The year is 1950. Physicist Enrico Fermi is having lunch with colleagues outside Los Alamos National Laboratory in New Mexico. He looks up at the sky and asks, “Where is everybody?” He is wondering about space aliens. This question, known as the Fermi paradox, has puzzled scientists for decades. Despite many reports, there is still no solid evidence of alien life or technology in our solar system or beyond.
One reason for the lack of evidence could be that aliens simply do not exist. Another possibility is that our methods of searching for them are not thorough enough. This concept of sampling depth refers to how well we can conduct a search. Fermi’s question forces us to consider these two options: either aliens are not near Earth, or our current search methods are inadequate.
This dilemma is a common challenge in science. Determining when our sampling depth is enough to detect an effect, especially when that effect is not well understood, can be tricky. Just like astronomers faced skepticism when searching for exoplanets around other stars, questioning the existence of aliens near us requires a critical examination of our search methods.
When we think about the vastness of space, the idea of finding interstellar travelers can seem unnecessary. Our closest star, Proxima Centauri, is about four light-years away. The Milky Way galaxy is about 100,000 light-years in diameter. The chances of an alien spaceship crossing paths with us in both space and time seem slim. Maybe the Fermi paradox isn’t so paradoxical after all.
However, in terms of cosmic time, our galaxy is not as vast as it seems. The Milky Way is around 13 billion years old, while our solar system is only 4.5 billion years old. This means that many planets in our galaxy are much older than Earth. If technological life arose on one of these planets billions of years ago, there has been plenty of time for them to develop interstellar probes. Recent simulations show that these probes could spread across the galaxy over time.
So, where are these probes or alien civilizations? To answer this question, we must reconsider our sampling depth. Have we overlooked something in our search for interstellar spacecraft? History is filled with examples of discoveries made when researchers expanded their ideas of what was detectable. For instance, the existence of microbes was proposed before they could be observed under a microscope.
In 2022, NASA commissioned a study to determine if our current surveillance systems could detect unidentified anomalous phenomena, potentially alien spacecraft. The study found that our current satellites lack the spatial resolution to detect small objects like UAPs. This suggests that there are limits to our sampling depth when it comes to monitoring Earth’s atmosphere.
The prevailing assumption in the scientific community is that alien spacecraft would emit noticeable signals if they were nearby. However, we may need to consider the possibility that alien technology could be more subtle and efficient than we imagine. Just as advances in technology on Earth have led to more compact and efficient devices, alien civilizations may have developed advanced spacecraft that are not easily detectable.
So, when Fermi asked, “Where is everybody?” maybe he should have been questioning why we haven’t found any loud, obvious indicators of aliens. Perhaps alien spacecraft are nearby, and we just haven’t looked in the right way yet. This reevaluation of our sampling depth could lead to new insights and discoveries about the potential existence of extraterrestrial life.
