A giant “planet killer” asteroid will pass very close to Earth on June 27, hurtling past our planet at about 58,000 mph (93,000 km/h). This “potentially hazardous” object, which is comparable in size to a mountain, is one of the largest space rocks to come this close to Earth in more than a century — and you can watch this close encounter live.
The asteroid, known as 2011 UL21, is classified as a near-Earth asteroid, meaning its orbit periodically brings it within 1.3 astronomical units (AU) of the sun, or about 1.3 times the average distance between Earth and the sun. It completes one orbit around our star once every three years. According to SpaceReference.org, estimates based on previous observations put its diameter between 1.1 and 2.4 miles (1.7 to 3.9 kilometers), making it larger than 99% of all near-Earth asteroids, the report noted. European Space Agency(ESA)
2011 UL21 is estimated to be at least ten times smaller than the largest space rocks to hit Earth, such as the Vredefort asteroid, and about five times smaller than the asteroid that is believed to have caused the extinction of the dinosaurs about 66 million years ago.
Despite its small size compared to these historical impacts, 2011 UL21 is still classified as 'potentially hazardous' because it has the potential to cause widespread damage. It has the potential to release enough debris into the atmosphere to cause continental-scale damage and induce significant climate change.
On June 27, 2011, UL21 will pass by Earth at a distance of about 4.1 million miles (6.6 million km), the closest it has been in at least 110 years, according to simulations by NASA's Jet Propulsion Laboratory (JPL). Because of this proximity, NASA classifies it as a potentially hazardous object, although it is about 17 times farther from Earth than the moon.
Although 2011 UL21 currently poses no threat to Earth, it is notable as one of the largest asteroids to come within 4.7 million miles (7.5 million km) of our planet since 1900, said Gianluca Masi, astronomer and director of the Virtual Telescope Project (VTP).
You can watch 2011 UL21's closest approach via a free livestream provided by VTP, which includes views from the Bellatrix Astronomical Observatory in Ceccano, Italy. The livestream begins at 4 p.m. ET on June 27, and closest approach is expected about 15 minutes later.
For those with suitable binoculars, the asteroid will be brightest on June 28 and June 29, visible from the Northern Hemisphere under optimal conditions. At its maximum brightness, it will shine as brightly as Proxima Centauri, the nearest known star to the sun, VTP noted.
2011 UL21 won't get this close to Earth until 2089, when it will come within 1.7 million miles (2.7 million km) of our planet — two-and-a-half times closer than it currently is, according to JPL simulations.
There is no predicted risk of any known “planet-killer” asteroid hitting Earth in the next 1,000 years. However, close encounters with smaller asteroids are expected in the coming years, such as asteroid Apophis, which is potentially large enough to devastate a city and will pass closer to Earth than some satellites in 2029.
Today's featured video
“It is important that the voice of the opposition is also given a voice”: Rahul Gandhi to Om Birla