https://www.cnet.com/news/earth-buzzing-asteroid-has-nasa-scientists-seeing-double/

Asteroid 2017 YE5 made the headlines when it slipped by Earth last month. Scientists estimated it to be taller than Burj Khalifa, the tallest skyscraper on our planet. On Thursday, NASA revealed something much more intriguing: asteroid 2017 YE5 is really two space objects orbiting each other.

Three different radio telescopes observed the asteroid as it came close to Earth. Scientists initially noticed what they thought were two lobes, but a closer look showed a gap between the distinct parts.