The constellation Ursa Minor

The constellation Ursa Minor

Ursa Minor (little bear) is a constellation of the northern hemisphere. It is circumpolar around the North Pole. This means that its stars are so close to the celestial pole that they never set as seen from Berlin. The constellation is therefore above the horizon all year round there. Ursa Minor looks similar to the Big Dipper in the constellation Ursa Major (great bear). For this reason, this constellation is also often called the Little Dipper. However, while the handle of the Big Dipper curves downwards, the handle of the Little Dipper curves upwards.

At the end of the handle, that is, at the tail of the little bear, lies α Ursae Minoris, better known as Polaris or the Pole Star. Polaris has a very special role. Because it lies almost exactly above the geographic North Pole, it is the only star in the northern hemisphere that always stays in the same place in the sky. It lies almost exactly above the Earth's axis, around which the Earth turns once every 24 hours. Polaris is the only star, apart from its southern counterpart in the constellation Octans, that does not take part in this rotation. The Phoenicians were already navigating by the Little Dipper, because it circles the pole more tightly than the Plough and therefore points more precisely to the north.

However, because of the wobble of the Earth's axis, Polaris will not keep this special feature forever. In a little over a thousand years, the star Errai in the constellation Cepheus will be closer to the celestial pole than today's pole star; it will come closest to the pole around the year 4000. And in about 8,000 years, people will see the pole star in the star Deneb in the constellation Cygnus.

Mythology

Callisto was a nymph in the company of the goddess Artemis, the goddess of hunting. According to a Greek legend, Zeus one day turned himself into Artemis in order to get close to Callisto. Callisto suspected nothing until Zeus showed his true face and forced her to give in to him. Callisto became pregnant and, because she had broken her vow of chastity to Artemis, she was banished from the goddess's company. When she gave birth to her son Arcas, Hera, the betrayed wife of Zeus, could no longer hold back her jealousy. She threw Callisto to the ground and turned her into a she-bear. For fifteen years, Callisto roamed the forest in the form of a she-bear, until one day she met her son Arcas. But Arcas, who had no idea who she was, tried to kill the she-bear. Before anything worse could happen, Zeus stepped in and sent a whirlwind that carried mother and son up into the sky. There he immortalised Callisto in the constellation Ursa Major (Great Bear). Some retellings see her son Arcas in Ursa Minor (Little Bear), but the ancient star myths see him in Boötes.