Chapter 2

The Solar System

Observing the Solar System

• Planets: “Wandering Star”

• Greeks Ideas: We lived in a Geocentric system. (Earth is in the center of solar system)

Copernicus’s Idea

• 1500’s

• Heliocentric System – Earth and other planets revolve around the sun.

• Galileo used telescope to prove heliocentric system idea.

Brahe and Kepler’s Law

• Orbit of each planet is an ellipse.

Issac Newton

• Inertia and gravity keep planets in orbit.– Inertia – a moving object continues in a straight

line .– Gravity – keeps planet in an orbit

The Sun

• Interior of the sun1. Nuclear fusion of H-

sun’s energy comes from

2. 5 billion years of fuel left

Sun’s Atmosphere

• 3 layers:• 3. Photosphere: inner

layer, light comes from

• 2. Chromosphere – reddish glow seen during an eclipse

• 6. Corona - outermost

Solar Wind

• Corona sends out stream of charged particles

• Creates Auroras (Aurora Borealis)

Antarctica:

Features of the sun

• Sunspots – dark spots on sun, areas of gas that are cooler than the rest of the sun.

Prominences

• Reddish loops of gas link sunspot regions

Solar Flares

• Explosions due to prominences connecting

• Increase solar wind – magnetic storms

Other objects in Solar System

• Comets: “dirty snowball”

• Orbits are long and narrow

• 3 parts of a comet: – Tail –

– Nucleus –

– Coma -

Orbit of a comet

Asteroids

• Too small to be planets

• Belt between Mars and Jupiter

• Discovered about 10,000 asteroids

• Impact Yucatan Peninsula, Mexico

                                              

Meteors

. Meteoroid: chunk of rock or dust in space.

• Meteor: A streak of light in the sky produced by the burning of a meteoroid in Earth’s atmosphere

• Meteorites: meteoroids that pass through the Earth’s atmosphere and hit the Earth’s surfaceMeteor crater in Arizona

A bright meteor 1998 , Florida