Probably the first astronomers. Measured time using sundials and water clocks. Believed the Earth was flat with a dome shaped sky. Studied astronomy to try and predict future events.

Hot air rises to reach the sphere of Fire, so heated balloons go up. Elements had a natural tendency to separate in space; fire moved outwards, away from the earth, and earth moved inwards, with air and water being intermediate. Thus, each of these five elements occupied a unique place in the heavens (earth elements were heavy and, therefore, low; fire elements were light and located up high). All planets revolve around the Earth.

Made thousands of measurements and catalogues over 850 stars.

Thought that the Earth was round because: The stars don’t rise and set in the same place everywhere. An eclipse is seen at different times in different parts of the world. Some stars can be seen in the north but not south. A ship sailing over the horizon doesn’t just get smaller- the bottom disappears first and the mast last.

Thought that stars were fixed to a sphere which rotated to make them move. Thought everything surrounded the Earth. His work was considered to be against religion and many of his books were burnt.

Thought that the Sun was the centre of the universe and that everything revolved around it.

Invented the telescope. Found that two objects of the same shape but with different masses are dropped they will fall at the same speed – acceleration of free fall.

Described the movement of the planets with his laws of motion. Motion of the planets was explained with his theory of gravity. Suggested that the Earth’s gravity caused the moons orbit.

As a child, Sommerville was banned from studying science. The term ‘scientist’ was first coined in a review of her work. Predicted that there was an undiscovered planet behind Uranus… Neptune was discovered twelve years later.

Einstein couldn’t talk until he was three. He was expelled from school for being disruptive. Showed that time does not pass at the same speed everywhere. Predicted the existence of black holes. Said that a rocket travelling at the speed of light will have a higher mass than one not moving.

Suggested that our galaxy is one of billions and that the universe is expanding. The Hubble telescope is named after him. Einstein had calculated that the universe was either expanding or contracting in 1917, but refused to believe his own predictions.