Artist’s concept of what binary asteroid 2017 YE5 might look like. The two objects showed striking differences in radar reflectivity, which could indicate that they have different surface properties. Image credit: NASA/JPL-Caltech
New observations by three of the world’s largest radio telescopes have revealed that an asteroid discovered last year is actually two objects, each about 900 metres (3,000 feet) in size, orbiting each other.
Near-Earth asteroid 2017 YE5 was discovered with observations provided by the Morocco Oukaimeden Sky Survey on 21 December 2017, but no details about the asteroid’s physical properties were known until the end of June. This is only the fourth “equal mass” binary near-Earth asteroid ever detected, consisting of two objects nearly identical in size, orbiting each other. The new observations provide the most detailed images ever obtained of this type of binary asteroid.
On 21 June 2018, the asteroid 2017 YE5 made its closest approach to Earth for at least the next 170 years, coming to within 6 million kilometres (3.7 million miles) of Earth, or about 16 times the distance between Earth and the Moon. On 21 and 22 June, observations by NASA’s Goldstone Solar System Radar (GSSR) in California, United States, showed the ...