Back in December 2024, astronomers caught wind of something unusual—a small, fast-moving rock dubbed 2024 YR4 hurtling through space. Over the past several months, NASA’s eagle-eyed observations have tracked its path with increasing precision, revealing a roughly 1% chance that this cosmic wanderer could impact Earth in 2032. Now, before alarm bells start ringing, let’s break down what that really means and why there’s no need to panic.
In an ideal textbook scenario, you’d see neat, predictable ellipses drawn in black and white, with every gravitational tug neatly accounted for. But space isn’t a static chalkboard. Our solar system is a bustling gravitational ballet, where planets, moons, and even passing asteroids jostle each other, perturbing orbits in subtle—but crucial—ways. NASA’s models incorporate these messy realities, including Earth’s own gravitational cross section: a tiny, yet decisive, target. When an object like 2024 YR4 comes close enough, Earth’s gravity doesn’t just wave hello—it pulls the object in, and depending on the precise timing and location, it might just end up on a collision course.
Bear in mind the dot that represents the asteroid in the above simulation is a tiny TINY point compared to the planets.
Now, if this rock, roughly sized to deliver an 8-megaton punch, were to hit, it would pack an explosion that rivals the larger thermonuclear tests humanity has conducted. Sure, 8 megatons isn’t unprecedented on the scale of human-made bombs, but imagine that energy released over a densely populated area instead of a remote test site. And here’s the kicker: because both the asteroid’s path and Earth’s orbit carry uncertainties—and because our planet is rotating—the potential impact zone isn’t a pinpoint mark but rather a band of possibilities stretching from oceanic expanses to the outskirts of bustling cities in South America, Africa, India, or South China.
The impact date on Earth would be 22 December, 2032. This is where we've calculated the asteroid could hit (credit Daniel Bamberger/Wiki Commons).A lot of the risk is over water, but quite a few populated areas too in South America, Africa, and Asia. (4/x)
— Jonathan O'Callaghan (@astrojonny.bsky.social) February 4, 2025 at 5:53 AM
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YR4 was discovered on 27 December. Its impact risk was raised in July to level 3 on the Torino scale, one of the highest ever.For an asteroid this size, 40-100m wide (the length of a football field), the highest it can reach is level 8 – 100% chance of impact. (2/x)
— Jonathan O'Callaghan (@astrojonny.bsky.social) February 4, 2025 at 5:53 AM
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But here’s the good news: we have options.
One method involves attaching rockets to the asteroid—a gentle nudge to shift its trajectory. Unfortunately, 2024 YR4 spins so rapidly that securing a steady push isn’t as straightforward as it sounds. An alternative, more elegant solution is the gravitational tractor. Picture a satellite entering a calculated orbit around the asteroid, using its own gravity (and tiny, continuous thrust from onboard engines) to slowly tug the asteroid onto a safer course. The beauty of this method is its reliance on patience; the sooner we start, the more time that modest force has to add up into a big change.
If both these approaches were to falter? Then, as dramatic as it sounds, we could consider a controlled series of nuclear explosions near the asteroid. It’s important to stress that “blowing it up” isn’t what’s envisioned—space is a vacuum, so there’s no explosive shockwave like on Earth. Instead, carefully calibrated detonations would impart momentum, shifting the asteroid’s course. Hollywood might love the spectacle, but in reality, it’s a last-resort strategy reserved for when every other option has been exhausted.
Bottom line
With a mere 1% impact probability projected for 2032, we have more than enough time to develop and deploy any of these deflection strategies. Even in the worst-case scenario, if an impact appears imminent, we can mitigate the damage by evacuating regions within the predicted impact corridor. The real challenge isn’t the rock in space—it’s our collective human nature. Will the global community rise above parochial interests and come together to protect vulnerable regions? Or will we shrug it off because the potential disaster isn’t in our backyard?
For now, rest assured that NASA, along with the global scientific community, is on the case. Our arsenal of deflection methods—from rocket nudges to gravity tractors, and yes, even nuclear options—ensures that we’re not sitting ducks waiting for cosmic bad luck.
References
- NASA Planetary Defense Coordination Office. “About the PDCO.” NASA. https://www.nasa.gov/planetarydefense
- JPL Center for Near Earth Object Studies (CNEOS). “NEO Database.” NASA Jet Propulsion Laboratory. https://cneos.jpl.nasa.gov/
Mass-Optimized Gravity Tractor for Asteroid Deflection https://ui.adsabs.harvard.edu/link_gateway/2022JGCD...45.2318K/doi:10.2514/1.G006574
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