Unit 7

One spin of an object on its axis. “Day”.

Imaginary line on which an object rotates.

One orbit of an object around its primary. “Year”.

The path an object makes as it revolves.

The object a satellite revolves around.

Any object that revolving planets and stars.

A model of the universe in which Earth is at the center of the revolving planets and stars.

A model of the solar system in which Earth and the other planets revolve around the sun.

A force that moves rocks and material downhill; the force that pulls objects toward each other.

The resistance an object has to change in its movement.

The average distance between the sun and earth. 1.496x10^8km or 1AU.

Study of space, including stars, planets, and other objects in space, and their origins.

Occurs when the moon passes between Earth and the sun, blocking the sun’s light from Earth.

Occurs when the moon passes through Earth’s shadow.

One of two days in the year when the hours of daylight equal the hours of darkness over Earth as a whole.

Region of total shadow.

Region of partial shadow.

One of two days in the year when hours of daylight and hours of darkness are at their greatest and least.

Tides that are least extreme; happen twice a month at first and last quarter moon phases.

Tides that are most extreme; occur twice a month at full and new moon phases.

The middle layer of the sun’s atmosphere.

The outer layer of the sun’s atmosphere.

Distance light travels in a vacuum in one year, equal to 9.46x10^12 kilometers.

The splitting of an atom’s nucleus into two smaller nuclei and neutrons.