When is an asteroid next predicted to hit the earth?

At present (May 2011) no asteroids are predicted to hit the Earth, at least not in the next hundred years, and possibly not even then.

------------------ Past possible encounters -------------------------

2002 NT7 [See related link]

A preliminary orbit suggests that 2002 NT7 is on an impact course with Earth and could strike the planet on 1 February, 2019 - although the uncertainties are large.

Astronomers have given the object a rating on the so called Palermo technical scale of threat of 0.06, making NT7 the first object to be given a positive value.

From its brightness, astronomers estimate it is about two kilometres wide, large enough to cause continent wide devastation on Earth.

This has now been downgraded and was removed from the list of potential objects.

99942 Apophis [See related link]

This was a likely candidate, and scored the highest ever on the Torino scale.

It has now been "downsized"