Potentially hazardous asteroid to safely pass Earth Monday
Potentially hazardous asteroid to safely pass Earth Monday
Back on October 24, 2005, the Catalina Sky Survey on Mount Lemmon in Arizona discovered a near-Earth asteroid that might be nearly a mile wide. Because the asteroid – named 2005 UK1 – can come within 19.5 lunar distances of Earth and is larger than 140 meters, it earns the designation of potentially hazardous asteroid. On January 12, 2026, asteroid 2005 UK1 will come within .08 astronomical units (AU, or sun-Earth distance) of Earth. This is a safe distance and not even within the 19.5 lunar distances figure. In fact, as it passes Earth on Monday, it will be 32 times farther than the distance to the moon. So there is no need to worry!
How big is the asteroid?
So exactly how big is this asteroid? Astronomers determine the size of near-Earth asteroids based on their brightness, or magnitude. The brighter it is, the larger the object is likely to be. Asteroid 2004 UK1 has a magnitude of 18.1. That’s well beyond what you can see in an average backyard telescope. But it’s bright enough that it means 2005 UK1 is somewhere between 0.4 and 0.85 miles wide (0.6 and 1.4 km). It’s about 97% larger than most known near-Earth objects.
How does that compare to other asteroids? Well, 2005 UK1 is an Apollo asteroid. That means its orbit intersects with Earth’s orbit. But it’s not the largest-known Apollo asteroid. That distinction goes to 1866 Sisyphus, which has a diameter of about 5 miles (8.5 km) across.
Another large Apollo asteroid is 3200 Phaethon, the parent object of the Geminid meteor shower. It spans about 3.6 miles (5.8 km). But – if 2005 UK1 falls at the larger range of its estimate – it’s still large enough to be considered a planet killer. That nickname is for any asteroid larger than 1 kilometer. But again, while asteroid 2005 UK1 is passing close to Earth in the grand scheme of our solar system, it is not passing close enough to affect Earth in any way.
How does it compare to asteroids that have hit Earth? The Chelyabinsk meteor that exploded in the air over Russia in 2013 was about 65 feet (20 meters) wide. And the Tunguska asteroid that also exploded above Russia, in 1908, was somewhere around 160 to 330 feet (50 to 100 meters) in size.
When will 2005 UK1 be closest to Earth?
On Monday, the asteroid will make its closest pass by Earth at 10:26 UTC. That translates to 4:26 a.m. CST. But again, it will be more than 32 lunar distances from Earth at that time. The last close encounter Earth had with 2005 UK1 was on April 24, 2018. And the next one will be on December 24, 2029. But both of those encounters are at a greater distance than the pass on January 12, 2026.
Bottom line: A potentially hazardous asteroid, 2005 UK1, will safely pass Earth on January 12, 2026. At this time it will be more than 32 times the moon’s distance away.
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