The three latest objects were all spotted first by the Mount Lemmon Survey, which searches for asteroids with a renovated 1.5-metre telescope in Arizona. Two asteroids were only a few metres in diameter, and the smallest was only about a meter, making spotting and tracking the objects in space an impressive achievement.

I would love to have seen the fireball from the one that entered the atmospere over Sudan. I bet it was awesome!

The good news is that bigger, more dangerous asteroids are brighter and easier to follow in the sky, so most of their orbits are known too well for them to surprise us by coming from out of the Sun. Next year, Canada will launch a small satellite that developers hope can spot asteroids inside the Earth’s orbit. US astronomers have proposed orbiting a satellite around Venus to hunt for such asteroids. But can we ever completely eliminate the danger of unknown objects?

So stop worrying about the LHC and worry about real threat from the skies!