Chapter 8 Lesson 1 - Earth and Sun

rotation

A complete spin on the axis

gravity

A force of attraction, or pull, between any two objects.

orbit

A path one object takes around another object.

What causes the seasons on Earth?

As Earth revolves around the Sun, sunlight hits different parts of the Earth at different angles.

revolution

One complete trip around the Sun

Moon's gravity vs. Earth's

The Moon's gravity is 17% of Earth's gravity

mass

The amount of matter in an object.

perihelion

The closest that Earth gets to the Sun

aphelion

The farthest Earth can get from the Sun

axis

The imaginary line on which the earth rotates.

What causes day and night on Earth?

The rotation of the Earth on its axis

inertia

The tendency of a moving object to keep moving in a straight line.

What keeps the planets orbiting the sun?

gravity and inertia

factors that influence gravity

mass and distance

ellipse

the nearly circular orbit of the Earth is called an ____________.