Earth and Space Science - Ch. 4 Vocabulary

Epicycle/Retrograde Motion

Erratic paths seen for some planets due to errors in geocentric solar system model

Geocentric Model

The solar system model that has the earth at the center of the solar system

Heliocentric Model

The solar system model that has the sun at the center of the solar system

Inner Planets

Mercury, Venus, Earth, Mars

Outer Planets

Jupiter, Saturn, Uranus, Neptune

Volatiles

Materials that evaporate quickly at typical earth temperatures and pressures

Spectroscopic Measurement

Measurement of wavelengths of light given off by an object

Nebula

A cloud of dust, ice, and gas in space

Comet

An icy, small solar system body that warms and begins to release gas when it passes close to the sun.

Revolve

To orbit around an object

Gravity

the natural attraction between physical bodies due to their masses.

Protostellar Disk

The flattened cloud formed by a collapsing nebula

Fusion

Combining two or more nuclei to make a new atom

Matter

Any substance that has mass and takes up space

Solar Wind

A stream of charged particles streaming from the sun

Terrestrial Planets

Mercury, Venus, Earth, Mars

Impact Crater

Surface depression due to being hit 

Meteorites

An object from space that hits the surface

Asteroid

A small orbiting object

Light Year

A distance measurement, constant anywhere in the universe

Orbit

A closed looped path

Ellipse

An oval

Parallax

The apparent shift of an object with respect to the background

Transit

One planet passing in front of another

Spring Tides

Strong tides that occur when the sun and moon are in line

Neap Tides

Weak tides that occur when the sun and moon are perpendicular

Albedo

The fraction of radiation that is reflected

Greenhouse Gases

part of the atmosphere that absorb and give off infrared radiation

Water Cycle

Water changing phases driven by energy from the sun

Earth’s Tilt in Degrees

About 23 degrees off vertical

Solstice

When the sun is farthest north or south, the longest or shortest day of the year

Equinox

When the sun is directly over the equator, commonly called equal length day and night

Sunspots

Darker spots on the sun’s surface

Precession

A change in rotation

Glacier Erratic

Rocks from far away left out of place as ice sheets melted

Insolation

Milankovitch’s increasing and decreasing amounts of solar radiation related to earth’s glacier cycle