1	Exploration of Space E - 1 From the Sun to the Earth Chapter 1 - 1
2	Solar System The sun is the center of the Solar System
3	Sun The suns shell is composed mostly of hydrogen and helium and is a giant thermonuclear reactor
4	Structure of Sun 864,000 mile diameter compared to 8,000 miles of Earth’s diameter
5	Structure of Sun Sun’s magnetic field is 100 times greater than that of the Earth’s
6	Terrestrial Planets Terrestrial Planets make up inner solar system Mercury Venus Earth Mars
7	Mercury Smaller then any other planet except Pluto Most elliptical orbit except Pluto
8	Mercury Only spacecraft to visit Mercury was the Mariner 10 in 1974-75
9	Venus 2nd planet out from the sun Earth’s closest planetary neighbor in distance & size
10	Venus Rotates in a direction opposite that of Earth and most other planets
11	Earth 3rd planet from the sun 5th largest in solar system only planet that can sustain life
12	Northern Lights Aurora Borealis are emissions from polar magnetic storms and appear as lights in extreme northern latitudes at night
13	Cislunar Space Space between Earth and moon Average distance between the Earth and moon is 232,043 miles
14	Meteoroids Clumps of matter in space that are drawn by the Earth’s gravitational force and enter the outer fringes of the Earth’s atmosphere
15	Meteor Meteoroids that enter the Earth’s atmosphere can be seen at night as a “shooting star” usually burn out
16	Meteorite Meteors that get through the Earth’s atmosphere and lands on Earth