Direct impact or nuclear weapons? How to save Earth from an asteroid

Direct impact or nuclear weapons? How to save Earth from an asteroid

Three techniques to avoid a castastrophic collision with an asteroid
Graphic showing three techniques being considered by scientists to avoid a castastrophic collision between Earth and an asteroid as NASA to crash the DART spacecraft into a mini-asteroid on Monday. Photo: Sophie RAMIS / AFP
Source: AFP

PAY ATTENTION: Сheck out news that is picked exactly for YOU ➡️ find “Recommended for you” block on the home page and enjoy!

NASA's DART mission to test deflecting an asteroid using "kinetic impact" with a spaceship is just one way to defend planet Earth from an approaching object -- and for now, the only method possible with current technology.

The operation is like playing billiards in space, using Newton's laws of motion to guide us.

If an asteroid threat to Earth were real, a mission might need to be launched a year or two in advance to take on a small asteroid, or decades ahead of projected impact for larger objects hundreds of kilometers in diameter that could prove catastrophic to the planet.

Or, a larger object might require hits with multiple spacecraft.

"This demonstration will start to add tools to our toolbox of methods that could be used in the future," said Lindley Johnson, NASA's planetary defense office, in a recent briefing.

Read also

Ukrainian geeks turned guerrillas make frontline drones

Other proposed ideas have included a futuristic-sounding "gravity tractor," or a mission to blow up the hypothetical object with a nuclear weapon -- the method preferred by Hollywood.

PAY ATTENTION: Enjoy reading our stories? Join YEN.com.gh's Telegram channel for more!

Gravity tractor

Should an approaching object be detected early -- years or decades before it would hit Earth -- a spaceship could be sent to fly alongside it for long enough to divert its path via using the ship's gravitational pull, creating a so-called gravity tractor.

This method "has the virtue that the method of moving the asteroid is totally well understood -- it's gravity and we know how gravity works," Tom Statler, a DART program scientist at NASA said at a briefing last November when DART launched.

The mass of the spacecraft however would be a limiting factor -- and gravity tractors would be less effective for asteroids more than 500 meters in diameter, which are the very ones that pose the greatest threat.

Read also

NASA to deflect asteroid in key test of planetary defense

In a 2017 paper, NASA engineers proposed a way to overcome this snag: by having the spacecraft scoop material from the asteroid to enhance its own mass, and thus, gravity.

But none of these concepts have been tried, and would need decades to build, launch and test.

Nuclear detonation

Another option: launching nuclear explosives to redirect or destroy an asteroid.

"This may be the only strategy that would be effective for the largest and most dangerous 'planet-killer' asteroids (more than one kilometer in diameter)," a NASA article on the subject says, adding such a strike might be useful as a "last resort" in case the other methods fail.

But these weapons are geopolitically controversial and technically banned from use in outer space.

Lori Glaze, NASA's planetary science division director said in a 2021 briefing that the agency believed the best way to deploy the weapons would be at a distance from an asteroid, in order to impart force on the object without blowing it into smaller pieces that could then multiply the threat to Earth.

Read also

Ford's electric drive reinvents historic Michigan factory

A 2018 paper published in the "Journal of Experimental and Theoretical Physics" by Russian scientists looked at the direct detonation scenario.

E. Yu. Aristova and colleagues built miniature asteroid models and blasted them with lasers. Their experiments showed that blowing up a 200-meter asteroid would require a bomb 200 times as powerful as the one that exploded over Hiroshima in 1945.

They also said it would be most effective to drill into the asteroid, bury the bomb, then blow it up -- just like in the movie Armageddon.

New feature: Сheck out news that is picked for YOU ➡️ find “Recommended for you” block on the home page and enjoy!

Source: AFP

Authors:
AFP avatar

AFP AFP text, photo, graphic, audio or video material shall not be published, broadcast, rewritten for broadcast or publication or redistributed directly or indirectly in any medium. AFP news material may not be stored in whole or in part in a computer or otherwise except for personal and non-commercial use. AFP will not be held liable for any delays, inaccuracies, errors or omissions in any AFP news material or in transmission or delivery of all or any part thereof or for any damages whatsoever. As a newswire service, AFP does not obtain releases from subjects, individuals, groups or entities contained in its photographs, videos, graphics or quoted in its texts. Further, no clearance is obtained from the owners of any trademarks or copyrighted materials whose marks and materials are included in AFP material. Therefore you will be solely responsible for obtaining any and all necessary releases from whatever individuals and/or entities necessary for any uses of AFP material.