The rather unimaginatively named 481392 (2006) SF9 asteroid measuring around 2,034 feet rushed past the Earth at an incredible 17,800 miles /hour on 20th November 2019.
The giant rock has a diameter of 2,034 feet and came to within 2.7million miles of the planet we call home. According to NASA, this is a distance 11 times greater than the distance between the Earth and the Moon. This is likely to be the closest the asteroid will get to our planet for at least for the next 200 years.
The giant asteroid was first seen by astronomers near Tucson, Arizona back in 2006. The Catalina Sky Survey is run by scientists based in the Steward Observatory and aims to look for asteroids, comets, and meteors.
Despite the huge distances involved this giant asteroid is known as a NEO (Near-Earth Object) because it came within 121 million miles of the sun and 30 million miles of our own planet’s path around the star.
There are numerous other types of NEOs but asteroids are the most common and are only considered "potentially hazardous" in certain circumstances. NASA would start to become concerned about an asteroid if it came to within 4.6million miles of Earth and had a size over 460 feet. This is about 19 times the distance between the moon and the earth.
It seems then that 481394 (2006 SF6) is seen as a potential hazard and certainly if it did hit the Earth there would be devastating results. That said, it is not considered likely to hit the Earth within at least the next 200 years and, despite its size, the asteroid is still too small to cause the sort of extinction-level event that wiped out the dinosaurs even if a collision occurred.
There are around a quarter of a million NEOs larger than 460 feet at present, yet, according to NASA this probably represents only 35% of the total figure of asteroids in circulation. Once you start looking at the smaller objects, those with a diameter of under 33 feet, you start to see figures shoot up to the 100 million range.
There are likely around 5,000 asteroids that could prove to be a hazard.
An asteroid consists of debris that was leftover for the early formation of the solar system. Most of the material joined together to form planets but some are still floating around out there. These asteroids give us valuable insights into how our solar system originated and shows that even now, around 4.5 billion years later, it is still changing and evolving.