Notes

I’m going to teach you about the Milky Way galaxy including fun facts, pictures, and other stuff like that. So let’s start. the first thing I am going to teach you is about it’s discovery. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Did you know that the Milky Way wasn’t always the Milky Way? It was actually made from other galaxies! It became its current size and shape by eating up other galaxies, and is still doing so today. Next I am going to tell you about its unique shape. The Milky Way is a huge collection of stars, dust and gas. It's called a spiral galaxy because if you could view it from the top or bottom, it would look like a spinning pinwheel. Even if you could travel at the speed of light (300,000 kilometers, or 186,000 miles, per second), it would take you about 25,000 years to reach the middle of the Milky Way. the Milky Way has a supermassive black hole at its center called Sagittarius A*. This black hole has an estimated diameter of 14 million miles, which does not include the disk of mass being drawn into it. Also, the Milky Way is about 100,000 light years across. If you could travel at the speed of light, an impossibility due to Special Relativity, it would still take over 26,000 years to arrive! A Greek mythology said that the Milky band of light was coming from Hera feeding Hercules. Another cool fact about the Milky Way is that The Chinese call the Milky Way the Silver River. Chinese mythology said that it was put there by the gods to deter a herdsman who was in love with a weaver woman who used to weave clothes for them. Another cool fact is that If the solar system were the size of U.S. quarter, earth would be about the size of the United States and the sun would be a very tiny speck of dust. Since the dinosaurs became extinct, about 65 million years ago, the sun has traveled just about a third the way around the center of the Milky Way. Also, While the Milky Way contains up to about 400 billion stars, you can only see 0.0000025% of all the stars when you look up the sky at night. That’s a lot of stars! At the center of the Milky Way is one of the strangest and deadliest things in the universe: a black hole. Black holes are born when a giant star runs out of energy. The star implodes, causing an explosion called a supernova. The star’s heart collapses under its own weight. It’s squashed into a tiny dot you can’t see.







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