Gravity

1. Gravity exists only on Earth.

Gravity also affects objects in space. In fact, objects stay in orbit because of gravity. Without gravity, a satellite launched from the Earth would simply drift off endlessly into space, traveling in a straight line, instead of circling the planet. Gravity pulls objects toward the center of the planet, causing them to accelerate and drop toward the planet.

2. Weight and mass are the same.

Weight and mass are not the same. Mass is a measure of a body's resistance to changes in its state of motion, which depends on the amount of matter it contains. Weight is the force of gravity exerted on a body due to its mass and its location near another, more massive object. An astronaut in space can be weightless but cannot be without mass.