The asteroid 2017 YE5 was first discovered by scientists on December 21, 2017, after which scientists predicted its orbit, and eventually he approached Earth on June 21 and flew 3.7 million miles (about 5.95 million kilometers) from Earth, posing no obvious threat to Earth.
When it was closest to Earth, it was about 16 times the distance between Earth and Moon, and now, through analysis, scientists have pointed out that the asteroid is actually far more complex than scientists imagined, and observations have shown that it is not a rock but a "binary star" system surrounded by two objects that are more than 900 meters above each other.
NASA recently released detailed observational images analyzing this strange system that has just flown over Earth, revealing that two space rocks orbit each other and dance in flight. Experts say the two "couple" asteroids won't have a chance to collide with Earth, but they will return again, and the next time they'll be seen will be 170 years from now.
Astronomers also pointed out that because the two rocks of the asteroid are orbiting each other, it is easy to observe them from a certain angle and be mistaken for only one object, but after a long period of observation, the rotation between the two objects reveals a significant gap, and allows scientists to confirm that this is a "couple asteroid".
NASA says the two asteroids have some unique characteristics. For example, they are as black as charcoal compared to typical stony asteroids, which means they don't reflect as much light as possible. Scientists have made observations that the two asteroids may have different densities, compositions, or surface roughness, as significant differences can be seen in the reflectivity of the two objects.
Another special thing, of course, is that this system has unusual dimensions – it's actually rarer given the large size of these two objects. The researchers say the finding could help us understand these unusual systems and how they are formed. NASA also pointed out that similar "binary star systems" are relatively rare, and in the past 18 years, there have not been more than 50 other discovered "binary star systems".