A space rock almost twice the size of the Eiffel Tower is due to fly by the Earth on August 10.
According to NASA, Asteroid 2006 QQ23 is 570 meters (1,870 feet) in diameter and is traveling at speeds of approximately 16,740 kilometers per hour (10,400 miles per hour). It will come close enough to be classified as a near-Earth asteroid and is branded "potentially hazardous" – but astronomers are clear that there is nothing to fear from the celestial object.
To meet "potentially hazardous" status, an asteroid has to pass within a distance of 0.05 astronomical units from the Earth and at 0.049 astronomical units, Asteroid 2006 QQ23 only just meets the criteria. To put that into perspective, 0.049 astronomical units translates to 7.48 million kilometers (or 4.65 million miles).
As Lindley Johnson from NASA's Planetary Defense Coordination Office told CNN, it is "more or less benign". Around six objects of its size come this close to Earth in any one year, so it is nothing out of the ordinary. An impact is a much rarer event and only takes place once every two or three centuries, Johnson added.
An impact on that scale would be extremely rare, but we know that a risk exists. Over the last century and a bit, we have collected evidence of several large meteors entering our atmosphere, and many more are likely to have dropped into the sea unnoticed. For example, only last month, a suspected meteor crashed into an Indian rice paddy. The resulting hole was just 1.5 meters (5 feet) deep and no one was harmed.
On a slightly larger scale, a meteor came tumbling towards Earth at speeds of 32 km (20 miles) per second late last year, hitting the Earth's atmosphere above the Bering Sea shortly before the holidays. Despite being the largest "hit" since the 2013 Chelyabinsk explosion in Russia and exploding with 10 times the energy of the atomic bomb that hit Hiroshima, it went virtually unseen – only noticed because it was picked up by US military satellites.
Johnson told reporters at the time that impacts with meteors of that size (10 meters or 33 feet) occur just once every two or three centuries.
NASA estimates there are some 900 near-Earth objects of more than 1,000 meters (3,280 feet), which – if they were to crash in the wrong place – could do a fair amount of damage. Indeed, a simulation involving space rock measuring 50-80 meters (165-260 feet) left New York City in ruins.
