Timeline: The most significant events in astronomy

200,000 BCE

The BIg Bang

Billion of years ago in the center of the Universe the Big Bang probably occurred.

2000 BCE

First solar-lunar calendars

2,000 B.C. in Egypt and Mesopotamia first solar-lunar calendars

280 BCE

The Earth around the sun

280 B.C. in Samos (Alexandria) Aristarchus suggests the Earth revolves around the Sun. He provides first estimation of Earth-Sun distance.

240 BCE

The circumference of the Earth

240 B.C. in Cyrene (now Shahhat, Libya) Eratosthenes measures the circumference of the earth with surprising accuracy

130 BCE

The first stars maps

130 B.C. in Greece Hipparchus develops the first acccurate star map and star catalogue with over 850 of the brightest stars.

45 BCE

Julian Calendar

45 B.C. in a Roman Empire Introduction of the Julian calendar, a purely solar calendar, to the Roman Empire

Sep 6, 1054

Supernova in Taurus

1054 A.D. in China, Chinese astronomers observe supernova in Taurus

Sep 6, 1120

Construction of an observatory in Cairo

1120 A.D. in Egypt Construction of an observatory in Cairo was begun in 1120 A.D. This is possibly the first observatory built in Medieval Islam. Unfortunately, the patron of the observatory was found guilty of several crimes including communication with Saturn, and was sentenced to death. The observatory was then destroyed in 1125 A.D. and the personnel were forced to flee for their lives.