With these technologies, Earth might be able to dodge any cosmic curveballs thrown our way.
Have you ever wondered what could happen if Earth was under an asteroid attack? Movies often depict these events as catastrophic events causing massive devastation. Imagine an asteroid the size of a house striking Earth at 30,000 miles per hour—its impact could rival the atomic bomb dropped on Hiroshima. After such an impact, our planet would be shrouded in dust, severely blocking sunlight and leading to a catastrophic scenario for all living things. For perspective, the last asteroid attack of such magnitude wiped out an entire species of dinosaurs millions of years ago.
Today, asteroids continue to be a source of concern for scientists. NASA has identified an asteroid, named Apophis after the Egyptian God of Chaos, which was predicted to come alarmingly close to Earth on April 13, 2029. Skimming by at about 20,000 miles from our planet, Apophis is no small pebble—it’s larger than India’s biggest cricket arena, the Narendra Modi Stadium, measuring between 340 and 450 meters in diameter. Space scientists warn that any asteroid over 300 meters across has the potential to unleash catastrophic damage on a continental scale or even trigger mass extinctions.
But there’s hope—thanks to cutting-edge space technology. Here’s how we’re preparing to counter these celestial threats.
1. Kinetic impactor
One promising defense strategy against asteroid threats is the “kinetic impactor”. This method sends a spacecraft or rocket to collide with an incoming asteroid. By striking the asteroid at just the right angle and speed, we can nudge it off a collision course with Earth. The impact not only pushes the asteroid but also generates ejecta—material blasted off the asteroid’s surface—which adds additional thrust through recoil effects.
A prime example is NASA’s Double Asteroid Redirection Test (DART). On November 23, 2021, a SpaceX Falcon 9 rocket was launched from California’s Vandenberg Space Force Base, to test out the kinetic impactor method Dimorphos——a small, non-threatening asteroid perfect for a test run. The spacecraft made contact with Dimorphos in September 2022, striking it at a blistering speed of 14,000 miles per hour. This successful test not only proved the concept but also marked a significant milestone in our planetary defense efforts.
2. Gravity tractors
The gravity tractor is a proposed method that involves a spacecraft using its gravitational pull to subtly change the course of an asteroid. This method doesn’t involve direct contact with the asteroid. Instead, the spacecraft hovers nearby, slowly pulling the asteroid off its collision path with Earth through steady gravitational attraction. This technique is incredibly precise and avoids kicking up dust clouds that could obscure the operation.
The key to success with gravity tractors is time. The earlier we detect an asteroid—ideally, a decade or more before it’s on track to hit us—the better. This allows for small, incremental adjustments to its path, ensuring a smooth diversion from Earth. Unlike the more abrupt kinetic impactor method, which might break an asteroid into several dangerous pieces, gravity tractors keep the space rock whole, reducing the risk of creating additional hazards.
However, there are limitations to this method. The larger the asteroid (think over 500 meters in diameter), the less effective a gravity tractor becomes due to the massive size of these celestial bodies compared to the spacecraft. Also, this method requires a good deal of advance notice. If we find out about an asteroid’s deadly path too late, we might have to turn to quicker, more forceful options.
3. Nuclear explosions
In scenarios where time is tight and other methods might not cut it, a nuclear explosion could be our emergency brake. By detonating a nuclear device near an asteroid, we harness a powerful burst of X-rays and shock waves to push the asteroid off its deadly path. The explosion vaporizes part of the asteroid’s surface, creating a massive gas bubble that expands rapidly and exerts enough force to change the asteroid’s trajectory—this is Newton’s third law in action: for every action, there’s an equal and opposite reaction.
Sandia National Laboratories has recently demonstrated the viability of this technique. Their researchers simulated nuclear blasts using a potent X-ray generator on materials that mimic those of asteroids. Their experiments suggest that we could potentially deflect asteroids up to four kilometers across if we act from a safe distance.
This approach is particularly useful when we’re caught off guard by an asteroid with little lead time—less than a year, for example. The sheer energy from a nuclear blast can change the trajectory of even the largest space rocks, which might be too big for other deflection methods to handle.
However, it’s not without its drawbacks. Blowing up an asteroid could create a cloud of space debris, posing risks to other satellites or even Earth itself. That’s why using nuclear explosions is considered a last resort, reserved for those nail-biting moments when late discoveries leave us with few options.
Expert opinion: How much should we worry about Apophis?
Since its discovery in 2004, the predictions about whether the asteroid Apophis will collide with Earth have seen significant revisions, thanks to continuous monitoring and new research. Initially, Apophis was expected to pass dangerously close to Earth in 2029, with subsequent estimates looking at 2036 and then 2068.
However, recent advanced radar observations have allowed NASA to refine Apophis’s orbit around the Sun considerably. Davide Farnocchia from NASA’s Center for Near-Earth Object Studies reassures us, stating, “A 2068 impact is no longer a possibility, and our calculations show no impact risk for at least the next 100 years.” Consequently, NASA has removed Apophis from the Sentry Impact Risk Table, a list that tracks celestial bodies posing significant risks to Earth.
Despite NASA’s confidence, some experts are still cautious. They warn that Apophis will skim by Earth in 2029 at less than one-tenth the distance to the Moon—a proximity close enough to pose a risk to some of our satellites. Moreover, there’s a wild card: Apophis could potentially collide with another asteroid in the next five years, altering its trajectory significantly.
Paul Wiegert, a solar system dynamics expert at Western University in Canada, explored this unlikely but possible scenario in a recent study published in The Planetary Science Journal. His findings suggest that while the chances are slim, we can’t entirely rule it out. We’ll need to keep an eye on Apophis and reassess its threat level in 2027 when it comes back into view.
In the meantime, space agencies are not just waiting around. NASA is gearing up to send the OSIRIS-APEX mission to closely study Apophis on April 23, 2029, at a distance of about 2,500 miles. This mission aims to analyze the asteroid’s chemical composition, map its surface and snap detailed images. Similarly, ISRO has stepped up with its Network for Space Objects Tracking and Analysis (NETRA), ready to monitor Apophis and other potential threats from space. This system is crucial for spotting space debris and other hazardous materials.
With the vastness of space and its many uncertainties, even a seemingly harmless asteroid could become a serious threat. But thanks to advancements in space technology, including asteroid deflectors and gravity tractors, we’re better prepared than ever to handle whatever comes our way. Remember, being prepared is always better than being caught off guard!
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- Startups That Are Cleaning the Space
Header Image from Freepik
