include:
mercury, venus, mars, Jupiter. Saturn
Visible planets via telescope include:
Uranus, Neptune, Pluto
Terrestrial Planets include:
mercury, venus, Earth, mars
Terrestrial Planets characteristics
Similar size and probable structure: rocky crust, denser rocky mantle, metallic core.
Jovian Planets include:
Jupiter, Saturn, Uranus, Neptune
Jovian Planets characteristics:
Thick hydrogen-rich atmosphere, liquid hydrogen interior, denser rock core
Molecular Hydrogen
normal hydrogen
Metallic hydrogen
forms a defined crystal lattice, behaves like a metal under extreme pressure, superhot liquid metal.
Dwarf Planets include:
Pluto, Ceres, Makemake, Haumea, Eris.
Physical Laws: Gravity
planets are maintained in orbit by gravitational force, varies with distance. F proportional to 1/d^2
Physical Laws: Shape of orbits
elliptical shape: sun at one focus of the ellipse.
Kepler’s First Law:
“Law of the Ellipses”
Physical Laws: Speed of travel
Speed varies: faster when closer
Kepler’s Second Law:
“Equal Areas”
Physical Laws: Orbit Periods
period is related to average distance. p^2 = kd^3
Kepler’s Third Law:
“Orbital Harmony”
Comets
small bodies in highly elliptical orbits. Similar to Jovian planets, samples of early solar system, Kniper belt, Oort cloud, Jupiter steers comets from inner planets. Icy and dusty compared to asteroids
Asteroids and Meteors
small body of variable composition. Rock, metallic ion..
Asteroids:
Meteors:
Meteorites:
in space
in atmosphere
on the ground
The BIG BANG
about 13.7 billion years (Ga) ago
Hubble’s Law:
age of universe is back calculation of the rate of expansion
Nebula Hypothesis
spinning cloud of dust and gas formed the sun and the planets
