Chunky asteroid heading our way, set to narrowly miss us on Monday.

The following is an excerpt from a Discovery News article:

This may sound like late notice, but astronomers have just spotted a rather chunky asteroid heading our way, set to narrowly miss us on Monday.
In fact, it will be such a narrow miss that astronomers in the Southern Hemisphere should be able to spot the flyby with fairly modest telescopes.
Coincidentally, I was watching yet another re-run of Armageddon the other night when the heroic Bruce Willis and his motley crew of oil drillers-turned-astronauts saved Earth from certain asteroid doom. On arrival at the asteroid, and having sacrificed many of the team, Willis et al. succeeded in dropping a typical Hollywood-style uber-bomb into the depths of the incoming asteroid and blew it to bits, giving everyone on Earth a glitzy meteor shower.
I’m not so sure it will be really that easy to destroy an incoming asteroid (see my previous Discovery News article “How do we dodge the next incoming asteroid?“) particularly given the 12 days notice they had in the film.

The Daily Mail reports:
An asteroid the size of a large house will zip within 8,000 miles of Earth at about midday on Monday.
That’s at least double the size of the asteroids that have previously been observed so close to Earth.
Called 2011 MD, the asteroid was discovered late on Wednesday by an automated asteroid-hunting telescope run by the MIT Lincoln Laboratory’s LINEAR programme, which has already discovered more than 2,000 near-Earth objects. Within 24 hours, four other groups confirmed the discovery, according to the New Scientist website.
The Minor Planet Center at Harvard University does not rate 2011 MD as potentially hazardous because its size – calculated from its brightness – is estimated to be betweein 24ft and 55ft. That would make an impressive explosion if it hit the atmosphere, but it wouldn’t reach the ground.
On its current pass, 2011 MD won’t hit Earth’s atmosphere. It will come inside the orbits of many communications and spy satellites, but will still be some 7,750 miles away from the International Space Station. However, Spaceweather.com reports that the encounter is close for Earth’s gravity to ‘sharply alter the asteroid’s trajectory’.