Picture of Hipparchus
Hipparchus was a Greek astronomer who lived between 190-120 B.C. He created the first accurate star map and kept a catalogue of over 850 stars with their relative brightnesses. He also developed the system of epicycles (where everything in space moved in perfect circles) for the planets that both agreed with observation, and preserved the Earth-centered universe of Aristotle.
Hipparchus compiled a table of chord lengths, similar to modern trigonometry tables, and is considered the founder of trigonometry, a branch of mathematics which studies the angles of sides of triangles.
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable....more
Ptolemy was a Greek astronomer who lived between 85-165 A.D. He put together his own ideas with those of Aristotle and Hipparchus and formed the geocentric theory. This theory states that the Earth was...more
Aristotle was a Greek philosopher who lived between 384-322 B.C. He was one of the greatest thinkers of the world and his written works encompassed all major areas of thought. Aristotle mistakenly believed...more
Archimedes was a Greek mathematician and engineer who lived between 287-212 B.C. His greatest contributions are in the field of geometry and in the development of war machines. Legend has it that Archimedes...more
Democritus was a Greek philosopher who lived between 470-380 B.C. He developed the concept of the 'atom', Greek for 'indivisible'. Democritus believed that everything in the universe was made up of atoms,...more
Eratosthenes was a Greek scientist who lived from 276 to 194 B.C. He studied astronomy, geography, and math. Eratosthenes is famous for making the first good measurement of the size of the Earth. He spent...more
Plato was a Greek philosopher who lived between 427-327 B.C. He founded the Academy in Athens, a school which made many important scientific discoveries during ancient times. Although Plato made no important...more
Pythagoras was a Greek philosopher who lived between 580-520 B.C. He founded a school in Croton, which made outstanding contributions to the field of mathematics. Pythagoras and his cult members believed...more