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 at the center of the universe and all other heavenly bodies circled it, a model which held for 1400 years until the time of Copernicu

276-197 B.C.

Eratosthenes is most famous for making the first good measurement of the size of Earth. He did that sometime around 240 B.C. He knew that there was no shadow at the bottom of a well in the town of Syene on the summer solstice.

1473-1543 A.D.

Copernicus changed this belief when he introduced the heliocentric model, centered around the sun. He claimed that all the planets, including Earth, moved in orbits around the sun, and showed how this new system could accurately calculate the positions of the planets.

1546-1601 A.D.

For over twenty years, he made very accurate observations of the night sky, all without the aid of a telescope, which had not yet been invented. Tycho also built the world's first observatory and kept a star catalogue with over 1000 stars.

1564-1642 A.D.

Galileo was the first person to use a telescope to look at the heavens. He discovered sunspots, and craters and peaks in the moon. Galileo's work offended the Roman Catholic Church and he was sentenced to house arrest for the later years of his life. Today, he is remembered as a martyr for scientific truth.

1564-1642 A.D.

Galileo was the first person to use a telescope to look at the heavens. He discovered sunspots, and craters and peaks in the moon. Galileo's work offended the Roman Catholic Church and he was sentenced to house arrest for the later years of his life. Today, he is remembered as a martyr for scientific truth.

1564-1642 A.D.

Galileo was the first person to use a telescope to look at the heavens. He discovered sunspots, and craters and peaks in the moon. Galileo's work offended the Roman Catholic Church and he was sentenced to house arrest for the later years of his life. Today, he is remembered as a martyr for scientific truth.

1564-1642 A.D.

Galileo was the first person to use a telescope to look at the heavens. He discovered sunspots, and craters and peaks in the moon. Galileo's work offended the Roman Catholic Church and he was sentenced to house arrest for the later years of his life. Today, he is remembered as a martyr for scientific truth.

1642-1727 A.D.

He had one of the most brilliant minds the world has ever known. Legend has it that seeing an apple fall gave Newton the idea that gravity, the force which keeps us bound to the Earth, also controls the motion of planets and stars.

1656-1742 A.D.

Using historical records, his own observations, and Newton's universal law of gravitation, he reasoned that the comets which had appeared in 1456, 1531, 1607, and 1682, were one and the same. He then predicted the comet's return about every 76 years. Although Halley died in 1742, the comet reappeared 16 years later, and today bears his name

Caroline Herschel

1738-1822 A.D.

1750-1848

-She discovered three new nebulae in 1783. She also discovered eight comets between 1786-1797. In addition, she published two astronomical catalogues which are still used today.

-Herschel discovered the planet Uranus and advanced our understanding of nebulae, the hazy clouds that surround dying stars. He also founded stellar astronomy, the study of the region beyond our own solar system.

1803-1853 A.D.

He is known for the principle he first proposed in Concerning the coloured light of double stars in 1842. This principle is now known as the Doppler Effect. He hypothesised that the pitch of a sound would change if the source of the sound was moving