Humanity has survived yet another cosmic close encounter with a huge asteroid.
A space rock the size of a double-decker bus zoomed Earth and moon at a distance of just 139,433 miles, which is close enough for astronomers to consider it a ‘near miss’. Asteroid 2017 YZ4 was never threatening to wipe out our species and is about 15 metres wide, which is not large enough to cause damage on a global scale. An asteroid called the Chicxulub impactor, which killed off the dinosaurs, is thought to have been between 10 and 15 kilometres in size. However, you wouldn’t want to be standing nearby if YZ4 smashed into Earth. It’s comparable in size to the object which exploded in the sky over the Russian town of Chelyabinsk, generating a flash of light as bright as the sun and producing a shock wave which shattered windows across the city and left more than 1000 thousand people injured. The newly-discovered asteroid was only spotted on Christmas Day, before speeding past Earth at 21,000mph on December 28.
If it was on a collision course with our planet and was big enough to cause serious damage, this late discovery would not have left governments enough time to evacuate cities which are in the firing line. An asteroid is considered ‘hazardous’ if it’s predicted to come within 4,600,000 miles of our planet. Astronomers monitor hundreds of asteroids as they travel around our solar system, which means it’s unlikely an object large enough to cause an ‘extinction-level event‘ would evade their attention. A Nasa spokesman told The Express: ‘This is the first known asteroid to flyby Earth within one lunar distance since two such asteroids flew past us 35 minutes apart on November 21, and the 52nd this year. ‘As of December 24, there are 17,495 known near-Earth objects (NEOs) around our planet.17,389 are asteroids. ‘This year, we discovered 1,985 new near-Earth asteroids. There were 1888 such objects discovered in 2016 and 1,571 in 2015.’