Did the ancient Greeks look up at the night sky and ask “are we alone?” As it turns out, ancient Greek philosophers also asked this existential question. One such philosopher, Anaxagoras, proposed that alien life might exist on the moon.
Most people in ancient Greece turned to religion to explain the stars, planets, and the other elements of the cosmos. For example, most Greeks in antiquity believed that the sun’s position in the sky was determined by the solar god Helios and his path across the sky in his horse-drawn chariot.
However, some ancient Greek philosophers like Anaxagoras stopped to ponder the workings of the universe in more scientific terms.
Anaxagoras’ theory about the moon and aliens
Anaxagoras, an ancient Greek philosopher who lived between 500 BC and 428 BC, attracted both fame and notoriety during his lifetime for his astronomical theories.
The philosopher, who was born in the ancient Greek polis (city) of Klazomenai in Asia Minor, theorized that the Moon is a great rock and the Sun a fiery mass of red-hot metal. He also suggested that the other stars, like the sun, are burning hot rocks.
Although Anaxagoras incorrectly believed that the Earth was flat, he was the first to correctly explain the phenomenon of eclipses.
The Greek philosopher also had some thoughts about aliens. Anaxagoras proposed the theory that extraterrestrial life existed on the Moon, possibly on its mountains.
Exile
Anaxagoras’ views on celestial objects and extraterrestrial life proved highly controversial. They contradicted the dominant religious beliefs and views espoused by other philosophers.
According to many versions of Greek mythology, the Moon was personified as the goddess Selene, who visited the Earth according to the lunar cycle. This religious view was contradicted by Anaxagoras’ theory; that the Moon was a rocky physical body possibly inhabited by aliens.
By modern standards, Anaxagoras is recognized as a brilliant scientist and philosopher, but back then his theories earned him the ire of the Athenian state, where he lived. In fact, he was charged with impiety and forced into exile. Even though his close friend, the infamous Greek politician and general Pericles, testified in his defense at the trial, it was not enough to save him from exile.
Ancient Greek theories about the cosmos
Anaxagoras was not the only ancient Greek philosopher who attempted to understand astronomy, despite the dominant religious views of the time.
Democritus, a philosopher from Abdera who lived between 460 BC and 370 BC, proposed that the universe contained an infinite number of worlds. This contradicted the later views of Plato and Aristotle that Earth was the only planet and the universe was much smaller than envisioned by Democritus.
Democritus’ theory caught on with later philosophers who followed in his footsteps. Epicurus, who was born in Samos in 341 BC, once wrote a letter to the historian Herodotus outlining his belief that “there is an unlimited number of cosmoi, and some are similar to this one and some are dissimilar.”