Scientists are debating multiple options to deal with an asteroid that has a slim chance of hitting Earth in 2032.

Under debate are options including hitting the asteroid, designated 2024 YR4, with a nuclear weapon, British astronomer Dr David Whitehouse told Yahoo News.

A key challenge is the lack of time, with the asteroid - which scientists say has a 2% chance of striking the planet - already receding from Earth as its trajectory is monitored by increasingly larger telescopes.

By May it will be out of view, headed towards Jupiter and set to return in December 2032.

Scientists are debating different options including using a powerful laser; a nuclear weapon; or ‘ramming’ it with a spacecraft, Whitehouse explains. However, there are practical problems around a number of these.

The European Space Agency (ESA) estimates that the asteroid is between 40-100 metres wide. That would potentially make the space rock’s width similar to the height of Big Ben in London, which is 96 metres high, and its impact could cause damage similar to a nuclear explosion.

Nuclear strike

Any plan to use a nuclear weapon against the asteroid will not involve an astronaut mission, as portrayed in the 1998 Bruce Willis blockbuster Armageddon.

Lindley Johnson of NASA has previously said of such an approach: "If you've seen those movies, they're completely bogus. That's not how we would use a nuclear explosive device to do this at all."

Instead, a nuclear weapon would be used to nudge the space rock into a different orbit.

The ‘nuclear option’ would be most likely to be used with larger asteroids more than half a mile in diameter.

Johnson said: "We just need to change that speed by maybe a couple of centimetres per second. If we do that several years in advance, the change that occurs in the orbit as it comes around several years later to that impact point — the change in velocity will cause it to arrive early or late to the impact point. That's all we need."

In September 2024, physicists at the Sandia National Laboratories US government facility said the most efficient way to prevent potentially dangerous asteroids from damaging or even obliterating Earth may involve a coordinated nuclear response.

"“The trick is to use just enough force to redirect the flying rock without splitting it into several equally deadly subsections advancing toward Earth,” researchers said.

But when it comes to YR4, most astronomers are already ruling out a nuclear weapon, said Whitehouse.

“A nuclear impact probably would work, but you've got to get it there, first of all," he said." From what I understand from various people, nobody wants to put a nuke in space really: there are all sorts of international treaties about putting nukes in space. There's a lot of opposition."

Laser strike

Another approach - which also sounds like something straight out of Hollywood - would be to target the asteroid with a large laser in Earth's orbit. But rather than blasting the asteroid out of existence, the laser would evaporate its surface, altering the asteroid’s trajectory.

Qicheng Zhang of the University of California, Santa Barbara submitted a paper showing that a one gigawatt laser, firing for a month, could move an asteroid out of Earth orbit successfully.

However, Whitehouse said that developing the untested technology in the time before YR4 returns would be too challenging.

He told Yahoo News: "It’s too far away, over a million miles, would we actually hit it with enough energy? We haven't got all that strong lasers that are publicly known. You've also got the tracking problem - you'd never be able to track it.”

Impactor

By far the most likely option to be used is an ‘impactor’ - a spacecraft that would be flown into the asteroid to knock it off course, said Whitehouse.

NASA and the ESA have conducted research into how the trajectory of an asteroid can be changed by ramming it with a spacecraft.

In September 2022, NASA's Double Asteroid Redirection Test (DART) mission impacted the asteroid Dimorphos. The collision changed Dimorphos's orbit successfully, and now scientists hope to study the space rock close-up to understand how to launch similar missions.

The ESA's Hera spacecraft will enter the orbit of Dimorphos (and its larger companion Didymos) in October 2026. By analysing the results of DART, Hera will offer information which could be used to repeat the feat with other objects.

"The impact was more dramatic than anybody anticipated," Whitehouse says. "At the moment, some preliminary gossip is that something similar to Dart would work, preferably two Darts. Now they're both launched on a Falcon 9 rocket: there are plenty of those around.

“We've already got the design of Dart. If we made another one or another two, perhaps made it a little bigger. That could be done relatively quickly.”

Gravity 'tug'

The concept of a (fictional) 'tractor beam' is a familiar one from science fiction such as Star Trek, in which a beam is used to hold spaceships in place and move them.

In reality, a ‘gravity tug’ would be a space probe that would travel alongside an asteroid, using its own gravity to subtly adjust the flight path of the asteroid.

Over time, the probe’s gravity would ‘move’ the asteroid onto a different path.

But this process would be time-consuming, and the problem is whether enough time remains with the asteroid designated 2024 YR4, Whitehouse explained.

"Gravity tractors probably won't work in this case, because we've not got enough time to do it. It’s also an untried technology," he added.