Cassiopeia英文介绍英语课上要演讲的,

Cassiopeia英文介绍英语课上要演讲的,
Cassiopeia英文介绍
英语课上要演讲的,

Cassiopeia英文介绍英语课上要演讲的,
There are a handful of constellations that beginning stargazers of all ages can learn to locate right away.These constellations are easy to spot because they contain a distinctive asterism--a recognizable star grouping.One of these constellations is Cassiopeia the Queen,with its defining asterism,the “Lazy W,” visible even in the city.
In legend,the beautiful but beleaguered Cassiopeia (pronounced kass ee oh PEE yuh) was the queen of ancient Ethiopia.She was the wife of King Cepheus (pronounced SEE fee yuss) and the mother of Andromeda.The queen’s vanity was her undoing.She rashly boasted that she was more beautiful than the sea nymphs.The miffed ocean-dwelling goddesses,fifty in number,appealed to their protector,the sea god Poseidon.He retaliated by sending the sea monster Cetus to ravage Ethiopia’s coast.Consulting an oracle for guidance,King Cepheus learned that he had to sacrifice daughter Andromeda to the monster in order to appease the angry god.That is how Andromeda came to be chained to a rock by the sea,waiting for her nick-of-time deliverance by the hero Perseus.
The Lazy W’s bold,connect-the-dots pattern makes it easy for us to see why Cassiopeia is one of the oldest constellations,known to numerous ancient cultures and mentioned in Greek literature of the 5th century BCE.Known to the early Arabs as “The Lady in the Chair,” she is usually depicted sitting on a throne.But the gods had the last laugh.They placed the self-absorbed royal in the sky such that she spends half of her time upside down,a most undignified position for a queen.
The astronomical explanation for Cassiopeia’s topsy-turvy existence has to do with it being a circumpolar constellation.In the Northern Hemisphere,a circumpolar constellation is a constellation that circles the North Celestial Pole,the imaginary fixed point in the sky that the Earth's axis would intersect,were it extended northward.This imaginary point just happens to be extremely close to the star Polaris,which is why we call Polaris the North Star.
In latitudes above 35 degrees north,circumpolar constellations never set; they are always above the horizon as they endlessly circle the North Star counterclockwise,making one revolution per day.But although we commonly say they are "circling," constellations like Cassiopeia are not really moving around the Pole.Their apparent motion--or the way they appear to move in our sky--is actually caused by our rotation,as planet Earth reliably spins 24/7 on its axis.