Nuclear Blast Might Safeguard Earth from Incoming Asteroid Threat

Fortunately, the Earth is not under threat from a huge asteroid that would cause irreversible damage, as was the case during the extinction of the dinosaurs 66 million years ago. Nevertheless, experts are thinking of solutions to deal with any eventuality, and among the avenues being considered, there is that of causing a… nuclear explosion!

It might sound like a Hollywood script, but researchers at a U.S. government center have been digging into the idea, even conducting the first full demonstration of nuclear-assisted planetary defense.

Anticipate to protect

“For most people, the danger posed by asteroids seems remote,” says Professor Nathan Moore. “But our planet is hit every day by small asteroids. We call them shooting stars. We don’t want to wait for a big asteroid to appear and then scramble to find the right way to deflect it.”

Physicists at Sandia National Laboratories have recorded with nanosecond precision how a huge pulse of radiation triggered by a nuclear explosion could vaporize the flank of a nearby asteroid to prevent it from hitting the ground.

“We use so-called X-ray scissors to place surrogate asteroidal material into free space, simultaneously shearing the carriers and vaporizing the target surface,” they explain in their report. “The ensuing explosion accelerates the dummy asteroidal material into a full-scale asteroid intercept mission.”

Deflect the asteroid by the blast of the explosion

Of course, they didn't do their simulation in the open air, but in a vacuum chamber with their “Z machine,” a pulsed energy device considered the most powerful in the world. They exposed fake asteroid pieces to intense X-ray pulses, similar to those emitted during nuclear explosions. These fake asteroids were subjected to gravity as soon as the supports were destroyed, and they fell less than 2 millionths of a millimeter before the end of the 20-microsecond experiment.

The blast is so violent that it heats the surface to tens of thousands of degrees, producing a rapidly expanding ball of gas capable of knocking the asteroid off course. In this case, the fake asteroid pieces were propelled at nearly 60 mph.

For asteroids several kilometers wide

“The vaporized material is thrown to one side, pushing the asteroid in the opposite direction,” Dr. Nathan Moore explained in Nature Physics. “It’s as if the asteroid is turning into its own rocket.”

The only unknown, but apparently easy to solve, is the precise calculation of where to detonate this “bomb”. However, nothing says that it would be enough to deflect an asteroid like Chicxulub that hit the Earth at the time of the dinosaurs. Its width is estimated at 10 kilometers!

A priori, this type of solution would be suitable for asteroids measuring up to 4 km wide. “If the warning time is sufficient, we can certainly deflect larger asteroids,” Moore tempers without giving a maximum size.

The only solution?

Asked by The Guardian about this experiment, Professor Gareth Collins, a planetary scientist at Imperial College, acknowledged that it might be the only possible one. “I still have a strong preference for non-nuclear options, particularly single or multiple kinetic impactors, because we know they are technologically feasible,” he said. “But for a very large asteroid or a short warning time, this type of approach might be our only option.”