This is our best look yet at asteroid 2014 JO25, which made its closest pass by Earth for at least the next 500 years on April 19, 2017. The animation above is composed of radar observations made from NASA’s Goldstone facility in California when the asteroid was between 1.53 and 1.61 million miles away. These and earlier, lower-resolution images obtained the previous day (you can see those here) showed this asteroid to be a contact binary—two objects connected by a “neck” of material, not unlike the comet 67P that ESA’s Rosetta mission explored. The largest section of JO25 is estimated to be 2,000 feet (610 meters) wide, and at its widest the entire asteroid is about 3,300 feet (1 km) across. Observations also show JO25 rotates once every 4.5 hours.
2014 JO25 never posed a threat to Earth during its close pass as it didn’t get any nearer than about four and a half times the distance to the Moon. But it was the closest anything of its size has come to Earth since September 2004.
Because asteroids are typically quite dark (although JO25 is surprisingly bright) optical imaging is limited but they can be well observed using radar. By bouncing radar waves off them, astronomers can determine their shape, rotation, and where their surface is smooth or rough…and sometimes even see if they have any moons of their own! (JO25 does not.) The bright areas on this asteroid’s larger lobe, visible above, may be areas covered in large boulders.
2014 JO25 was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona, a project of NASA’s NEO Observations Program in collaboration with the University of Arizona.