Are we alone in the universe? Maybe not. Scientists think there could be life on other planets.
Most parts of the world have some form of life. You can find life in frozen Antarctica and in the driest, hottest deserts. For example, there are penguins and seals in Antarctica and camels in the desert. They all need water in order to survive. Therefore, scientists are looking for other planets that might have water and living creatures. Maybe there is even intelligent life on other planets.
Scientists are studying Europa, one of Jupiter’s moons. Europa is a little smaller than our moon and is covered in ice. Astronomers think that there may be an ocean of water under the ice, and if so, there may be strange sea creatures swimming around deep underwater. What kind of animals could live there? What might they look like? Would they look like our sea life? Or would they look like a mixture of our animals: with the bodies of fish but heads like those of tigers? Or with the face of a frog and the body of an elephant? We simply don’t know.
Scientists are also studying Mars. Astronomers can see dry riverbeds and ridges that look like ocean shores on the planet. This means that there used to be rivers and oceans. Mars may have been warm and wet millions of years ago. There could have been something living there. Fossils could also be found on Mars. But now, scientists know that Mars is very cold and dry, with no present possibility of life.
Furthermore, scientists have sent a radio message to the stars, very far from Earth. Their hope is that someone out there, an alien maybe, can understand the message about life on Earth. If it is possible, it would take the message 25,000 years to get to the stars, and another 25,000 years to get a message back. Therefore, even if the aliens send us a reply, we will have passed away. However, maybe our descendants will get the message.
[Source: 100 things you should know about space]