Democritus

Democritus () was an ancient Greek philosopher. He was born in Thrace, Greece, circa 460 BC.
He was a rich citizen of Abdera, in Thrace, and a student of Leucippus, another Greek philosopher. He studied natural philosophy in Thrace, Athens and Abdera. He liked to study geometry and he travelled to many places, including Egypt, Babylon and India. He wrote many books and never married.
Democritus is famous for his atomic theory of the universe. He said the universe is made up of two elementsː the atoms, and the space where they exist and move". He believed that all matter is made up of atoms. They are eternal, indestructible and invisible particles. They are made of different shapes, different properties and they are always moving. He believed the number of atoms is infinite.
Democritus didn't have any scientific evidence. He had these ideas thinking about them. However, his ideas were close to the discoveries made 2000 years after his death.
He died ca. 370 BC.