The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS I) on Haleakala located the largest asteroid to pass close to the earth in nearly a decade.
The asteroid called 2015 TB145 was discovered on Oct. 10, 2015.
While Slooh has nicknamed the asteroid “Spooky,” it’s more that it is passing closest to Earth on Halloween and was located such a short time ago.
“We can say with a very good deal of certainty that no asteroid or comet large enough to threaten life as we know it will hit Earth in the next 100 years,” said Donald Yeomans in 2013. Yeomans is a senior research scientist and manager of the Near-Earth Object Program Office at NASA’s Jet Propulsion Laboratory.
The object will approach the Earth about 0.00326 au (1.3 lunar distances or about 310,000 miles) on Halloween morning at about 7:12 a.m.
NASA estimates that the asteroid has a diameter between 918 to 2,034 feet. The encounter velocity of 2015 TB145 is about 78,293 miles per hour (35 km/s), which is unusually high according to NASA.
2015 TB145 will be the closest approach by an object this large until 1999 AN10 approaches within 1 lunar distance in August 2027. The last approach closer than this by an object this size was by 2004 XP14 in July 2006 at 1.1 lunar distances.
For people looking to see 2015 TB145, it could reach 10th magnitude before sunrise on October 31 for observers in North America, but it will be close to the waning gibbous Moon and probably challenging to see with small telescopes. The asteroid will be in Taurus at the time of closest approach. After that, 2015 TB145 will be a daytime object and too close to the Sun to observe with optical telescopes.