A tender gaze between mother and child
In the night sky of the Northern Hemisphere, Ursa Major and Ursa Minor have long been used for navigation, revolving steadily around the North Star.
According to myth, the beautiful Callisto served as a devoted attendant to Artemis, the goddess of the moon, and was a skilled hunter deeply trusted by the goddess. One day, she bore a son named Arcas as a result of Zeus’s pursuit. Consumed by jealousy, Hera punished Callisto, stripping her of her beauty and voice, and transforming her into a giant bear. Once admired as a hunter, Callisto became a creature hunted by others. She wandered the forests, evading beasts and humans alike, her thoughts always with her son Arcas.
Time passed, and Arcas grew into a brave hunter. One day, he encountered a bear approaching him through the forest. This bear was, of course, his mother Callisto. Overcome with joy at seeing her son after so many years, she forgot her ursine form and rushed toward him. To Arcas, however, this was a massive beast preparing to attack.
As Arcas raised his bow to strike, Zeus intervened to prevent the tragedy. He transformed Arcas into a young bear and lifted both mother and son into the sky by their tails, placing them forever as Ursa Major and Ursa Minor. Interestingly, because Zeus had held them by their tails when casting them into the sky, the tails of both bears appear longer in the constellation than they would in reality.
Observation Guide
Ursa Major is one of the most recognizable constellations in the Northern Hemisphere, with its seven bright stars forming the famous Big Dipper. The stars from the bowl to the handle are known as Dubhe, Merak, Phecda, Megrez, Alioth, Mizar, and Alkaid. Extending a line five times the distance from Merak through Dubhe points directly to Polaris, the end of Ursa Minor’s tail.
Ursa Minor has a similar dipper-shaped arrangement, appearing like a smaller version of the Big Dipper, which may explain why the two constellations were historically associated with each other.
It should be noted that constellations are human-made patterns. While gazing at the night sky, stars appear to lie on a single plane, allowing people to connect nearby stars into imagined shapes. People can envision a massive sphere surrounding Earth, with stars seemingly attached to its surface. This imaginary sphere is called the celestial sphere. Based on this view, humans grouped neighboring stars together to form constellations. In reality, stars are independent of one another, each moving through space, which is a phenomenon astronomers call proper motion. Due to the vast distances involved, these movements are almost imperceptible within a human lifetime.
However, over tens of thousands, hundreds of thousands, or even millions of years, the familiar shapes of constellations will no longer exist. For example, astronomers have calculated the changing shape of the Big Dipper from 100,000 BCE to 100,000 CE. In the distant future, the constellations known today may be entirely reimagined, and new patterns may be drawn across the night sky, inspiring fresh stories and new ways of seeing the stars.
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Easter Egg
He looked up at the Big Dipper and suddenly realized
what proper motion meant,
which he had just learned today.
