-
276 BCE
Eratosthenes
Discovered in 255 BC- measured Earth's circumference mathematically using two surface points to make the calculation.
Important- the circumference of the earth was about 50 times greater than the distance from Alexandria to Aswan. -
194 BCE
Eratosthenes
Died -
100
Claudius Ptolemy
Discovered in March 16, 127- record longitudes and latitudes in degrees for roughly 8,000 locations on his world map Important- astronomers could accurately predict eclipses and the positions of planets. -
170
Claudius Ptolemy
Died -
Feb 19, 1473
Nicolaus Copernicus
Discovered in 1508 -The theory that the Sun is at rest near the center of the Universe, and that the Earth, spinning on its axis once daily, revolves annually around the Sun. Important-that Earth and other planets revolve around the sun, -
May 24, 1543
Nicolaus Copernicus
Died -
Dec 14, 1546
Tycho Brahe
Discovered in 1572- C/1590 E1
Important: It showed that it was farther away than the Moon and was among the fixed stars, which were regarded as perfect and unchanging. -
Dec 27, 1571
Johannes Kepler
Discovered in 1609- that the orbit of Mars was an ellipse
Important- planets move proportionally faster in their orbits when they are closer to the Sun -
Tycho Brahe
Died -
Johannes Kepler
Died -
Sir Isaac Newton
Discovered in 1665 or 1666 - the gravitational force
Important - proposed that all objects in the Universe pulled on each other through gravity. -
Sir Issac Newton
Died -
Albert Einstein
Discovered in 1915 the theory of relativity Important- he predicted black holes and gravitational waves -
Albert Einstein
Died