Fusion

The combining of the nuclei of lighter elements to form heavier elements.

This is one method by which nuclear energy is produced.

Photosphere

The visible surface of the sun.

Chromosphere

The inner layer of the sun's atmosphere, located above the photosphere and below the corona.

Corona

The outermost layer of the sun's atmosphere,

located above the chromosphere.

Sunspot

Dark areas on the sun's photosphere that result from variations in the sun's magnetic field.

Solar wind

A constant stream of electrically charged particles that is blown out from the sun in all directions.

Aurora

A glow in the night sky produced in the upper atmosphere by particles from the solar wind interacting with Earth's magnetic field.

Geocentric

A model of the universe that has

Earth at the center.

Heliocentric

A model of the solar system that has the

sun at the center.

Gravitation

The force of attraction between

any 2 objects with mass.

Inner planets

The 4 planets closest to the sun.

Mercury, Venus, Mars, Earth,

Outer planets

The 4 planets farthest from the sun and

past the asteroid belt...

Jupiter, Saturn, Uranus, Neptune

Jovian Planets

Another term for the outer, gaseous planets.

Asteroid

A solid, rocklike mass that revolves around the sun.

Comet

A mass of rock, ice, dust and gas traveling

around the sun

and

usually in a highly eccentric orbit.

Meteor

The light made by a meteoroid as it passes

through the Earth's atmosphere.

Meteorite

The part of a large meteor that survives the trip through the Earth's atmosphere and strikes the Earth's surface.

Meteor shower

A large number of meteors entering and burning up in the atmosphere.

They take place when Earth passes through a debris field.