Draco — the forgotten constellation


By Tom Burns - Stargazing



How the mighty have fallen. A scant 5,000 years ago, the constellation Draco, the Dragon, was in its prime. The dragon appears in the myths and legends of every major ancient civilization. Your average Babylonian worshipped it as a god. These days, few of us would recognize it if it fell out of the sky and hit us on the craniums.

It’s hard to understand why. Draco is huge, the eighth largest constellation in the heavens. It is prominently placed near the most familiar star in the sky, Polaris, the North Star. All you have to do is look north. Draco’s serpentine tail slithers awkwardly around the more familiar Little Dipper.

Draco was an important constellation to the ancients in large part because of a single star, which was fervently worshipped by the ancient Egyptians.

However, the star and its parent constellation aren’t particularly bright, and these days, it isn’t even particularly well placed in the sky. Why was it so important? And why isn’t it important now?

The answer lies in a couple of constellation stories and a bit of celestial navigation.

For starters, Draco goes way back to the very beginning of human civilization 6,000 years ago. In most cultures, it was associated with darkness and evil. The ancient Babylonians recognized it as a great dragon called Tiamat, the symbol of the chaos and disorder that seemed to surround them. Tiamat opposed the gods, controverting their attempts to impose order on the natural world.

He was finally defeated by the sun god Izhdubar, the bringer of light who imposed law and order on the world. Izhdubar is represented by the nearby constellation we call Hercules. In a stupendous battle, Izhdubar drove a great wind into the monster’s open jaws, and thus split him in two.

Three millennia later, the ancient Greeks were so fascinated by the constellation that they associated it with two very important characters in their mythological canon.

According to the Greeks, the traditional gods did not always rule the universe. A motley crew of god-like creatures called the Titans preceded them. Sadly, most of the gods were children and grandchildren of the Titans, but the Titans treated them badly. For example, Saturn, the king of the Titans, swallowed his children whole to prevent them from usurping him. Zeus (Jupiter to the Romans) escaped that cruel fate, and later led the rebellion against their titanic torturers.

At one point in the battle, Zeus’s daughter, Athena, stood before the great, fire-breathing serpent we now call Draco. To avoid getting flambéed, Athena grabbed Draco by the tail and flipped him up to the sky. Because he undulated uncontrollably upward to the heavens, Draco stuck there in the awkward position that we see him in to this very day.

The ancient Greeks also associated Draco with the giant dragon Ladon, one of the extremely nasty household pets of Hera, queen of the gods. Ladon’s job was to guard the golden apples that grew on a tree planted in Hera’s garden on the slopes of Mount Atlas. Three beautiful sisters, called the Hesperides, were originally assigned the job of guarding the apples, but they couldn’t resist picking them.

So Hera added Draco, who coiled himself around the tree. And a worthy guard he was. He had 100 heads, each of which was deadly.

Along came Hercules (yes, him again), the greatest of the Greek heroes, who was assigned the job of stealing the apples as one of his twelve labors.

He slew the dragon with arrows he had dipped in the poisonous blood of another of Hera’s pets, the Lernean Hydra. He then made off with the apples.

The next day, a group of famous Greek adventurers called the Argonauts came upon the scene.

The sight they saw was worthy of any of the sleazy horror movies so popular these days. The Hesperides wailed over the corpse of the dragon.

Draco was even nastier in death than he was in life. Dead flies covered the dragon’s body. The Hesperides soon died an agonizing death themselves from trying to drink the dragon’s now-poisoned blood.

Hera loved her pet anyway. To honor his memory, she put him among the stars, where he is to this day.

Not all cultures saw the constellation as an evil beast. To the ancient Chinese, it was an ultimately important locale — the dwelling place of the ruler of the sky. It was called Tsi Kung, the “Palace of the Heavenly Emperor.” At the curve of the dragon’s tail was Tien Choo, or Heaven’s Kitchen. The stars of the tail behind it were various governmental ministers and palace servants, including stewards and even the palace governess.

And now we can finally return to our original questions.

Why have we lost track of Draco when the almost equally faint Little Dipper it wraps around is so familiar to us?

Most people know the Dipper because it contains a single star called Polaris. Polaris is now the pole star, the star that happens to be almost straight north.

As a result, it seems to stand still while the other stars circle slowly around it.

Because the earth wobbles a little on its axis as it rotates, the pole star changes over the millennia. Five thousand years ago, the faint star Thuban in Draco’s tail, and not Polaris, was almost directly north.

To the Egyptians, Thuban was the place where their dead Pharaoh entered the heavenly realm and joined his compatriot gods. To others, Thuban was the nail that held up the heavens, the single unchanging point in an ever-changing cosmos.

Draco was thus the most important constellation in the sky, and that fact is reflected in the old stories. But Earth wobbles slowly on its axis, and as a result, Thuban and Draco have sadly faded from our memory.

But not to worry. As the Earth continues to wobble, Thuban will again return to its former glory as the Pole Star in the year 21,000 CE or thereabouts.

Let’s hope that humans beat the odds against our survival for so long a time. Perhaps then, they will restore Thuban to its old glory. It is extremely unlikely that they will remember the old stories. Perhaps they will make up a few of their own.

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By Tom Burns

Stargazing

Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.