On November 6, 2009, The Catalina Sky Survey noticed something in the sky — an asteroid, seemingly on a collision course with Earth. The object would miss our planet by a mere 8,700 miles.
Terrifying? Hardly. Although the asteriod, identified as 2009 VA, would be the third-closest known (non-impacting) asteroid ever, it was also just 23 feet across. Similar sized objects pass this close to Earth about twice a year and impact the planet about once every five years.
The Nasa NEO programme aims to detect and track at least 90 per cent of the 1,000 asteroids and comets that approach Earth and are larger than 0.6miles in diameter, by 2020.
They monitored a 100ft asteroid that whizzed 45,000 miles above the Earth's surface on March 2 this year. A similar sized object slammed into Tunguska, Siberia in 1908. The impact created a blast so powerful it levelled 1,200 square miles of forest.
Read more about this asteroid at the Daily Mail.