By Tom Burns
The summer sky is crowned by the most beautiful – and mysterious – sight the universe has to offer — the glorious river of light called the Milky Way.
In June, it rises in the east in the early evening. By late summer, it stretches across the vault of heaven like the backbone of God.
You’ll need dark, rural skies to see it in all its complexity. The growth of city lighting has seen to that. Our ancient forebears had one thing going for them that all our technological advances have come to erase. Their skies were unmarked by the stain of light pollution. They saw the Milky Way in all its mind-altering glory.
However, of its causes they had not a clue, and the mystery of its origin lasted thousands of years. Over the next few columns, I’ll trace the history of our slowly rising knowledge of its true nature. I hope you will come along for the ride.
The story starts with the myths and legends that people told long ago. Many natural mysteries were explained away by the capricious nature of our gods or by what the cultures depended upon for their survival or success. The Milky Way is no exception.
Practically every culture of Earth tells such stories. The ancient Egyptian culture saw the Milky Way as the work of the god Isis, who had spread an abundance of life-giving wheat across the sky. Across the world, the Incas, who were lovers of the beauty and wealth that gold produces, saw as a steam of gold dust. The Inuit people of the Arctic believed they saw a snowy band. The inhabitants of Australia saw in it the ash of the campfires they had set against the cold and dark of the night.
Often, ancient people depicted rivers and the creatures that lived in them. The Arabs who lived in the parched deserts saw an unattainable river of water. Polynesians called the Milky Way a cloud-eating shark. Fishers in the Orient saw a school of fish frightened away by a fishhook, which they fancied to be the thin, crescent moon. Native American of the Great Lakes region saw a muddy creek stirred up by a giant mud turtle crawling across the sky.
Most often, ancient cultures saw it as a road or path, quite literally a “way.” To the early Hindus of India, it was the path of their god Aryaman upward to his heavenly throne. To those who lived on the banks of the Yellow River in China, it was a yellow road, their life-sustaining river extended into the heavens. The Celtic denizens of Wales saw it as the path that their trickster and warrior hero Gwydion left as he pursued his fleeing wife. In Norse mythology, the Milky Way is the road to Valhalla, the final home of brave warriors who died in battle. The Iroquois described it as the path to eternal life after death, the “Road of Souls.” To travelers seeking the center of civilization of its time, it was the “Road to Rome.”
Ovid, perhaps the greatest of all Roman poets, describes it as the shining road to Olympus and from there to the palace of Zeus, the king of all the gods: “By this way the gods fare to the halls and royal dwelling of the mighty Thunderer.”
The ancient Greeks saw the Milky Way as a tragic tale of betrayal and vengeance. As told by the poet Eratosthenes, it reflects their almost-human failings raised to superhuman proportions.
Zeus, or Jupiter to the Romans, was the king of all the gods, and he was used to getting his own way. He betrayed his wife Hera with a kind of offhanded but merciless zeal.
Hera was pretty much forced to put up with his philandering. Zeus was far more powerful than she, so she couldn’t express her anger directly.
At long last, she had a mortal baby to torture. Alcides, as he was called at birth, was the illegitimate offspring of Zeus, king of the gods, and Alcmene, a mortal woman. His half mortal half immortal parentage caused no end of trouble for the babe throughout his exceedingly difficult life.
For starters, Hera sent two large serpents to kill the baby in its crib. But the babe was exceedingly strong. He reached out with his chubby, little hands and squeezed the life out of the serpents.
Zeus knew that the baby was in mortal danger. Heracles, as he came to be called, must drink the mother’s milk of a goddess to achieve the immortality of a god. Hera, as you might imagine, was unwilling to provide such a service to Zeus’s lust child. Zeus thus sent his messenger Hermes to lay Alcides beside her as she slept. The infant did what came naturally by suckling the milk of immortality. Did I mention that the babe was exceedingly strong? Hera awoke in pain and pushed the babe away. Her milk streamed across the sky as a glowing band of light we call the Milky Way to this very day.
None of the Milky-Way tales sound particularly “scientific” by our standards. However, in another Greek myth we find the hint of a more satisfactory explanation that would eventually arrive far down the path of centuries. More on that next week.
Tom Burns is the director of Perkins Observatory. He can be reached at firstname.lastname@example.org.