This was 8 days early.
We (and that I mean the ‘Catalina Sky Survey‘ in Tucson, Arizona) only discovered it 24-hours prior to that! Yes, you read that right. It came straight out of the blue just 24-hours before whizzing by us. I have always claimed that this is the problem we will have with asteroids and comets. What we have to worry about are the ones that sneak up upon us like this one.
It was pretty big. Around the same size as the meteoroid that exploded above Tunguska, Russia in June 1908. If this had hit Earth, or exploded in the atmosphere, it would NOT have wiped us all out. But, it would have caused a huge amount of devastation.
As it says above: “It is the largest known asteroid to ever pass that close to Earth in observational history!”
Check Category ‘astronomy’.