2. The Milky Way, with approximately 200 billion stars, is just one of about 100 billion galaxies in the Universe.

5. NASA History Highlights

8. Rotation day turns into night

11. Winter, Spring, Summer, Fall

13. Endeavour's crosstown journey

18. Comparing Stars

21. You Are My Sunshine In the grand scheme of things, the Sun is no big deal. It’s just another medium-size star in a remote corner of the Milky Way Galaxy. There are billions of others in the Universe just like it. But to us here on Earth, the Sun is hugely important. Without it, our world would be a frozen rock wandering in space. Among other things, the Sun gives us food, energy, seasons, weather, calendars, flowers, light, and some really wicked sunburns! 1. The Sun provides Earth with a tremendous amount of energy. Why is this energy so important to life on Earth? 2. Why does the Sun appear to rise and set each day? 3. If the Sun is just an average, medium-size star, then why does it look bigger than all the other stars in the sky?