Back on May 25, 2001, according to NASA, the asteroids passed about 6.7% closer to Earth than they will this time, at a distance of 3,005,447 miles (4,836,798 km). NASA's asteroid trackers are braced for the space rock to shoot past our home planet around 12.05am United Kingdom time in the wee hours of Sunday, May 26.
The asteroid, known as 1999 KW4, will make its closest approach to our planet on Saturday, but it's important to note that that distance means something different to space folks, who work on a galactic scale. The larger one is just under a mile in diameter and its companion asteroid "moon" is about a third of that size.
While the near-Earth object is classified as a potentially hazardous asteroid, there will be a cushy 3.2 million miles between Earth and the walnut-shaped space rock during its closest approach.
Despite its "potentially hazardous" classification by the Smithsonian Astrophysical Observatory's Minor Planet Center, Asteroid 1999 KW4 is expected to pass by Earth safely at 23:05 UTC.
Earth will be getting not one but two visitors from space this weekend. It is believed that the YORP effect is also one of the causes for the creation of binary asteroids such as the 1999 KW4.
During this timeframe, the asteroid often crosses paths with the Earth's own obit of the Sun.
NASA ambassador Eddie Irizarry of the Astronomical Society of the Caribbean confirmed the asteroid will not be visible to the naked eye, but encourages amateur astronomers to try to spot it as it passes Earth. The asteroid won't pass this close to earth again until 2036. They recommend heading over to EarthSky to learn how you can see 1999 KW4 for yourself.
The 1999 KW4 was discovered, as its name suggests, on 20 May 1999, by Lincoln Near-Earth Asteroid Research (LINEAR) project. "And that's when it will be at its very closest to Earth".