The temperature of the ice and snow planet is as low as MINUS 17 degrees Celsius. Why do scientists think there is life?

Is there life on other planets besides the Earth? I believe many friends will take a positive attitude. After all, the universe is so big. If life on earth is not set and the universe is not virtual, then life on earth should be very common, although we haven't found them yet.

In fact, part of the reason why scientists couldn't find extraterrestrial life before was that scientists initially used the Earth as a reference sample, and thought that if there was life on a planet in the universe, it should probably be located in the habitable zone of a star like the Earth, with proper temperature, abundant water resources and a thick atmosphere. However, there are millions of kinds of life on the earth (according to statistics, at least hundreds of millions of kinds of life have been born on the earth since the birth of the first life on the earth). Therefore, life forms in the universe should also be different.

For example, before looking for life, we always focus on terrestrial planets, especially those in habitable areas, and turn them into "super earth" or "second earth". However, with the development of human science and technology in recent years, the more scientists know about the universe, the more they pay attention to other planets that have never been noticed before. For example, satellites, in fact, in our solar system, there are several satellites that may have life.

Europa, in particular, is highly praised by scientists. If there is another planet in the solar system besides the earth that is most likely to have life (even exists), then it must be Europa. Why do scientists think so?

As an "ice and snow" planet with a surface temperature of about 163 degrees below zero and a polar temperature of more than 2 degrees below zero, scientists believe that there is a warm ocean about 15 kilometers under the thick ice of Europa, where life may have been born, and at least 3 million tons of fish live in it. The reason why scientists are so artificial is not only because Europa may have a larger liquid ocean than the earth, but also because Europa has an atmosphere, the main component of which is oxygen.