The likelihood of life beyond Earth

Do you believe in aliens? This is a question that people often ask each other - but you can only discuss assumptions, because we have no proof that humanity is not alone. In such a situation, statistics come to the rescue. David Kipping, assistant professor of astronomy at Columbia University, published his new researchAn objective Bayesian analysis of life’s early start and our late arrival. In it, he calculated the probability of the existence of life outside the Earth - including a reasonable one.

He considered four possible situations:

1. Life is common, and just as often is it intelligent.
2. Life is common, but intelligent life is rare.
3. Life is rare, but predominantly intelligent.
4. Life is rare, and intelligent life is even rarer.

As Kipping explains, the technique is similar to odds. Searching for new data and rechecking old ones increases the accuracy of assessing the probability of an event. In his research, he worked with each of the four probabilities, using a formula based on our knowledge of how life appeared on Earth and how it became intelligent.

The results were surprisingly optimistic. The chances of existence of life outside the Earth are high enough. Considering that Earth-like planets are not uncommon (with a solid surface, at a moderate distance from their stars and with enough moisture), the probability is at least 9: 1 in favor of the existence life.

On the other hand, intelligent life is no longer so likely. According to statistics, the chance is about 3: 2 - still in favor of life. At the same time, Kipping notes that even on Earth, the likelihood of human evolution from the point of view of statistics was unlikely - but, obviously, it did happen.

In the article, the author notes: “The analysis cannot provide any guarantee, these are only statistical probabilities based on what happened here on Earth. However, it is encouraging how likely it is that the universe is teeming with life. "

It is important to understand that this is not proof of the existence of aliens. It just goes to show that mathematically, we are probably not alone in the universe.