On a winter night a few years ago, as I was walking across the coastline to get home after work, I noticed that one of the stars, shining southeast and right above the sea, was lower in the sky and brighter than the others. It sparkled and seemed to be constantly changing colors. From that night onward, I would always look for it and greet it. “Hello Sirius!”
It is Sirius, the “dog star”. It is the brightest star in the earth’s sky, and it's sparkly and colorful. Even its name means "sparkling" or "scorching". But stars are tricky and things are not always what they seem! Here are a few facts you might not have known about Sirius:
[1] It is actually made of two stars, not one
Sirius is a binary star system, which means that what our eyes perceive as one star is actually two stars orbiting each other. We mainly see and refer to Sirius A, which is a bright, main sequence star. But Sirius A has a companion, Sirius B, a faint white dwarf. Sirius B can only be viewed through a telescope.
[2] It is actually not that bright
Sirius A is twice as big as our sun but 25 times more luminous! Even so, it's not among the brightest stars we know. Sirius is one of our closest neighbor stars, and its proximity to earth makes it appear as the brightest star in our sky (apart from some planets of our solar system, which appear in the sky like bright stars).
[3] It’s not really changing colors
Sirius seems to be changing colors all the time, but this is a visual trick of its light diffusing in the atmosphere. When a star appears low in the sky, its light has to go through a dense layer of atmosphere to get to our eyes, which splits its light. And since Sirius is so bright, the effect is much more noticeable.
Its "real" color is white to white-blue, but due to the above, Sirius is often known as the rainbow star. Amanda Cross in the UK caught the below images of Sirius on December 11, 2017:
So yeah, our dog star is a little cheater!
Sirius is the dominant star in the constellation of the greater dog, “Canis Major”. In the Northern hemisphere, Sirius rises in the southeast and sets in the southwest, while in the Southern hemisphere, it arks high overhead.
Sirius rises in mid-evening in December, and sets in mid-evening in April. In the northern hemisphere, Sirius hides behind the sun during the summer and re-appears in the east before sunrise in late summer. This is called the “heliacal rising” of the star, and its very precise in relation to other stars. This subsequently helped ancient Egyptians to base their calendars on it. For peoples in the Southern hemisphere, the star marks the winter and for the Polynesians, it used to be an important reference for navigation in the Pacific ocean.
Stories about Sirius
The star was treated as sacred in many cultures and religions and was accompanied with festivals and celebrations. Most ancient cultures around the world associated the star with either a dog or a wolf concept. “Dog of the sun”, “wolf star”, “dog face”, “moon dog” were some of the names that ancient peoples named the star.
Early stargazers of the northern hemisphere might have imagined that Sirius, so close to the sun, helped it to cause the summer heat. These days were therefore called the “dog days”. The ancient Greeks and Romans believed that these days could impact the behavior of dogs! This was mainly due to the fact that dogs panted more during the summer, and rabies outbreaks were more common. It also believed that the star could alter the behavior of humans, causing them to become “starstruck”. Plants wilted, men weakened, and women became more aroused as a consequence of Sirius rising!
Egyptians noticed that Sirius rose each year just before the Nile flooding. Floods brought both destruction and new fertile soil. Therefore the star became associated with Osiris, the god of life, death, fertility and rebirth of plant life, and Sopdet, an agricultural deity. Sirius was also associated with Anubis, the dog-headed god of death, as well as most other important deities.
In iranian mythology, Sirius was considered as the divinity of rain and fertility, with the local name Tishtrya. It was the opponent of Apaosha, the demon of drought. Some ancient Hindu writings also refer to Sirius as Sukra the “rain god” or “rain star”.
In China, as well as Japan, the star was known as the star of the “celestial wolf”. It was said to symbolize invasion and plunder. In the links below you can find myths and cultural events that honored Sirius as an important divine entity.
References:
http://earthsky.org/brightest-stars/sirius-the-brightest-star
https://en.wikipedia.org/wiki/Sirius
https://www.space.com/21702-sirius-brightest-star.html
http://www.ancient-origins.net/history-ancient-traditions/what-so-special-about-sirius-dog-star-009232
http://www.ianridpath.com/startales/canismajor.htm
https://vigilantcitizen.com/hidden-knowledge/connection-between-sirius-and-human-history/
