Just in time for the autumn theme of ghouls and ghosts, an asteroid with an appearance akin to a human skull is once more turning its eerie gaze toward Earth.
Nicknamed the "Halloween asteroid," but officially recognized as 2015 TB145, the 2000 foot-wide rock was first discovered in early October 2015. During its closest approach on Oct. 30-31 of that year at a sweat-inducing distance of only 302,000 miles, the asteroid's spooky appearance was captured by a trio of giant, Earth-based radio telescopes.
The Green Bank Telescope in West Virginia captured the asteroid in the early morning hours of Halloween 2015 during a different period in its rotation. As shown below, the images offer a side-perspective of what looks more akin to an angry face.
While the surprise 2015 flyby was the closest this creepy visitor has come to Earth in at least 500 years, its 2018 approach on Nov. 11 will comfortably keep it 24 million miles from Earth. Looking ahead in our lifetimes, its next closest visit will occur on Nov. 1, 2088, at a distance of just over 5 million miles. (So prognosticators of doom may be better off hitching their carts to one of the many more Earth-threatening asteroids.)
Ghostly remains of a comet
Researchers studying the orbit of 2015 TB145 now believe the object is likely all that remains of long-dead comet. Numerous passes around the sun likely stripped the comet of its volatiles.
"We found that the object reflects about 6 percent of the light it receives from the sun," said Vishnu Reddy, a research scientist at the Planetary Science Institute in Tucson, Arizona, said in a press release. "That is similar to fresh asphalt, and while here on Earth we think that is pretty dark, it is brighter than a typical comet which reflects only 3 to 5 percent of the light. That suggests it could be cometary in origin — but as there is no coma evident, the conclusion is it is a dead comet."
RIP Halloween asteroid — but please, no future trick or treats on Earth's doorstep.