1What are Exoplanets?
Beyond the eight planets in our own solar system, there is a whole universe filled with mysterious worlds called exoplanets. Since the 1990s, astronomers have used powerful telescopes to discover over 5,000 of these far-off worlds orbiting different stars in the Milky Way! These planets are incredibly diverse. Some orbit two suns at once, just like the planet Tatooine in movies, while others are so close to their stars that they are covered in molten lava. There are even worlds made of solid diamond and others that are giant balls of gas much larger than Jupiter.
2The Search for Liquid Water
One of the most exciting things scientists look for is the "Goldilocks Zone." This is a special area around a star where the temperature is just right—not too hot and not too cold—for liquid water to exist on a planet's surface. Because water is a key ingredient for life on Earth, finding it on an exoplanet is a big clue that tiny creatures or alien plants could live there! By using high-tech tools to study the light passing through a planet's atmosphere, space experts look for signs of oxygen, carbon dioxide, or methane, which are all hints that something might be breathing or growing millions of miles away.
3Super-Earths and Hot Jupiters
Many of the alien worlds we find are quite different from our home. Scientists often find "Super-Earths," which are rocky planets bigger than Earth but smaller than Neptune. They also find "Hot Jupiters," which are massive gas giants that orbit so close to their sun that a whole year there only lasts a few Earth days! Every new exoplanet we find helps us understand how our own solar system was formed and what secrets the rest of the galaxy is hiding. As technology gets better, we get closer to answering the biggest question of all: are we alone in the universe?
