Seleucus (or Seleukos) of Seleucia (born circa 190 BC - ?) was a Greek astronomer.

He born in Seleucia on the Tigris in Babylonia. Teaching around 150 BC, he agreed with the heliocentric theory of Aristarchus of Samos, which stated that the Earth rotated around its own axis which in turn revolved around the Sun (we do not know other names of ancient astronomers or scientists who suppoorted the heliocentric system: Hipparchus and later Ptolemy contributed to the success of the geocentric system; however, in the writings of Plutarch and Sextus Empiricus we read of "the followers of Aristarchus", thus it is probable that other people we do not know of adhered to the heliocentric view). According to Plutarch Seleucus even proved the heliocentric system. We ignore his arguments, but probably were related to the phenomenon of tides. Indeed Seleucus correctly theorized that tides were caused by the Moon, although he believed that the interaction was mediated by the Earth's atmosphere. He noted that the tides varied in time and strength in different parts of the world.

Seleucus is known from the writings of Plutarch.

Greek philosophers | Greek and Roman astronomers

Seleukos von Seleukia | Seleuco di Seleucia | Selevk | Селевк (астроном)