A massive asteroid zoomed terrifyingly close to Earth and no-one knew it was coming

It's nice to think that NASA's team of astronomers are keeping a watchful eye on all those doomsday space rocks floating through space.

But it turns out that asteroids can be so difficult to spot that one could sneak up and wipe out humanity before we've even had time to say our collective prayers.

Last Sunday (August 28) a huge asteroid dubbed 2016 QA2 zoomed past Earth at terrifyingly close quarters, coming within 50,000 miles of our lovely home planet.

Nothing to worry about, you might think, until you hear that it was only

This asteroid was relatively small with a width of of between 25 and 55 metres, but that would still be enough to cause damage down here on Earth if it smashed into the atmosphere.

A slightly smaller rock exploded in the air over the Russian city of Chelyabinsk in February 2013, leaving more than 1,200 people injured.

To wipe out humanity, an asteroid would have to be about 0.6 miles wide.

Scientists have identified about 95% of these doomsday space rocks, but that leaves us with the possibility that there's one great big asteroid out there with our name on it.

Let's hope it doesn't sneak up on us like 2016 QA2 did.