Astronomers Just Found a Sneaky Asteroid Near the Sun—and It Highlights a Dangerous Blind Spot

Millions of asteroids are currently zipping through our solar system. These rocky remnants of the early solar system receive extra attention when their itinerary brings them too close to Earth—which, fortunately, astronomers can usually track in advance. But what happens if they can’t?

This could easily be the case for so-called “twilight” asteroids, whose position behind the glare of the Sun makes it tricky for astronomers to detect and track. If that wasn’t unsettling enough, the latest twilight asteroid—2025 SC79—is also the second-fastest asteroid ever identified, with an orbit of just 128 days around the Sun, according to a Carnegie Science release.

Hiding in plain sight?

Scott Sheppard, an astronomer with Carnegie Science, first observed 2025 SC79 with the Blanco 4-meter Telescope’s Dark Energy Camera in September. Follow-up observations by the Gemini and Magellan telescopes confirmed the sighting of the asteroid.

2025 SC79 is estimated to measure around 2,300 feet (700 meters) in diameter—almost twice the height of the Empire State Building. The asteroid’s size, as well as its fast orbit around the Sun, qualifies it as a “planet killer” asteroid, which Sheppard had been searching for.

A blind threat

“The most dangerous asteroids are the most difficult to detect,” Sheppard said in the release. Most asteroids enter telescopes’ detection range in the dark of night, he explained. Asteroids lurking near the Sun, on the other hand, are only visible at twilight.

This poses unique challenges for astronomers like Sheppard, who are on the lookout for potential threats. Given the importance of preemptive research for asteroid flybys, twilight asteroids could “pose serious impact hazards” if they approach Earth, Sheppard warned.

To be fair, there isn’t much we can do about the natural positioning of extraterrestrial objects. Still, Sheppard hopes that further screening of this twilight asteroid may uncover useful information about its composition and whether it could hold any clues for spotting similar objects in the future.

“Many of the Solar System’s asteroids inhabit one of two belts of space rocks, but perturbations can send objects careening into closer orbits where they can be more challenging to spot,” Sheppard said. “Understanding how they arrived at these locations can help us protect our planet and also help us learn more about Solar System history.”