One in five Americans believes that aliens not only exist but have visited Earth. But if aliens do exist, where are they?
That’s the crux of the Fermi Paradox. It’s scientifically probable that, given the size and age of the universe, alien civilizations existed at some point. And yet we’ve never seen conclusive proof of their existence.
That seeming contradiction has puzzled the greatest scientific minds for decades. We’re no closer to an answer now than we were in 1950, when Enrico Fermi first posed his question.
If life–any life, not just intelligent beings–exists in our Solar System, scientists have a good idea where it will turn up. The likely candidates are “ocean worlds” like Jupiter’s moon Europa. NASA has determined that liquid water might exist on the moon beneath thick layers of ice.
The conditions there might be similar to those in the deep ocean, where thermal vents allow life to flourish. We may get an answer sooner rather than later. NASA plans to launch a mission to Europa in 2024.
Even if life does exist on Europa, it’s not going to be the kind that builds spaceships and travels the stars. For that, we need to look farther into space.
Exoplanets are planets that orbit stars other than our own. While it might seem like a no-brainer that the stars we see in the night sky could have planets, it wasn’t until relatively recently that we had the technology to detect Earth-sized planets.
Big planets (the size of Jupiter or bigger) can cause their stars to wobble slightly, offering indirect proof that they exist even if we can’t see them directly. But it wasn’t until the 2009 Kepler mission that we were able to find planets in what scientists call “the habitable zone.” That’s the right size, composition, and distance from their sun to support life as we understand it.
If life exists out there in a form that we can recognize, it’s probably on one of these exoplanets. However, these planets are so far away that travel between them might not ever be possible. Unless….
Roger Penrose, a physicist and mathematician who worked with Stephen Hawking to develop a model of black holes, had an idea about how alien civilizations could travel between the stars.
The problem is one of fuel. A spaceship simply can’t carry enough fuel to cover those distances; at a certain point, the weight of the fuel itself cancels out the energy it could produce.
That’s where black holes come into play. Penrose predicted that an advanced alien civilization could use the outermost edge of a black hole to gain energy. Penrose’s theory is based on light waves and requires technology far advanced from ours to prove.
But just this week, scientists managed to reproduce the theoretical amplifying effect with sound waves instead of light waves.
“It’s strange to think that we’ve been able to confirm a half-century-old theory with cosmic origins here in our lab in the west of Scotland, but we think it will open up a lot of new avenues of scientific exploration. We’re keen to see how we can investigate the effect on different sources such as electromagnetic waves in the near future,” Professor Daniele Faccio, who coauthored the paper on the experiment, said.
While we’re still a long way from proving that life exists out there, the pace of scientific breakthroughs in the last 50 years suggest that we could learn the truth in our lifetimes.