Light speed

The speed of light is approximately 186,000 miles per second. This is how far light travels each second. A light year is how far light travels in a year.

Sun - facts 11

A solar flare is a large eruption in the Sun's atmosphere.

Meteor

A meteor is the visible path of a meteoroid that has entered the Earth's atmosphere and burns up.

Planets - facts 14

Planets do not give off their own light. They shine from the light of their star.

Planets - facts 13

Planets are round shaped because of gravity.

Planet

A planet is a round celestial body that revolves around a star. Planets are round because of gravity. A planet is illuminated by the light from its star.

Gravity

Gravity is the force of attraction between all masses in the Universe.

Dark matter

Dark matter makes up approximately 25% of the Universe. It is matter in the Universe that cannot be seen, but is detected by gravitational effects on other bodies.

Dark energy

Dark energy makes up over 70% of the Universe. Dark energy is believed to increase the rate of expansion of the Universe.