Humanity has long been obsessed with its own demise. From Y2K to the end of the Mayan calendar, people have spent countless hours predicting cataclysmic futures. Thankfully, none of the fearmongering has manifested. But that hasn’t stopped Hollywood from fixating on horrific options for planet-wide destruction. Among the most famous tropes is a collision with a killer asteroid.
Forays into this theme have included 1958’s The Day the Sky Exploded, 1979’s Meteor, and 1998’s Armageddon. Fortunately, scientists at NASA now feel confident about their ability to deflect a killer asteroid, saving the planet. But there’s a catch…
Researchers will need years of prep work to pull off such a feat. Here’s everything you should know about how humanity can dodge the next cosmic bullet.
A Brief History of Asteroids and Earth
Although humans have long worried about a death-causing interplanetary collision, studying and recognizing the potential threat didn’t become legit until the 1980s. That’s when researchers officially linked dinosaurs’ extinction to a killer asteroid or comet. (For reference, a proper “planet-killing” rock measures at least 3,281 feet).
On the heels of this revelation, Australian-based engineer Michael Paine used a computer simulation to guesstimate how many dangerous asteroids have hit the Earth over the past 10,000 years. The results were alarming. Paine’s model pointed to more than 350 asteroids of significant size and destructive force pockmarking Earth. How big were these space rocks? Comparable to the asteroid that flattened 830 square miles of Siberian forest during 1908’s Tunguska explosion.
Tunguska took out 80 million trees, killed countless reindeer, and knocked people off their feet hundreds of miles away. It also resulted in broken windows and “a flash and bang” likened to artillery fire. Fortunately, the asteroid touched down in a sparsely populated part of Russia, translating to limited casualties. Nonetheless, the power of the event turned heads.
Deflecting Planet-Killing Projectiles
Today, scientists observe Asteroid Day on June 30th, Tunguska’s anniversary. This day remains a sober reminder that next time we might not get so lucky when it comes to the location of an asteroid impact. Does that mean it’s time to invest in an underground bunker designed to survive space rocks? According to NASA scientists, this approach might be overkill.
New science results confirm our #DARTMission‘s asteroid deflection technology can be an effective way to change the orbit of an asteroid, should there ever be a threat. The DART spacecraft intentionally slammed into asteroid Dimorphos in Sept. 2022: https://t.co/PdpCDG2zRn pic.twitter.com/79EPIXCaSW
— NASA (@NASA) March 1, 2023
Instead, researchers are working to deflect a potential planet assassin by crashing a spacecraft into it. And they recently used this tactic to successfully divert the orbit of a 525-foot-wide asteroid known as Dimorphos. A moonlet that orbits the larger asteroid Didymos, Dimorphos sits approximately seven million miles from the Blue Planet. In other words, Dimorphos doesn’t represent a threat to our existence. But due to its size and other characteristics, scientists declared it a fantastic target for testing space technology. The result? NASA’s project proved even more successful than initially hoped.
The rocket NASA used to reroute Dimorphos weighed 1,200 pounds and collided with the asteroid on September 26, 2022. Known as the Double Asteroid Redirection Test (DART), the object crashed into Dimorphos at 13,000 miles per hour, blasting over 1,000 tons of rock and dust off the asteroid. This trail of debris now stretches for thousands of miles and has resulted in Dimorphos’s re-classification as an “active asteroid” with a tail like a comet.
Dodging a Cosmic Bullet
Interestingly, the Hubble Telescope caught images of the dramatic impact, resulting in unprecedented images. As Jian-Yang Li of Arizona’s Planetary Science Institute explains, “We’ve never witnessed an object collide with an asteroid in a binary asteroid system before in real time, and … I think it’s fantastic.” That said, there’s a major caveat to all of this.
Intercepting and deflecting an asteroid the size of Dimorphos couldn’t happen in a day, a week, or even a month. Scientists would need several years, ideally decades, to make it happen. In other words, identifying earthbound asteroids years before they’re a threat is of the deepest concern. For context, about 3,000 near-Earth asteroids (NEAs) get discovered each year, adding to the current total of 28,000 NEAs.
This time-lapse from Hubble shows rapid changes to the asteroid Dimorphos after it was deliberately hit by the 1,200-pound NASA DART spacecraft in September. This impact was a test to see if asteroids could be deflected away from Earth: https://t.co/AQMocA4LZH pic.twitter.com/dGImD0YA8f
— Hubble Space Telescope (@HubbleTelescope) March 1, 2023
NASA’s Jet Propulsion Laboratory in SoCal hosts the Center for Near Earth Object Studies (CNEOS), which monitors these potentially hazardous objects. CNEOS plays a vital role in protecting the Earth from life-threatening asteroids through early detection. Coupled with DART, humans may stand a fighting chance against a space rock (unlike their dino predecessors). Jason Kalirai of Johns Hopkins Applied Physics Laboratory credits DART with offering “a bright future for planetary defense.”
The asteroid-nudging rocket has also paved the way for further research. Stay tuned for the 2024 launch of the Hera spacecraft, set to provide up-close views of Dimorphos’s post-DART scarred surface.
By Engrid Barnett, contributor for Ripleys.com