Kepler's Laws

Orbits happen because of gravity and something called momentum. The Moon's momentum wants to carry it off into space in a straight line. The Earth's gravity pulls the Moon back towards the Earth. The constant tug of war between these forces creates a curved path. The Moon orbits the Earth because the gravity and momentum balance out.

Johannes was born in Weil der Stadt (now part of Germany). He had an interest in astronomy from a very young age. When he was 6, his mother took him up to a high place to see the Great Comet of 1577. When he was 9, he was called outdoors to see a lunar eclipse. His family were poor, but Johannes got a scholarship to study at the University of Tübingen.