What are rogue planets?

Rogue planets are planets that don’t have a home near a star, like Earth does near the Sun.

Imagine you're playing in your backyard, and all of a sudden, you take off running, fast, really fast, and leave your house behind. You’re still on Earth, but you’re not near any house or yard anymore. That’s kind of what happens to rogue planets.

Most planets, like Earth, are born in a solar system with other planets and a star. But sometimes, when things get messy, maybe another planet crashes into them or they get pushed too hard, they break free from their home and start traveling all by themselves through space.

A rogue planet is like a kid who leaves the playground to wander around the city alone. It doesn’t have a star to shine on it, so it gets really cold, sometimes colder than the coldest winter day you’ve ever felt! But even though it’s all by itself in space, it’s still a real planet, just traveling through the universe like a lonely explorer.