{"id":219847,"date":"2022-12-18T22:34:53","date_gmt":"2022-12-18T20:34:53","guid":{"rendered":"https:\/\/osr.org\/?p=219847"},"modified":"2023-07-24T14:04:47","modified_gmt":"2023-07-24T12:04:47","slug":"what-is-the-fermi-paradox","status":"publish","type":"post","link":"https:\/\/osr.org\/en-uk\/blog\/astronomy-uk\/what-is-the-fermi-paradox\/","title":{"rendered":"What Is the Fermi Paradox?"},"content":{"rendered":"

An estimated 200 billion galaxies are in the observable universe, each containing billions of stars. We’re constantly finding new planets orbiting these stars, some of which show signs of being habitable. But despite all of this, we still have no evidence of life beyond Earth. So, where is everyone? Physicist Enrico Fermi posed this question, and we’ve been trying to find an answer ever since. But what is the Fermi paradox?<\/p>\n

What Is the Fermi Paradox?<\/span><\/h2>\n

With as many as 200 billion trillion<\/a> stars in the universe, life should be everywhere. And yet there isn’t a single shred of evidence that life exists anywhere other than Earth. The Fermi paradox essentially asks the question – why we haven’t found anyone else? Just because we haven’t found extraterrestrial life yet doesn’t mean it isn’t out there, but maybe some of the below points are why we’re still looking.<\/p>\n

The Great Filter<\/span><\/h2>\n

For life to spark into existence from non-living organic matter, a series of conditions and events need to fall into place, starting with a habitable location in a suitable star system. Next, life must be able to evolve into increasingly more complex forms, starting from single-cell organisms. The Great Filter<\/a> suggests that one of the required steps to reach intelligent life may be highly improbable. This would mean that complex life is rare.<\/p>\n

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Intelligence Is Rare<\/span><\/h2>\n

Even if life is common throughout the universe, maybe intelligent life isn’t. Complex life flourishes across our planet, yet only a handful of species, including humans, dolphins and apes, exhibit intelligence. Further still, only humans possess the intelligence that could be detected from other star systems, for instance, from emitting radio signals.<\/p>\n

Lack of Technological Advancement<\/span><\/h2>\n

A nearby star could play host to a world inhabited by intelligent life, but they aren’t evolved enough to make themselves known. Considering our history, we first sent radio transmissions in 1897 \u2013 practically yesterday compared to our planet’s age of 4.5 billion years! If a nearby civilisation is currently in a period like our dark ages, it could be hundreds of years before they make enough noise for us to hear them.<\/p>\n

Too Technologically Advanced<\/span><\/h2>\n

Or the exact opposite could be true! If a civilisation lives on a planet orbiting an older star, such as the 13.4-billion-year-old HD 164922<\/a>, it could have had billions of years to advance its technology. In such a situation, it’s almost certain that their level of technology would be far beyond anything that we could comprehend, just as an ape wouldn’t know where to start with a radio telescope!<\/p>\n

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Distance and Time Limitations<\/span><\/h2>\n

Given the size of our galaxy and the distance between stars, it could well be that any neighbouring civilisations are too far away for communication. A message sent to Proxima Centauri<\/a>, the nearest star to Earth after our own Sun, would take 4.25 years to arrive. A simple exchange of messages with any potential inhabitants of the star system would therefore take 8.5 years. If our potential galactic neighbours are in a more distant part of the galaxy, it could take thousands of years to say hello to each other \u2013 during which time, one of both civilisations could become extinct.<\/p>\n

Self-destruction<\/span><\/h2>\n

It’s fair to say that, over the years, we haven’t made things easy for ourselves. War, nuclear weapons, climate change, and pandemics have all affected us. It may well be that intelligent life is doomed to destroy itself not long after gaining the ability to do so. While we don’t know if other life forms share these self-destructive traits, it could explain why no one else is around.<\/p>\n

Aggressive Aliens<\/span><\/h2>\n

Rather than destroying themselves, it could also be the case that an alien civilisation wants to destroy the life they come across in other worlds. There are several reasons why they might do this:<\/p>\n