The Milky Way; two theories

Since watching the launch and docking of the Dragon spacecraft, I’m in a space mood. So today, on our virtual journey, I’m going to take you to an unlikely place: we’re going to go out to space, gaze at the Milky Way and speculate on how it got its odd name.

MilkyWay, Euboia, Dirfys

The Milky Way as seen from Mt. Dirfys, on the island of Euboia, Greece.


The myth

The Greek word Galaxy means “milky” or, more liberately transalted “Milky way”. To Greeks, the milky-white band streaking across the night sky was nothing sort of proof of the immensity and power of their gods.

It all started with the birth of Herclules, one of Zeus’s illegitimate children, and by far his favourite. Conceived by a mortal woman, Hercules was a mere demi-god. In order to make him immortal, Zeus took him from his cot one night and placed him next to his sleeping wife, Hera, so that he would suckle some of her divine milk. Hera woke and hastily pulled her breast out of the baby’s hungry mouth; her milk spilled all over the sky, creating the Milky Way.

To most Greeks this explanation may have seemed enough. However, there were always those with a propensity for asking difficult questions and trying to figure things out using reason, rather than relying on myths and traditions. One of them was called Democritus.

The philosopher

The well-travelled and eternally curious philosopher claimed that he preferred finding an explanation to becoming king of Persia (the mightiest empire known to Greeks at the time). Always cheerful and ready to laugh at human follies, he believed there were two kinds of knowledge, a lower one, obtained by the senses and a higher one, reached by reasoning. He made good use of his own, reaching some surprisingly accurate conclusions.


Bronze bust, probably showing Democritus. Roman copy of an original from the 3rd century BCE. Museo archeologico nazionale, Napoli, Italy


Democritus theorized that all matter consists of various tiny bodies he called atoms, which join together to form everything that exists in the universe. He proposed that the universe began as a formless soup of atoms churning in chaos. As they collided, they started forming larger bodies, among which the earth and all living things on it. Against the established beliefs of the time, he didn’t hold the earth as the centre of the universe nor did he think that celestial bodies were eternal and incorruptible. On the contrary, he believed that there are many worlds, each with a beginning and an end. Therefore, some of these had to be in a growth stage and others declining. He thought that some worlds could have no sun or moon while others could have several of either. He also proposed that a world could be destroyed by collision with another world. As for the Milky Way, he believed that it was made up of countless stars, so distant that they were hardly visible, but shining together they formed this bright band in the sky.

Unfortunately, the theories of Democritus became less popular with time; of his numerous works only fragments remain, quoted by other authors. It would take 25 centuries or so for science to prove him right.

Image credits:

Milky Way




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