This is the layer of gases that surrounds our planet and is important for sustaining life.

This is the original source of nearly all energy on Earth.

The universe has been expanding ever since this event over 13 billion years ago.

This force that increases with mass keeps planets in orbit around their star.

This is a measurement of how quickly the particles in a substance are moving.

The "hydro" in Hydrosphere means this, which covers over 70% of Earths' surface.

Chemical energy stored in food is transformed into this kind of energy when used to move our bodies.

Our solar system is just a tiny speck in one of the arms of this galaxy.

The Earth orbits around the star Sol, making it a natural one of these.

Changing concentrations of carbon dioxide have contributed to this effect, which refers to trapping heat from the sun in our atmosphere.

Rocks, air, and water are all examples of this type of factor, which has never been alive.

Light and microwaves are both examples of energy being transferred over a far distance, also referred to as this.

You can find the Earth in one of these, a group of objects revolving around a star.

The Earth rotates around this invisible line with a 23.5° tilt.

A stone at the top of a tall cliff has this type of mechanically stored energy.

All organic material on Earth is a part of this sphere.

This is a measure of how much thermal energy is transferred between materials of different temperature.

It's theorized that one of these objects with unimaginable gravity is located at the center of our galaxy.

On this day, the Northern hemisphere is tilted directly toward the sun and receives more solar radiation than any other day of the year.

When the Moon and Sun form a right angle with the Earth, we get this type of tide with the narrowest tidal range.

This sphere contains mighty mountains and tiny particles of sand.

The sun's energy is produced through this process in which the nuclei of light elements combine to form heavier ones.

Our sun was at one point one of these clouds of dust and gas.

Two objects in orbit around each other are actually orbiting around this center of mass.

This planet experiences the most extreme temperature differences between night and day because it lacks an atmosphere.