The phrase “space rock” appears insufficient to describe what NASA has recently detected. Usually, a rock is something you might toss to attract attention or utilize to secure a picnic blanket. Nonetheless, this particular rock measures 660 feet across, covering more than two American football fields. The asteroid, designated 1997 QK1, reached its nearest point to Earth on August 20, at a distance of 1.9 million miles. This ancient fragment hasn’t been this close to our planet in over 350 years.
The flyby enabled astronomers to investigate its size, rotation, surface, and form. Prior to obtaining these images using the Deep Space Network’s Goldstone Solar System Radar, scientists had limited knowledge about it. Now, it’s less enigmatic. As per NASA, the asteroid is deemed potentially hazardous, but it does not present any risk to Earth in the foreseeable future.
Countless asteroids revolve around the sun, leftovers from the solar system’s creation 4.6 billion years ago. Most are benign, located in the belt between Mars and Jupiter. Occasionally, gravity nudges one nearer to Earth. At present, none are on a collision trajectory with us. Nonetheless, astronomers are keeping track of nearly 40,000 large space rocks and suspect thousands more are out there. Telescopes identify hundreds of new ones each year.
“An asteroid impact is an exceptionally rare occurrence,” remarked Lindley Johnson, NASA’s former planetary defense officer, in 2022. “Perhaps once every hundred years is there an asteroid that would truly concern us and we would aim to deflect.”
Despite the slim odds of one heading toward Earth, such impacts can be devastating. NASA posits that a 100 to 170-foot-wide asteroid could obliterate a small city. In 2013, a 60-foot meteor detonated over Chelyabinsk, Russia, damaging structures and injuring 1,600 individuals.
To avert such situations, nations are creating warning systems and deflection strategies. NASA showcased the practicality of these initiatives in 2022 when its $330 million DART mission collided with an innocuous asteroid, modifying its path. The mission achieved considerable success, although subsequent studies have shown the outcomes are more intricate than expected.
The comprehensive radar images of 1997 QK1 provide scientists with essential insights into the dynamics of such asteroids, which is vital for crafting planetary defense tactics, irrespective of the threat level. Through a sequence of 28 images, astronomers learned that the asteroid completes a full rotation every five hours and is a “contact binary” with a peanut shape, characterized by its two rounded lobes. One lobe is twice the size of the other, and both feature valleys “tens of meters deep.”
Around 15 percent of near-Earth asteroids of similar size or larger exhibit this shape since many are not singular solid rocks but rather loose aggregates of debris that consolidate over time. The asteroid is expected to come closer to Earth in 2039, arriving within 1.5 million miles, roughly six times the distance to the moon.