Avoiding Armageddon: How X-rays Could Save Earth From Asteroid Collision

Our planet is like a small island in the vast cosmos. The space is a hostile place. The ever-present danger of a huge asteroid colliding with our planet has long been a concern for scientists, space agencies and governments worldwide. While most asteroids that pass close to Earth are relatively harmless, a big one could potentially cause catastrophic damage, wiping out entire cities or even threatening humanity's existence. Along with NASA, other agencies and nations are taking the threat seriously and continue to work on different mechanisms to save Earth from an existential threat.

An idea romanticised in Hollywood movies is of a nuclear bomb detonation to destroy the incoming threat in space before it hits Earth. However, scientists have warned that blowing up an asteroid is not a viable solution-it could break into smaller fragments, which would rain down on Earth, causing even more destruction. Instead of using a nuclear explosion's power to gently push an asteroid off course without shattering it seems more plausible. Researchers at Sandia National Laboratories in Albuquerque, New Mexico, have been experimenting with the same technique. Scientists propose exploding the nuclear bomb at a distance, allowing the asteroid to be bathed in X-rays from the blast. These X-rays would transfer enough energy to the asteroid's surface to change its course, sending it in a different direction without breaking it apart.

Nathan Moore, a physicist at Sandia National Laboratories, explains that the key is applying the right amount of force to nudge the asteroid away from Earth. "The trick is to use just enough force to redirect the flying rock without splitting it into several equally deadly subsections advancing toward Earth," says Moore. This method is being seen as a potential game-changer in the field of planetary defence. Moore says, "A key fact was that asteroids in outer space aren't attached to anything. But in a lab, everything is pulled down by Earth's gravity, so everything is held in place by its gravitational attachment to something else. This wouldn't let our mock asteroid move with the freedom of one in outer space. And mechanical attachments would create friction that would perturb the mock asteroid's motion." While the idea might seem outlandish, the underlying physics is sound.

While nudging the massive asteroid by detonating a nuke in space offers a promising avenue, it is not the only solution under consideration. Other methods being explored include kinetic impactors, which involve ramming a spacecraft into the asteroid to alter its trajectory, and gravity tractors, which use the gravitational pull of a spacecraft to slowly deflect the asteroid. NASA's recent DART mission successfully crashed a spacecraft into an asteroid, proving that kinetic impact can alter an object's course. The idea is to just push the asteroid by a few inches and thereby altering its trajectory away from our planet.

While we may have the nuclear bombs and even spacecraft to carry them but identifying these planet-killer asteroids isn't so easy.

One of the biggest obstacles is the difficulty of detecting and tracking potentially dangerous asteroids. Many of these objects are small and dark, making them difficult to spot even with powerful telescopes.