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Asteroids have always been part of Earth's story. From the early chaotic days of the solar system to the asteroid that wiped out the dinosaurs 66 million years ago, these space rocks have shaped our planet’s history. But what if another large asteroid were headed our way? Thankfully, NASA and its Planetary Defense Coordination Office (PDCO) are working hard to protect Earth from potential impacts.

Why Do Asteroids Hit Earth?

Asteroids are leftover "building blocks" from the formation of the solar system. They orbit the Sun, but their paths can be altered by gravitational forces from planets, other asteroids, or even sunlight. Over time, some asteroids end up on collision courses with Earth. While most are small and burn up in the atmosphere, larger ones pose a serious threat.

How NASA Tracks Potential Threats

The Planetary Defense Coordination Office (PDCO), established in 2016, tracks and monitors near-Earth objects (NEOs). These are asteroids and comets that come within 0.05 AU (about 5 million miles) of Earth. NASA uses telescopes like NEOWISE and ground-based observatories to find and study these objects.

As of now, more than 36,000 NEOs have been discovered, and NASA estimates there are still thousands more to find. Fortunately, none of the currently known NEOs pose a significant threat within the next 100 years.

What Happens if We Find a Dangerous Asteroid?

If an asteroid were on a collision course with Earth, scientists have several strategies to prevent disaster:

• Gravity Tractor: A spacecraft could "park" near an asteroid and use its gravity to slowly pull the asteroid into a safer orbit.
• Kinetic Impact: This involves crashing a spacecraft into the asteroid to nudge it off its collision course. NASA’s DART mission successfully tested this method.
• Nuclear Deflection: In extreme cases, a nuclear explosion near the asteroid could create enough force to change its trajectory.

NASA's DART Mission: A Success Story

In 2021, NASA launched the Double Asteroid Redirection Test (DART), a groundbreaking mission to test our ability to deflect asteroids. The spacecraft traveled millions of miles to crash into Dimorphos, a small asteroid orbiting a larger one called Didymos. The impact shortened Dimorphos's orbit by 33 minutes, proving that we can alter an asteroid's path if needed.

What’s Next in Planetary Defense?

NASA is now working on a new telescope called NEO Surveyor, set to launch in 2027. This advanced observatory will help detect even more potential threats and provide earlier warnings. With continued advancements, humanity is becoming better equipped to prevent a catastrophic asteroid impact.

While we can't eliminate the risk entirely, the efforts of NASA and its partners give us confidence that we can protect our planet from cosmic dangers.