Do aliens exist? A new study raises the possibility that intelligent life is much more common than scientists previously thought!

Scientists have long thought that the existence of humans (Earth’s intelligent life-forms) came about due to a rare and lucky set of conditions and events. This is based on a 1983 theory by a scientist named Brandon Carter. Carter started with the fact that Earth is about 4.6 billion years old, but humans did not exist until about 200,000 years ago. This led him to believe that humans could develop only after a few key conditions were met. And even after that, Carter believed, it took a long time for humans to appear. 

Carter believed that it takes so long for intelligent life to evolve that on most planets, the host star, which is needed for life, would have burned out before that could happen.  Luckily for us, we evolved while our Sun was still young—only a few billion years old.

But a team of scientists at Penn State University say they don’t believe it takes a long time for intelligent life to evolve once a planet is able to support it. In fact, they believe that if conditions are right, intelligent life will evolve. And that means it’s possible that intelligent life exists on any planet where conditions are right.

Rocky planets that are Earth sized are most likely to be able to support life. Scientists believe there are about 1 billion Earth-sized planets in our galaxy alone, and many of them are likely to be rocky. That doesn’t mean intelligent aliens are living on every one of those planets. But if the Penn State study is correct, it’s possible we’re not alone.