Animated GIF with resolution of 25 feet (7.5 meters) per pixel. Image: NAIC-Arecibo/NSF
On Halloween, Earth received its very own cosmic trick-or-treater when asteroid 2015 TB145 zipped by at only 1.3 times the distance between Earth and the Moon (486,000 km). It seems that the 2,000-foot-wide asteroid, which was discovered just a few weeks back, decided to honor the holiday by dressing up as a spooky space skull.It gets better: The asteroid may have a backstory to match its ghoulish appearance. Scientists studying the object noted that it was traveling at the breakneck speed of 126,000 km per hour, which is unusually fast for an asteroid. On top of that, they noted that the object's surface was surprisingly bright, suggesting that the asteroid might be the dead husk of a comet."We found that the object reflects about six percent of the light it receives from the Sun," said Vishnu Reddy, a research scientist at the Planetary Science Institute, Tucson, Arizona, in a statement."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 three to five percent of the light," he continued. "That suggests it could be cometary in origin—but as there is no coma evident, the conclusion is it is a dead comet."So to sum up, a skull-shaped cometary corpse visited Earth's doorstep just in time for Halloween. Add to that the genuinely frightening fact that we had no idea this large body even existed until October 10, and you get a whole bundle of seasonally appropriate chills. Ghosts, witches, and vampires have nothing on asteroid 2015 TB145.