Why are Geminis called the twins in the night sky?

In winter, although there is no obvious Milky Way landscape in summer, there are no Scorpios with their teeth and claws, and men and horses with bows and arrows shooting at the stars, but the star-studded Orions, the shining Sirius and the joyful and galloping Taurus also make winter The starry sky at night is very lively. There is a pair of good brothers who patrol the night sky hand in hand in the cold winter. They are the twins in the night sky - "Gemini".

Gemini is easier to find in the night sky. The simplest and most intuitive way is to first find the symbol of the winter constellation - Orion, and then combine Rigel (the upper left corner of the three-star belt) and Betelgeuse (The lower right corner of the Samsung Belt) By connecting and extending the distance by about twice, you can find a pair of bright stars that are not too far apart. They are only about 4.5° apart and are the alpha stars (Pollux) and beta stars (Pollux) in the constellation Gemini.

In ancient Western mythology, Gemini’s elder brother Castor is the son of the king of Sparta, and his younger brother Pollux is the son of Zeus, so he is immortal. The two grew up together and have a very good relationship. After his brother Castor died, only the immortal Pollux remained. So Pollux asked Zeus, hoping to go to hell with Castor. Zeus then agreed that the two brothers would take turns living in heaven and the underworld. In memory of the twin brothers, ancient Rome also built temples for the twin brothers - the Temple of Castor and Pollux.

Gemini is one of the zodiac constellations, with an area of ??513.76 square degrees, accounting for 1.245% of the entire sky. It ranks 30th among the 88 constellations in the sky. There are 47 stars brighter than magnitude 5.5 in the Gemini sky area. The brightest star is Pollux, with an apparent magnitude of 1.14. The center of the constellation Gemini passes through the midheaven on the night of January 5 every year, which is just above the observer's head.

Although the Gemini β star (Pollux) is named a "β" star, it looks brighter than the "α" star (Pollux) from the earth. It is 33.7 light-years away from the earth and has a luminosity 32 times that of the sun. It is one of the nearest red giant stars and one of the brightest stars in the universe. When observed with binoculars, the orange color of Castor is in sharp contrast with the blue color of Castor, which is very beautiful. This magnificent scene can be clearly seen in most areas of our country.

Although Castor and Castor are described as the "Twins" of the constellation, their characteristics are quite different. The former is a bluish-white main sequence star, while the latter has entered the red giant stage. Moreover, Castor and Castor are still moving in two opposite directions.

Speaking of Gemini, we have to mention another famous celestial phenomenon related to it - the Geminid meteor shower. As one of the three most stable meteor showers in the northern hemisphere (the other two are the Quadrantid meteor shower on January 4 and the Perseid meteor shower around August 13), it comes to the earth on the night around December 13 every year , and make those days a carnival night for astrophotography enthusiasts. The Geminid meteor shower is a large-scale explosion of meteors in a relatively short period of time with the sky near the Gemini constellation as the radiant point. At its peak, the zenith flow can reach about 120 meteors per hour.

The parent body of the Geminid meteor shower is the asteroid 3200 Phaethon, which makes it one of the few meteor showers whose parent body is not a comet. Most of the meteors in its group are bright and medium-speed meteors. In addition to white meteors, there are also There are many colors such as red, yellow, blue, green and so on. In December last year, under the organization of domestic enthusiasts, the author went to Tongliao, Inner Mongolia in four teams to observe and photograph the meteor shower. In the cold weather and freezing ground, I felt and recorded the magnificent beauty of falling stars like rain.