- Our Sun has lots of company: it is one of more than 200 billion stars in the Milky Way Galaxy alone. Every individual star that you can see with the naked eye is in the Milky Way.
- But there are many more stars than that. There are perhaps 40,000,000,000,000,000,000,000 stars or more!
- Stars are factories for new elements. As they live and die, they convert their hydrogen gas into all the rest of the elements on the periodic table. These elements make up Earth and you.
- A star's mass—how much matter it contains—determines its temperature, luminosity, color, and how it will live and die.
- Our Sun is more massive than the average star. Nearly 90% of stars are less massive, making them cooler and dimmer.
- The hottest and most massive stars are bright and blue, while the coolest and least massive stars are dim and red. Yellow stars like our Sun are in-between.
- About 99% of stars, including our Sun, will end their lives as white dwarfs. Only about 1% of stars are massive enough to explode as a supernova.