Picturing the Poles
Beyond the asteroid belt lies Jupiter. Jupiter is the largest planet in the solar system— 11 times the diameter of Earth. Since 2016, a NASA spacecraft named Juno has been orbiting Jupiter.
Jupiter spins faster than any other planet in the solar system—once every 9 hours and 55 minutes, compared to once a day on Earth. This rapid spin creates belts of gas that run from west to east across the planet. Juno took pictures of Jupiter’s north and south poles for the first time. These are very different from the rest of the planet. There are no gas belts there. Instead, the planet’s poles have vast, swirling storms.
This artist’s rendering shows how Juno looks as it orbits Jupiter.
Farther and Further
There’s plenty of space to explore beyond Jupiter. In 2006, NASA launched a spacecraft named New Horizons. The spacecraft used Jupiter’s gravity to slingshot itself toward Pluto. Pluto is the ninth largest object that goes around the sun.
Nine years after its launch, New Horizons flew past Pluto, showing us pictures of mountains three miles high. These mountains aren’t made of rock. They’re made of water-ice. Pluto is so cold that this substance is as hard as rock and can form tall mountains. This was an important discovery. Scientists want to know more about how these mountains formed.
New Horizons is still going. It flew past the farthest object ever visited: Arrokoth. Much smaller than Pluto, Arrokoth is made of two objects stuck together. It looks like a snowman in space! From tip to tip, it is about 35 kilometers (22 miles) long.
Scientists think its two parts were once separate. They went around each other, the way the moon goes around Earth. Then, little by little, they got closer and closer to each other and eventually joined together.
This artist’s drawing, based on images taken by the spacecraft New Horizons, shows the most distant object ever visited by human spacecraft.
Voyager now explores interstellar space, as shown in this artist’s drawing.
Arrokoth is far, far away. Believe it or not, some spacecraft have traveled even farther. For example, Voyager 1 and Voyager 2, which NASA launched in 1977. Voyager 1’s mission was to fly by Jupiter and Saturn. Voyager 2 flew by Jupiter, Saturn, Uranus, and Neptune.
Both spacecraft kept going and are now really far away but are still sending data back to Earth. Voyager 1 is nearly 22 billion kilometers (14 billion miles) from the sun. That’s nearly 150 times farther than Earth is to the sun. Voyager 2 isn’t far behind.
Both spacecraft are now exploring interstellar space. That’s the region between stars. This is the first time a spacecraft has gone into it to see what it’s like.
Why do we explore the solar system? Because we are a part of it. We want to know more about the place where we live. Each mission teaches us more and shows us fascinating new places in space.