Johannes Kepler

By Amy

Johannes Kepler's 3 planetary laws

When Johannes Kepler was born, scientists believed that the planets travelled around Earth in circular orbits. But in 1605 Kepler found out that the planets orbit the sun and they travelled in ellipses (stretched out circles/ovals.) that was the first law.

Kepler also discovered that the closer the planet was to the sun, the faster it would move and when it was further away from the sun, it would move slower. This was his second law which was made in 1609.

Kepler's third law was made in 1618 and it shows that planets take different amounts of time to orbit the sun, depending on their distance from the sun.

Other discoveries

Kepler was the first to understand how the eye works and he made eyeglasses ( reading glasses ) for near and farsighted people. He understood how both eyes were needed to see depth and he was the first one to explain how a telescope worked.

Kepler learned about gravity and discovered that tides were caused by the moon.

He also calculated the birth year of Christ.

Kepler learned that the lenses in our eyes invert, ( turn upside down ), the images that we see. It is then the brain that corrects these images for us. Using the knowledge of our eyes work, Kepler was able to improve the telescope in 1611 by adding to convex lenses which allowed greater magnifications.


The more we understand about the movement of the planets and the sun, the better we can decide whether it is possible for any life to survive on them.