By Jonny Lupsha, Wondrium Staff Writer
A near-Earth asteroid won’t strike for at least another 100 years. Earlier predictions claimed an impact was due in 2029, 2036, and 2068, but NASA now says we have more time left. However, we do have observational and defensive measures in mind.
If nothing else, an 1,110-foot asteroid is one thing to scratch off humanity’s list of worries for the foreseeable future. Apophis is an asteroid discovered in 2004 that, if it struck Earth, could kill 10 million people. Its flight path in recent years has led many to conclude that it will impact Earth at various times in the next 50 years, but now scientists see that as nearly impossible.
Near-Earth asteroids are one of the more frightening natural phenomena that could cause mass casualties, due in part to their scale and the implications surrounding them—as any dinosaur will tell you.
In her video series A Field Guide to the Planets, Dr. Sabine Stanley, a Bloomberg Distinguished Professor in the Morton K. Blaustein Department of Earth and Planetary Sciences at Johns Hopkins University, said near-Earth asteroids have to meet several qualifications.
Keeping an Eye on the Sky
The idea that an enormous asteroid could come out of nowhere and end life on Earth is terrifying. However, it’s a lot less terrifying now than just 40 years ago.
“The good news is that we now know much more about what’s out there,” Dr. Stanley said. “In 1980, only about 50 near-Earth asteroids were known; that number slowly increased to 500 by 1998, which was the year that Hollywood released not one, but two blockbuster movies about asteroids—Deep Impact and then Armageddon.
“Within just two years, the number of known near-Earth objects suddenly doubled to 1,000 by the year 2000, and the numbers increased quickly thereafter, to around 20,000 by 2019.”
Dr. Stanley said that out of those, only about 1,000 are larger than one kilometer, and global efforts continue in the search for more. By knowing that these objects are there, and in which direction they’re traveling, we can keep an eye on those that could spell trouble for us.
The Best Offense…
Scientists will sometimes use a scale called the Torino scale to qualify the dangers of individual near-Earth asteroids. It combines the size or energy of an asteroid with the probability of it hitting Earth and is then assigned a number. The asteroid that killed the dinosaurs is ranked a 10, while the Tunguska event in Siberia—which leveled 2,000 square kilometers of forest—is an 8. No currently monitored object has ever rated above a 4, which means a 1% chance of impact.
“Now let’s suppose, hypothetically, we did find an asteroid—let’s say a large asteroid, Torino scale 10—on a collision course with Earth,” Dr. Stanley said. “What could we do? The movie Armageddon suggests using nuclear bombs to break it into pieces and change the trajectories of the pieces.”
Would an idea like that actually work? According to Dr. Stanley, NASA is really considering it. She said that in 2022, the Double Asteroid Redirection Test (or DART) will intentionally impact the small moon of the asteroid Didymos. Its moon is about 160 meters in diameter and doesn’t even have a proper name, but the DART mission will test our ability to redirect an asteroid of that size.