Nope: Could UFOs really exist and how would they fly?

Think of an alien spaceship and it’s likely that the first image to come to your mind is a flying saucer, possibly darting across the sky in grainy footage, or abducting a farmer in the interests of little green men.

It is such an enduring idea, in fact, that it has survived all the way until Nope, the new film from Jordan Peele, which is set around a ranch that is being terrorised by a UFO. But how feasible are the existence of flying saucers? And even if they did exist, would they be able to fly?

“There have been attempts to develop ships that looked like flying saucers,” says astronomer Colin Stuart, author of books such as How To Live in Space. “In the 1950s, the US Air Force were working with a [now defunct] Canadian company called Avro to build the VZ-9 Avrocar. The point of it was that taking off and landing on a runway is quite restrictive, whereas a flying saucer could take off and land vertically. It would be more flexible.”

According to declassified documents, the designers of the Avrocar had hoped to achieve vertical take-off and landing using propulsion jets along the rim of the disc, which would be fed air from a jet engine in the centre, to control and stabilise the ship.

They also believed that the aircraft could reach a top speed between Mach 3 and 4, climb a ceiling of 100,000 feet and have a maximum range of about 1000 nautical miles. In reality, however, various iterations of the Avrocar struggled to get more than a few feet off the ground, and couldn’t fly faster than 35 MPH. Its central jet engine was also monstrously loud and subjected the pilot to intense temperatures.

“It’s not as aerodynamic a shape as say, your classic fighter jet with the point at the front that’s tearing through the air,” says Stuart. “You see a lot of flying saucers in fiction where the propulsion seems to be underneath the ship. But whichever way you’re firing out of the nozzle, you’re going the other way. So if you’re trying to go through the air, you need to put your propulsion in a very small area around the rim. But how do you then put that propulsion system in? Your space is limited with that design.”

In 2008, there were reports of a small, unmanned saucer-like design that would cover the craft in electrodes that could ionise air to create plasma. That plasma would then be accelerated by a magnetic field to generate lift. “That’s the most likely way of doing it,” says Stuart.

“Because we do that already: we have ion drives which we use in normal spacecraft. The Dawn mission that went to Ceres and Vesta, the two asteroids, was the first mission to go into orbit around two solar system bodies in the same mission. And part of the reason they could do that was that the gravity of these two asteroids was quite small, but part of it was that the craft was nimble because it had an ion drive. That propulsion is similar to how you would use flying saucers.”

As for the question of whether an alien species has cracked the design themselves, and are flying around our atmosphere for the hell of it, Stuart is sceptical.

“If you think about UFO sightings,” he says, “why did they only start really kicking off in the 40s and 50s? Because that’s when we started building military jets that could go really fast. That’s not a coincidence. There weren’t that many UFO sightings before the age of flight. It also isn’t a coincidence that the sightings mostly come in countries that have developed militaries, or that the rough size of a UFO is about the same size to fit a human inside. The idea that an alien would be exactly the same size as a human is unlikely. Because their planet might be very different to ours. If their planet had stronger gravity they’d be shorter, if their planet had weaker gravity, they’d be taller.”

And even if aliens had come up with working flying saucers, the chances of them having travelled across interstellar space in them to visit us are slim.

“You would need two different means of propulsion,” says Stuart. “You can use the plasma ion drive in space. We did that with Dawn. But the issue is if you wanted to get across from another star system to our star system, the amount of acceleration that you can get from an ion drive is quite low. If you wanted to travel meaningful distances, you would struggle. Instead, I think you would need two systems: a kind of cruiser, or rocket, that would transport the flying saucers into the solar system, and then you could manoeuvre down into the Earth's atmosphere.”

Given how much that sounds like an invading fleet, the only thing we have to say to that is: Nope.