Scientists at Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia have discovered a pair of similarly-sized asteroids locked in their binary orbit around a mutual center of gravity.
The team first detected the odd object, known as 2017 YE5, in December of last year. At the time, it sat an such an angle that scientists could not determine if it was two distinct objects or two lobes of the same object joined at one point, Science Alert reports.
However, last month the pair came closer to Earth than they had ever been, which then allowed astronomers to get a much better look. They did that by shooting a radar signal out towards the asteroid. The beam then bounced off the object and shot back down towards our planet. Individual observations were made as well.
That revealed the asteroids make one full orbit around each other once every 20 to 24 hours.
Though observations estimate that about 15 percent of all near-Earth asteroids that measure more than larger than 650 feet across are binaries, most of them are made up of one large asteroid and one small one.
YE5 is unique because both objects measure 3,000 feet across, showing that they are roughly the same size. In addition, the rocks each reflected the radar signal differently. That shows they likely have different surface roughness or density.
More research needs to be done on the pair before such questions can be answered, and the team plans to do that the next time the asteroids fly past Earth in roughly four-and-a-half years.
In the meantime, researchers will analyze data taken from recent observations and attempt to discover more about the densities of the object. That could then provide new insight into its structure and composition.