Today is National Milky Way Day. Here are 10 facts about our galaxy:
The Milky Way seems like a funny name for a galaxy. It got its name back in ancient times, before Telescopes were invented. Without a telescope, all the stars blur together into a white streak across the sky which the Romans called the via lactea, or "road made of Milk".
Greek mythology went a step further and came up with a theory as to its origins. They stuck with the milk theme – mother’s milk, to be exact. The story goes that in an attempt to make his son by a human woman, Hercales, immortal, his father placed him on Hera’s breast while she was asleep in the hope that drinking her milk would grant him eternal life. Hera woke up to find she was nursing a strange baby and pushed it away. The milk she spilled in the process became the Milky Way.
Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610.
Caer Gwydion ("The fortress of Gwydion") is the traditional Welsh name for the Milky Way.
The Milky Way is approximately 14 billion years old.
It’s approximately 100,000 light-years in diameter. The bulge in the middle is about 10,000 light-years thick and the spiral arms are about 1,000 light-years thick.
Everything in it rotates around the centre, including our Solar System. It takes 250 million years for our Sun to make one revolution around the Milky Way.
About 10-15% of the Milky Way’s visible matter is made of dust and gas, with the rest being stars. It is estimated to contain 100–400 billion of them.
The Milky Way has a supermassive Black Hole in the middle called Sagittarius A*. This black hole has an estimated diameter of 14 million miles.
Our solar system is 26,000 light-years from the centre of the Galaxy.
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