Humans have been actively searching for alien civilizations through the SETI—Search for Extraterrestrial Intelligence—project for about 60 years. So far, despite millions of dollars in investment and diligently searching the skies for signals, humanity has come up with bupkis. But Lisa Grossman at ScienceNews reports that our expectations might be too high; a new study suggests we haven't exactly taken a deep dive when it comes to hunting for other-worldly life forms. In fact, a new study says we've really only examined a "hot tub" worth of our cosmic ocean.
The research attempts to address the Fermi Paradox, a casual question supposedly asked by famed Italian physicist Enrico Fermi at a lunch in 1950. The query Fermi posed follows this general train of thought: If the universe is so huge and alien species have had over 13 billion years to evolve and develop technology, why haven’t we seen signs of them? If there are aliens out there, why haven’t we picked up a single broadcast, greeting or other “technosignatures?” Is is because we haven’t looked hard enough or in the right places, or does alien life simply not exist?
Back in 2010, former SETI director Jill Tarter set out to answer that question, reports Eric Mack at CNET. After analyzing the vast area that needed to be searched and the efforts made up to that point, she concluded that humanity’s search for signs of alien life was the equivalent of looking at a glass of water to determine if there were fish in the ocean.
Astronomer Jason Wright of Penn State University and his colleagues decided to update Tarter’s research in a new study submitted to the The Astronomical Journal. To understand just how much of space we’ve sifted through, the researchers calculated the amount of space that our telescopes and other signal-detecting devices have analyzed so far. Building on Tarter’s work, they added in new channels where might find alien signals and included data from more recent studies like the Breakthrough Listen Initiative, which is surveying the million stars closest to Earth and 100 nearest galaxies. They then compared all of that data with the amount of searching astronomers estimate humans need to do before before concluding there is intelligent life in the universe.
Where Tarter found a glass of water, Wheeler and his co-authors found we've examined a cosmic Jacuzzi-worth of space. Better, but still barely a start.
“If you looked at a random hot tub’s worth of water in the ocean, you wouldn’t always expect a fish,” Wright tells Grossman at ScienceNews.
In a more precise analogy, the researchers explain that thus far astronomers have looked at the equivalent of about 7,700 liters of water in a 1.335 billion trillion liter ocean.
While finding an alien signal in that vast quantity of space seems daunting or even impossible, the researchers give some hope. In the paper, they say that while the “needle in a haystack” analogy is useful, we may be looking for lots of potential needles in the haystack. The only reason we would need to go through the entire enormous haystack is if we don’t find any needles.
“Because technological life might spread through the Galaxy, or because technological species might arise independently in many places, we might expect there to be a great number of needles to be found,” they write in the paper.
And there's reason to hope that our search will begin to accelerate soon.
“We’re finally getting to the point today … that we have a chance of finding something, depending on how much there is to find,” Wright tells Grossman.
That’s because, as Tarter pointed out in a NASA speech on the subject last week, a new generation of telescopes going live soon will help us scan more of the sky more efficiently, and improved artificial intelligence will help us pinpoint just which cosmic hot tubs we should be looking in. In fact, earlier this year Tarter said she believed that humanity would find signs of extraterrestrial life by the end of the century.