The Alien Observatory: “It’s Just Too Damn Quiet in the Local Universe” (Today’s Top Space Headline)

“Now that we know that the Earth is a latecomer, and believe the foundations of life have the power to take hold quickly, Fermi’s paradox is more puzzling than ever. In the evocative words of physicist Adrian Kent: It’s just too damn quiet in the local universe.”

One summer’s day in 1950, the great Italian-American physicist Enrico Fermi was having lunch with the physicists Edward Teller, Emil Konopinski, and Herbert York at Los Alamos when the conversation turned to a flood of recent UFO sightings all over the United States. There were also, coincidentally, reports of trashcans going missing in New York City at the time. A New Yorker cartoon connected the dots and accused interstellar visitors of the misdeed. In the relaxed atmosphere of that lunchtime conversation, Fermi remarked that the New Yorker’s solution, by proposing a single common cause of two independent empirical phenomena, was in the very best traditions of scientific methodology.

The lunchtime chat stayed on the topic of ET, continues Milan Ćirković, a senior research associate at the Astronomical Observatory of Belgrade and an assistant professor in the Department of Physics at the University of Novi Sad in Serbia and Montenegro, in While they obviously didn’t take seriously the reports of flying saucers, Fermi and his companions began to earnestly discuss things like interstellar—and even superluminal—travel. Then, after some delay—and, one might imagine, in the midst of some tasty dish—Fermi allegedly asked his famous question. Where, indeed, is everybody? Where are the extraterrestrials?

The Milky Way galaxy is about 100,000 light-years from edge to edge, Fermi reasoned, which means that a star-faring species would need about 10 million years to traverse it, even if moving at a very modest velocity of 1 percent of the speed of light. Since the galaxy is more than a thousand times older than this, any technological civilization will have had a lot of time in which to expand and colonize the whole galaxy. If one species were to fail in this endeavour, another wouldn’t. Consequently, if intelligent species were out there in any appreciable numbers, they would have been here already. And yet, we do not see them on Earth or in the solar system. For Fermi and many thinkers since, this constituted a paradox.

The volume of scientific literature that Fermi’s paradox has inspired testifies to its serious and provocative nature. When you consider fiction and movies, it’s clear that Fermi’s paradox has become an important part of contemporary culture, challenging us to think more deeply about our place in the cosmos.

But, still, the paradox remains incompletely understood by science, incompletely digested by popular culture, and even actively resisted or deliberately ignored. In this sense, it has become a type of Rorschach test: Our attitudes to the paradox tell us something about ourselves.

The strong version of Fermi’s paradox (it is only proper and intellectually honest to tackle the strongest version of any particular scientific problem) doesn’t just ask why there aren’t aliens here on Earth. It also asks why we don’t see any manifestations or traces of extraterrestrial civilizations anywhere in our past light cone—that is the whole volume of space and time visible to us, extending billions of years into the past, to the epoch of earliest galaxies.

The strong Fermi’s paradox became even stronger, so to speak, in 2001, with the work of Charles Lineweaver and collaborators on the age distribution of terrestrial planets in the Milky Way. His calculations show that Earth-like planets in our galaxy began forming more than 9 billion years ago, and that their median age is 6.4 ± 0.9 billion years, which is significantly greater than the age of the Earth and the solar system. This means that a large majority of habitable planets are much older than Earth. If we believe that humans and the planet we live on are not particularly special compared to other civilizations on other planets, we would conclude that the stage of the biosphere and technology on other occupied planets must be, on average, older than the corresponding stages we see on Earth. If we humans are now on the cusp of colonizing our solar system, and we are not much faster than other civilizations, those civilizations should have completed this colonization long ago and spread to other parts of the galaxy.

We presume ourselves to be so special that the question “Where is everybody as complex and important as ourselves (or more)?” cannot be taken seriously.

Another piece of recent science amplifies Fermi’s paradox even further. Geochemical and paleobiological research has recently confirmed that the oldest traces of living beings on Earth are at least 3.8 billion years old, and probably as old as 4.1 billion. The Earth itself is only 4.5 billion years old. While the mechanism of abiogenesis (the origination of life) is still largely unknown, the evidence of abiogenesis occurring early in the Earth’s history seems incontrovertible. The consequences are rather dramatic: If life is quick to form after its host planet has formed, we get good probabilistic support for the existence of simple life on many planets in the Milky Way, and potentially complex life on some of them.

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