What Is an Orbit

Planets in our solar system do not move in straight lines. Instead, they follow curved paths called orbits around the Sun. An orbit is the path an object takes as it moves around another object in space. For example, Earth orbits the Sun once every year.

The main force that keeps planets in their orbits is gravity. Gravity is a force that pulls objects toward each other. The Sun is much bigger and heavier than any of the planets. Because of this, its gravity is very strong and pulls the planets toward it. But the planets are also moving forward, so they do not fall straight into the Sun.

This movement is explained by another idea called inertia. Inertia means that an object wants to keep moving the same way unless something stops it. The planets want to go in a straight line, but the Sun's gravity pulls them in. The combination of gravity and inertia causes the planets to move in curved orbits instead of flying off into space or crashing into the Sun.

Other objects in space also orbit. The Moon orbits Earth, and satellites orbit our planet to help us with weather, communication, and science. Even the International Space Station orbits Earth, allowing astronauts to live and work in space.

The shape of a planet's orbit is usually like an oval, called an ellipse. Most planets have orbits that are almost circles, but some are more stretched out. Orbits help keep our solar system in order, making sure planets and other objects move safely and regularly.

Interesting Fact: The planet Mercury has the fastest orbit around the Sun, taking only 88 days to complete one trip!