The spooky, skull-like asteroid 2015 TB145 that flew by Earth on Halloween is no longer a mystery. Scientists spent the weekend bombarding the asteroid to receive detailed radar images of the 2,000-foot-diameter object. NASA on Tuesday released new images of the Halloween asteroid that reveal its general shape, size and a few interesting surface features.
The radar images were created by sending microwaves from the DDS-14 antenna at Goldstone, California to the asteroid. These waves "ping" the object and get sent back to Earth where they were picked up by National Radio Astronomy Observatory's Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.
— Arecibo Radar (@AreciboRadar) November 2, 2015
Previous radar images collected by the Arecibo Observatory resembled a skull and provided preliminary estimates of the object's shape and size. The first radar images revealed asteroid 2015 TB145 to be larger than expected. "The bright and dark features are an indication of surface irregularities. For example, the central dark feature may be a large circular depression, possibly an impact crater," James Richardson, Universities Space Research Association scientist in the Planetary Radar Group, said in a Facebook post Friday.
The new images were collected by the Green Bank Telescope Saturday when the asteroid was around 300,000 miles from Earth. The radar images highlight several depressions in the asteroid along with possible ridges and boulders. The differences may be due to the Green Bank Telescope observing the asteroid during a different part of its rotational period, Lance Benner, head of NASA's asteroid research program, said in a statement.
The Halloween asteroid flyby posed no threat to Earth, but it was a boon for scientists. The next time asteroid 2015 TB145 passes Earth, in September 2018, will be at a very comfortable distance of 24 million miles.