Thanks to Hollywood most of us have an image in our minds of how a large asteroid impact would effect Earth.  I know I've got several in my head this week.

A 1,300-foot asteroid is going to pass within 0.85 lunar distances of the Earth later next week.  That's pretty close, inside the moon's orbit.  It's named 2005 YU55 and is roughly the size of an aircraft carrier.

This is the most significant near-miss scientists have known about in advance.

The asteroid will be tracked by NASA's Deep Space Network.  They hope to gain more insight about it, mainly composition.  The asteroid is roughly spherical in shape and spins slowly.  It's rotation period is about 18 hours.

It's expected to reach it's closest point to Earth next Tuesday when it will be as close as 201,700.  That's as close as its come in 200 years.

For more see this source article.