Artist's rendering of asteroids and space dust
Artist's rendering of asteroids and space dust NASA/JPL-Caltech

Cosmochemist Natalie Starkey warned that NASA's plan to destroy a planet-killer asteroid could drastically backfire. The scientist said that blowing up an approaching asteroid could be very dangerous for Earth.

In terms of planetary defense, NASA has a number of systems in place to protect Earth from a massive asteroid collision. One of these includes the use of a kinetic impactor. According to NASA, this method involves attaching a kinetic impactor device on the tip of a nuclear weapon.

As the weapon approaches an incoming asteroid, the kinetic impactor will detonate on its surface to create a deep crater. The nuclear weapon will then explode inside the crater. Theoretically, the subsurface explosion caused by the nuclear device will send shockwaves within the asteroid, causing it to break apart completely.

For Starkey, whose area of expertise is a combination of space science and geochemistry, a kinetic impactor may not always be a hundred percent effective. For one, NASA should consider the overall composition of the asteroid and how it would react to a subsurface blast.

"NASA suggests that a simple kinetic impactor is 'the most mature approach' to deflecting a [near-Earth object], as long as it consists of a small, single body," Starkey said according to Express. "However, if we were to intentionally, or accidentally smash the object during this process, then the outcome for Earth could be harder to predict."

Ideally, the series of explosions from the kinetic impactor and nuclear device should be enough to break up a massive asteroid into tiny fragments. These should be small enough to harmlessly burn up in Earth's atmosphere.

However, there's also a chance that the explosions will cause the asteroid to break up into large chunks of cosmic debris. The original momentum of the asteroid, as well as the force caused by the explosions, could propel these large chunks towards Earth.

If this happens, different areas of the planet will experience multiple impact events. Although these impact events will not be as powerful as the one that would have been caused by a whole asteroid, they will still cause significant damage to populated areas such as cities and towns.

"Depending on the composition of the space object, it might fragment into tiny dust-sized pieces that could rain down on Earth, or it might break into just a few large pieces, which if heading for Earth impact, could make matters worse," Starkey said.