Excerpt
Introduction
Pluto is one of the most interesting places in the solar system, and for a long time, it was one of the most mysterious. It was the last planet to be discovered in our solar system—except, as you might already know, it isn’t called a planet anymore. Pluto is now a dwarf planet, and that change sparked a lot of debate. People argued about it. Scientists had meetings about it. Even today, some people still refuse to accept that Pluto isn’t a planet. But what makes Pluto different from the planets? And how did we go from knowing almost nothing about it to having close-up pictures of its surface?
Pluto is way out in a part of the solar system called the Kuiper Belt. That’s a huge area full of icy objects, some of which are even bigger than Pluto. Because it’s so far away, for a long time, Pluto was just a tiny dot in space. Even with the best telescopes on Earth, scientists could barely see any details. No one knew what its surface looked like, what it was made of, or if it had any moons. They just knew it was out there, orbiting the Sun in a way that was different from all the planets. Then, in 2015, something amazing happened—NASA’s New Horizons spacecraft flew past Pluto, and for the first time ever, people got to see it up close. That was when we learned just how unique and surprising Pluto really is.
The surface of Pluto turned out to be covered in ice, but not just one kind. Some of it is made of frozen nitrogen, some is frozen water, and some is frozen methane. It even has mountains that are probably made of ice as hard as rock. And right in the middle of Pluto’s surface, there’s something incredible—a huge, smooth, heart-shaped glacier. That’s right, Pluto has a heart! Scientists named it Tombaugh Regio, after Clyde Tombaugh, the man who discovered Pluto in 1930. It’s one of the strangest and most unexpected features ever found in the solar system.
But Pluto isn’t just a lonely ball of ice. It has five moons, and one of them, Charon, is almost half the size of Pluto itself. In fact, Pluto and Charon are so close in size that they don’t orbit the way most planets and moons do. Instead, they move around a shared center of gravity, almost like a pair of dancers spinning around each other. This is different from how Earth and the Moon move together. If you could stand on Pluto and look up at Charon, you’d see a giant moon that never changes position in the sky. It would just stay in one spot while Pluto rotated underneath it.
Because Pluto is so far from the Sun, it takes a very long time to complete just one trip around it. A year on Pluto is about 248 Earth years long. That means that since the time Pluto was discovered, it still hasn’t even finished one full orbit! Seasons on Pluto last for decades, and when it’s winter, the atmosphere actually freezes and falls to the ground like snow. When the planet moves closer to the Sun, some of that frozen gas turns back into an atmosphere, but it’s nothing like the one we have on Earth. The air around Pluto is incredibly thin, and it’s mostly made of nitrogen, just like the ice on its surface.
People have always been curious about Pluto, but because of its small size and its unusual orbit, it didn’t quite fit in with the other planets. It was much smaller than Mercury, even smaller than some of the moons of Jupiter and Saturn. It also had an orbit that was more tilted and stretched out than the round, steady paths of the planets. That’s why, in 2006, scientists decided that Pluto wasn’t a planet after all. They made a new category called “dwarf planets” for objects like Pluto—things that are round and orbit the Sun but don’t meet all the rules for being a planet. Some people were upset about this change, and even today, there are scientists who argue that Pluto should still be called a planet.
Pluto may be small, but it has taught scientists a lot about the solar system. The discovery of Pluto led to the discovery of the Kuiper Belt, which turned out to be full of other icy worlds. It also helped scientists understand that the solar system is even more complicated and interesting than they once thought. And because of New Horizons, people now know more about Pluto than ever before. It’s no longer just a tiny dot in space—it’s a world full of surprises, with glaciers, mountains, and an atmosphere that comes and goes.
Pluto is one of the most interesting places in the solar system, and for a long time, it was one of the most mysterious. It was the last planet to be discovered in our solar system—except, as you might already know, it isn’t called a planet anymore. Pluto is now a dwarf planet, and that change sparked a lot of debate. People argued about it. Scientists had meetings about it. Even today, some people still refuse to accept that Pluto isn’t a planet. But what makes Pluto different from the planets? And how did we go from knowing almost nothing about it to having close-up pictures of its surface?
Pluto is way out in a part of the solar system called the Kuiper Belt. That’s a huge area full of icy objects, some of which are even bigger than Pluto. Because it’s so far away, for a long time, Pluto was just a tiny dot in space. Even with the best telescopes on Earth, scientists could barely see any details. No one knew what its surface looked like, what it was made of, or if it had any moons. They just knew it was out there, orbiting the Sun in a way that was different from all the planets. Then, in 2015, something amazing happened—NASA’s New Horizons spacecraft flew past Pluto, and for the first time ever, people got to see it up close. That was when we learned just how unique and surprising Pluto really is.
The surface of Pluto turned out to be covered in ice, but not just one kind. Some of it is made of frozen nitrogen, some is frozen water, and some is frozen methane. It even has mountains that are probably made of ice as hard as rock. And right in the middle of Pluto’s surface, there’s something incredible—a huge, smooth, heart-shaped glacier. That’s right, Pluto has a heart! Scientists named it Tombaugh Regio, after Clyde Tombaugh, the man who discovered Pluto in 1930. It’s one of the strangest and most unexpected features ever found in the solar system.
But Pluto isn’t just a lonely ball of ice. It has five moons, and one of them, Charon, is almost half the size of Pluto itself. In fact, Pluto and Charon are so close in size that they don’t orbit the way most planets and moons do. Instead, they move around a shared center of gravity, almost like a pair of dancers spinning around each other. This is different from how Earth and the Moon move together. If you could stand on Pluto and look up at Charon, you’d see a giant moon that never changes position in the sky. It would just stay in one spot while Pluto rotated underneath it.
Because Pluto is so far from the Sun, it takes a very long time to complete just one trip around it. A year on Pluto is about 248 Earth years long. That means that since the time Pluto was discovered, it still hasn’t even finished one full orbit! Seasons on Pluto last for decades, and when it’s winter, the atmosphere actually freezes and falls to the ground like snow. When the planet moves closer to the Sun, some of that frozen gas turns back into an atmosphere, but it’s nothing like the one we have on Earth. The air around Pluto is incredibly thin, and it’s mostly made of nitrogen, just like the ice on its surface.
People have always been curious about Pluto, but because of its small size and its unusual orbit, it didn’t quite fit in with the other planets. It was much smaller than Mercury, even smaller than some of the moons of Jupiter and Saturn. It also had an orbit that was more tilted and stretched out than the round, steady paths of the planets. That’s why, in 2006, scientists decided that Pluto wasn’t a planet after all. They made a new category called “dwarf planets” for objects like Pluto—things that are round and orbit the Sun but don’t meet all the rules for being a planet. Some people were upset about this change, and even today, there are scientists who argue that Pluto should still be called a planet.
Pluto may be small, but it has taught scientists a lot about the solar system. The discovery of Pluto led to the discovery of the Kuiper Belt, which turned out to be full of other icy worlds. It also helped scientists understand that the solar system is even more complicated and interesting than they once thought. And because of New Horizons, people now know more about Pluto than ever before. It’s no longer just a tiny dot in space—it’s a world full of surprises, with glaciers, mountains, and an atmosphere that comes and goes.