Page 8 - The Universe and You
P. 8
Earth looks like a brilliant blue ball (with a few white The sizzling surface of the sun reaches 9,941 degrees
clouds overhead) because nearly three-fourths of its Fahrenheit (5,505 degrees Celsius!). The sun is so
surface is covered with water. Credit: NASA massive that more than one million Earths could fit
inside it. Credit: NASA/GSFC/Solar Dynamics Observatory
Exploring the Universe
Earth is always on the move! It spins around an imaginary line through its center called an axis,
and makes one complete rotation in 24 hours. That’s why a day lasts 24 hours.
Earth orbits, or circles, the sun, along with seven other planets—Mercury, Venus, Mars, Jupiter,
Saturn, Uranus, and Neptune. They are part of our solar system (which also contains dwarf
planets, moons, and other small celestial bodies). The sun’s large mass creates a powerful
force called gravity, which holds the solar system together.
