We Might Be Able to Nuke an Asteroid to Save the World After All, Study Says
by Jazz Shaw | The Debrief
It’s a subject that has enthralled fans of both science and science fiction for generations. An asteroid or comet is on a collision course with the Earth, threatening to wreak massive devastation and potentially wipe out humanity.
We received an unpleasant reminder of the non-fictional reality of this scenario recently when we learned that an asteroid named 2021 SG that was roughly one half the size of the Great Pyramid in Egypt had zipped past the Earth inside the orbit of the moon in September and NASA didn’t even see it until it was going by.
Is there a real-world solution to this terrifying possibility? Unfortunately, knowing about an incoming Near-Earth Object (NEO) in advance doesn’t do us much good unless we can actually do something about it. If you look to Deep Impact or Armageddon for solutions, you might be tempted to send a crew of space cowboys out into the void with some huge nuclear weapons to take care of the problem. But in the past, when such discussions have come up, scientists have assured us that nuking an asteroid wouldn’t work because you would simply risk generating multiple impact events from the wrecked asteroid.
That viewpoint appears to be changing, however. A recent study by a team of scientists that was published at Acta Astronautica indicates that under the right conditions, we could indeed use a nuclear blast to save the Earth from an incoming NEO. The report is titled “Late-time small body disruptions for planetary defense,” and as the name suggests, a significant “disruption” (meaning a nuclear blast) could produce a successful outcome for a modest-sized asteroid that was discovered too late to have its course significantly altered by other methods that have been previously discussed.
The Threat Is Real, but Probably Not Imminent
How real is the danger from a NEO and if we found one incoming, how would this nuclear disruptive intervention theory work? The Debrief reached out to Dr. Megan Bruck Syal, a physicist working in planetary science and planetary defense at Lawrence Livermore National Lab and one of the authors of the study. The first thing we wanted to determine is how many of these space rocks that are large enough to pose a serious threat to humanity are out there and what are the odds one of them might actually hit us.
“There are about 130,000 NEOs that are 100 m or larger,” Dr. Bruck Syal said, “and only approximately 20% have been discovered and had their orbits well-characterized. Each of these could wreak regional devastation. While more than 95% of asteroids 1 km or larger in diameter have been discovered and are known to not be an imminent threat to Earth, there are hundreds of thousands of possible city-flattening asteroids out there, and we have no idea if or when they may be a threat to Earth.”
“Something as small as 50 m, such as the Meteor Crater impactor, which was metallic, can take out a city,” she continued. “That crater is 1 km across and its impact released about 10 Megatons of TNT equivalent, which is roughly 1000 times more energy than the Hiroshima nuclear explosion.”