In ancient times, people didn’t even know the planet Neptune existed. Astronomers, scientists who study space, didn’t discover the big blue planet until the 1840s.
Neptune is usually the eighth planet from the Sun. So far as astronomers know, only the planet Pluto is farther from the Sun. However, Pluto’s orbit sometimes brings it closer to the Sun than Neptune is, making Neptune the planet farthest from the Sun. This happens every 248 years.
Astronauts on a space shuttle mission can see planet Earth below. They see different parts of Earth as the shuttle goes around the planet. The shuttle is in orbit above Earth. An orbit is a curved path going around something in space.
WHAT KINDS OF THINGS ORBIT IN SPACE?
The Moon orbits Earth. Space shuttles and artificial satellites also orbit Earth.
Spacecraft sent to explore distant planets sometimes go into orbit. A spacecraft orbits a planet and takes pictures and measurements.
You hear a rumble and a roar. A blast of fire shoots out of a big rocket. The rocket heads up into the air. Maybe the rocket is carrying a satellite into orbit around Earth. Maybe the rocket is carrying a space probe to another planet!
Only a big rocket can make it into outer space. No other machine is as powerful as a rocket.
WHAT DO ROCKETS LOOK LIKE?
A rocket looks like a long tube. Most rockets have fins on the back end to help them fly straight.
Our Sun would look like a small dot of light if you were standing on the surface of Pluto. But Pluto is so far away that no spacecraft has ever visited it. Pluto is the ninth planet in our solar system. Astronomers know less about Pluto than about any other planet.
Pluto is currently the farthest planet from the Sun. It goes around the Sun in an oval-shaped path called an orbit. It takes almost 248 Earth years for Pluto to go around the Sun once. Sometimes Pluto’s orbit brings Pluto closer to the Sun than the eighth planet, Neptune. During that time, Pluto is the second farthest planet from the Sun. Neptune is farther.
How does a television signal get to the other side of the world in seconds? What tells ships exactly where they are in the middle of the ocean? How do we get warning that storms are coming? Satellites do all these things and more.
WHAT ARE SATELLITES?
Satellites are objects in outer space that fly around planets in circular paths called orbits. Artificial satellites are made by people. Thousands of satellites are zooming around our planet right now.