LONDON: Remember the asteroid that zoomed past Earth last weekend? New high-resolution images of it have revealed a world of mysterious pits and other complex features.
The 500-metre-wide Halloween asteroid – 2015 TB145 – was discovered only a few days before it flew about 480,000 kilometres above the Earth, which is relatively close in cosmic terms.
Astronomers saw the flyby as a great opportunity to study the ancient space rock which, fittingly, bore an eerie resemblance to a skull.
The new images revealed a world of pits, pronounced concavities, bright spots that might be boulders, and other complex features that could be ridges.
The radar images have a spatial resolution of four metres per pixel, and were obtained by sending microwaves from NASA’s Jet Propulsion Laboratory Deep Space Communications Complex 70-metre antenna at Goldstone, California, toward the asteroid.
This signal bounced off the asteroid which was crossing near the constellation Ursa Major at the time, and its radar echoes were received by the 100-metre Green Bank Radio Telescope in West Virginia.
The first radar images of 2015 TB145 were generated by the giant 305-metre Arecibo Radio Telescope in Puerto Rico a week earlier, and confirmed it is spherical in shape and completes a rotation about once every five hours.
Asteroid 2015 TB145 returns to Earth’s neighbourhood in September 2018, when it undertakes a more distant swing past at a more comfortable 38 million kilometres, or about a quarter the distance between the Earth and Sun.
