Scientists will use dozens of telescopes around the world to collect as much data as they can as the asteroid passes.
Two asteroids - one almost a mile wide and and another, smaller one orbiting it - are rocketing its way through out solar system, and will pass close to the Earth (in astronomical terms, at least) on May 25. That distance is roughly 13.5 times further away than our own moon.More news: Trump Punches Back at Tillerson's 'Unprepared' Claims
NASA calculate it could have a diameter as large as three kilometres wide, or almost two miles, which would make the space rock capable of mass destruction.
For those looking to catch some views, EarthSky reports that the asteroid traveling more than 48,000 miles per hour should be visible for those with a telescope that is at least 8 inches in diameter.
The main asteroid is about a mile wide, and looks a bit like a spinning top thanks to a ridge that wraps around the rock's equator. The duo is expected to clear Earth at a distance of more than 3 million miles on Saturday evening, according to CNET.More news: Call of Duty: Modern Warfare campaign details: inspired by MW2’s ‘No Russian’
Various views of 1999 KW4 and its moon. Seventeen years from now, on May 25, 2036, the rocks will pass 55.2% closer to Earth, at a distance of just 1,443,511 miles (2,323,106 km) - again, posing no threat worth worrying about.
The asteroid, experts say will be visible from Saturday night (May 26) until Sunday (May 27). In fact, they won't even come close enough to see with the naked eye.
1999 KW4 was first discovered 20 years ago by the Lincoln Near-Earth Asteroid Research (LINEAR) observatory in Socorro, New Mexico. This will be the closest that a binary system has ever approached Earth.More news: ME confirms first case of measles in 2 years
"But most of us who are inexperienced observers with unsophisticated equipment may not be able to spot it".