A super-Earth is a very big planet that's much larger than Earth, but not quite as big as the gas giants like Jupiter and Saturn. Imagine a big ball, like a soccer ball, that's much bigger than your head but not as big as a beach ball. That big ball is like a super-Earth, which is much bigger than the Earth we live on.
These planets are called "super-Earths" because they're much bigger than our Earth, but still have solid surfaces like we do. But they're not exactly like our Earth because they could have very different environments, such as very hot or very cold temperatures or even different types of atmospheres. Scientists are still trying to understand these planets and what they might be like.
Some super-Earths are thought to be covered in lava, while others might have a lot of water, or even ice. Some may have very thick atmospheres with lots of gases, while others may have almost no atmospheres at all.
Scientists have discovered many super-Earths by using telescopes to observe the light from stars. They can detect when a planet passes in front of its star, causing a tiny dip in the star's brightness. By studying these dips, scientists can figure out the size and other characteristics of the planet.
So, to sum up, a super-Earth is a really big planet that's much larger than our Earth, but not as big as the gas giants. They're called "super-Earths" because they have solid surfaces like our Earth, but they can be very different from our planet in terms of temperature and atmosphere. Scientists are still learning more about these unique celestial bodies.