Do aliens exist? We studied what scientists really think

News reports about the likely existence of extraterrestrial life and our chances of detecting it tend to be positive. We are often told that we could find out at any time. Discovering life beyond Earth is “only a matter of time”, we were told in September 2023. “We are close” was the headline in September 2024.

It’s easy to understand why. Titles like “We’re probably not close” or “No one knows” aren’t very clickable. But what does the relevant expert community really think when considered as a whole? Are optimistic predictions common or rare? Is there even a consensus? In our new article, published in Natural astronomywe discovered it.

From February to June 2024, we conducted four investigations into the likely existence of basic, complex, and intelligent extraterrestrial life. We sent emails to astrobiologists (scientists who study extraterrestrial life), as well as scientists in other fields, including biologists and physicists.

In total, 521 astrobiologists responded and we received 534 non-astrobiologist responses. The results reveal that 86.6% of astrobiologists surveyed responded “agree” or “strongly agree” that it is likely that extraterrestrial life (at least of a basic type) exists somewhere in the world. the universe.

Less than 2% disagree, and 12% remain neutral. So, based on this, we could say that there is a solid consensus that extraterrestrial life, in one form or another, exists somewhere.

Scientists who were not astrobiologists mostly agreed, with an overall agreement score of 88.4%. In other words, we cannot say that astrobiologists tend to believe in extraterrestrial life, compared to other scientists.

When we turn to “complex” extraterrestrial life or “intelligent” aliens, our results were 67.4% agreement and 58.2% agreement for astrobiologists and other scientists, respectively. So, scientists tend to think that extraterrestrial life exists, even in more advanced forms.

These results are all the more significant as the disagreement is low for all categories. For example, only 10.2% of astrobiologists disagree with the statement that intelligent aliens probably exist.

Optimists and pessimists

Are scientists just speculating? Usually, we should only take note of a scientific consensus when it is based on evidence (and lots of evidence). Since there is no good evidence, scientists can guess. However, scientists had the option to vote “neutral”, an option that was chosen by some scientists who felt it was speculation.

Only 12% chose this option. There is actually plenty of “indirect” or “theoretical” evidence for the existence of extraterrestrial life. For example, we now know that habitable environments are very common in the universe.

We have several in our own solar system, including the subterranean oceans of the moons Europa and Enceladus, and probably also the environment a few kilometers below the surface of Mars. It also seems relevant that Mars was highly habitable, with lakes and rivers of liquid water on its surface and a substantial atmosphere.

It is reasonable to generalize from here to a truly gargantuan number of habitable environments across the galaxy and wider universe. We also know (since we’re here) that life can arise from non-life – it did happen on Earth, after all. Although the origin of the first simple forms of life is poorly understood, there is no compelling reason to think that it required astronomically rare conditions. And even if it did, the probability of life beginning (abiogenesis) is clearly non-zero.

This may help us see the 86.6% agreement in a new light. This may not actually be a surprisingly strong consensus. It may be surprising weak consensus. Consider the numbers: there are more than 100 billion galaxies. And we know that habitable environments are everywhere.

Let’s say there are 100 billion billion habitable worlds (planets or moons) in the universe. Suppose we are so pessimistic that we think the chances of life starting on any given habitable world are one in a billion billion. In this case, we would still answer “agree” to the statement that it is likely that extraterrestrial life exists in the universe.

Thus, optimists and pessimists should all have responded “agree” or “completely agree” to our survey, with only the most radical pessimists on the origin of life disagreeing.

With this in mind, we could present our data in another way. Suppose we discard the 60 neutral votes we received. Perhaps these scientists thought they were speculating and didn’t want to take a position. In this case, it makes sense to ignore their votes. That leaves 461 total votes, with 451 for agree or strongly agree. We now have an overall agreement percentage of 97.8%.

This decision is not as illegitimate as it seems. Scientists know that if they choose “neutral,” they can’t be wrong. So it’s the “safe” choice. In research, we often talk about “satisfactory”.

As geophysicist Edward Bullard wrote in 1975 when wondering if all the continents were once united, instead of making a choice, “it is safer to keep quiet,… to sit on the fence and ‘wait in statesmanlike ambiguity for additional data’. Not only is remaining silent a safe choice for scientists, it means that scientists don’t need to think too much. easy choice.

Finding the right balance

What we probably want is a balance. On the one hand we have the lack of direct empirical evidence and the reluctance of responsible scientists to speculate. On the other hand, we have evidence of other kinds, including the truly gargantuan number of habitable environments in the universe.

We know that the probability of life beginning is non-zero. Perhaps 86.6% agreeing, with 12% neutral and less than 2% disagreeing, is a sensible compromise, all things considered.

Perhaps – given the satisfaction problem – whenever we present such results, we should present two results for overall agreement: one with the neutral votes included (86.6%), and one with the neutral votes ignored (97.8%). Neither outcome is the unique and correct outcome.

Each perspective addresses different analytical needs and helps avoid oversimplification of data. Ultimately, communicating both numbers – and being transparent about their contexts – is the most honest way to represent the true complexity of the answers.

This article is republished from The Conversation under a Creative Commons license. Read the original article.