A large asteroid designated 2014 JO25 will safely flyby Earth at a distance of 4.6 LD (1.76 million km / 1.09 million miles) on April 19, 2017. This is the closest approach by any known asteroid of this size, or larger, since asteroid Toutatis in September 2004.
2014 JO25 was first observed at Mt. Lemmon Survey on May 5, 2014, and it belongs to the Apollo group of asteroids.
The estimated size of this near-Earth object is between 640 m and 1.4 km (0.39 - 0.86 miles). It will flyby Earth at a speed (relative to the Earth) of 33.56 km/s at 12:24 UTC on April 19.
Contemporary measurements by NASA's NEOWISE mission indicate that its surface is about twice as reflective as that of the Moon. Even though its trajectory is well known, very little else is known about the object's physical properties at this time.
According to NASA's Jet Propulsion Laboratory, 2014 JO25 will approach Earth from the direction of the Sun and will become visible in the night sky after April 19.
It is predicted to brighten to about magnitude 11, when it could be visible in small optical telescopes for one or two nights before it fades as the distance from Earth rapidly increases.
Small asteroids pass within this distance of Earth several times each week, but this upcoming close approach is the closest by any known asteroid of this size, or larger, since asteroid Toutatis, a 5 km (3.1 miles) wide asteroid, which approached within about 4 LD (1.53 million km / 0.95 million miles) distances in September 2004, JPL said.
The next known encounter of an asteroid of comparable size will occur in 2027 when the 800 m (0.5 miles) wide asteroid 1999 AN10 will flyby at 1 LD (380 000 km / 236 000 miles).
The April 19 encounter provides an outstanding opportunity to study this asteroid, and astronomers plan to observe it with telescopes around the world to learn as much about it as possible. Radar observations are planned at NASA's Goldstone Solar System Radar in California and the National Science Foundation's Arecibo Observatory in Puerto Rico, and the resulting radar images could reveal surface details as small as a few meters.
The encounter on April 19 is the closest this asteroid has come to Earth for at least the last 400 years and will be its closest approach for at least the next 500 years.
Featured image credit: NASA/JPL