Astronomers of history

Claudius Ptolemy 100-170

150

Claudius Ptolemy was a 2nd century Greek mathematician, astronomer and geographer famous for his controversial geocentric theory of the universe, which would form the basis of our understanding of the motions of stars and planets for over than a thousand years.

Nicolaus Copernicus 1473-1543

1473

Nicolaus Copernicus was an astronomer who proposed a heliocentric system, that the planets orbit around the Sun; that Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow changes in the direction of this axis account for the precession of the equinoxes.

Johannes Kepler 1571-1630

1530

Johannes Kepler was a German mathematician and astronomer who discovered that the Earth and planets travel about the sun in elliptical orbits. He gave three fundamental laws of planetary motion. He also did important work in optics and geometry.

Tycho Brahe 1546-1601

1572

Tycho Brahe made accurate observations of the stars and planets. His study of the “new star” that appeared in 1572 showed that it was farther away than the Moon and was among the fixed stars, which were regarded as perfect and unchanging. In 1572, Tycho observed and recorded a supernova

Galileo 1564-1642

1632

Galileo supported the idea that the sun was at the center of the universe, an idea that was proposed by Nicolaus Copernicus. He was sentenced to life in prison for challenging the common believe the the earth was the center of the universe. It was declared this theory as heresy by the Catholic Church because it was viewed as contradicting certain Bible verses. But later was put on house arrest and spent the rest of his life there.

Sir. Isaac Newton 1643-1727

1700

Although Isaac Newton is well known for his discoveries in optics (white light composition) and mathematics (calculus), it is his formulation of the three laws of motion—the basic principles of modern physics—for which he is most famous. Isaac Newton changed the way we understand the Universe. Revered in his own lifetime, he discovered the laws of gravity and motion and invented calculus.

Edmond Halley 1659-1742

1716

Halley is famous in his own right for analyzing the orbits of comets, which he showed to be elliptical and periodic. Halley's Comet returned, as he predicted, in 1758, 15 years after his death. (The comet last appeared in 1986, and next will appear in 2061.) In 1716 he devised a method for observing transits of Venus across the disk of the Sun, predicted for 1761 and 1769, in order to determine accurately, by solar parallax, the distance of Earth from the Sun.

William Herschel 1738-1822

1758

Sir William Herschel was a German-born British astronomer and composer, who is widely credited as the founder of sidereal astronomy for observing the heavenly bodies. He found the planet Uranus and its two moons, and formulated a theory of stellar evolution. Herschel was one of the first 'professional' astronomers, and discovered infrared radiation. His sister Caroline helped him to develop the modern mathematical approach to astronomy.

Edwin Hubble 1889-1953

1924

Edwin Hubble, for whom the Hubble Space Telescope is named, was one of the leading astronomers of the twentieth century. His discovery in the 1920s that countless galaxies exist beyond our own Milky Way galaxy revolutionized our understanding of the universe and our place within it.

Carl Sagan 1934-1996

1976

Carl Sagan was one of the most well-known scientists of the 1970s and 1980s. He studied extraterrestrial intelligence, advocated for nuclear disarmament and co-wrote and hosted 'Cosmos: A Personal Voyage. He believed that if all those countless stars are suns, they might have their own planets. The universe could be teeming with life. The idea was delectable. Sagan also learned about a powerful method, called science, that could help him explore such ideas.