From the Wikipedia...

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Possible impact effects

It must be stressed that the odds of impact are now known to be very low. Hence, the possible effects of an impact are largely irrelevant.

However, the initial reports resulted in widespread discussion on many Internet forums, including armchair speculation about exactly where Apophis (then known only as 2004 MN4) would hit and what would happen when it did.

NASA initially estimated the energy that Apophis would have released if it impacted Earth as the equivalent of 1480 megatons of TNT (114,000 times the energy from the nuclear bomb Little Boy, dropped by the United States on Hiroshima, Japan). A more refined later estimate was 870 megatons (which is still around 65,500 times the energy of the bomb mentioned above). The impacts which created the Barringer Crater or caused the Tunguska event are estimated to be in the 10-20 megaton range. The 1883 eruption of Krakatoa was the equivalent of roughly 200 megatons.

The exact effects of any impact would have varied based on the asteroid's composition, and the location and angle of impact. Any impact would have been extremely detrimental to an area of thousands of square kilometres, but would have been unlikely to have long-lasting global effects, such as the precipitation of an impact winter.

Based on the predicted time of impact (0.89 of a day, or about 21:20 UTC) and the fact that the asteroid would be approaching the Earth from outside of its orbit, the impact was likely to occur in the Eastern Hemisphere (time zones UTC +3 to UTC +10).

Any potential impact would have occurred at a velocity of 12.59 km/s

One more reason we'll have to invade Iran.

That's scary shit. Couldn't we use something like a scalar wave interferometer to sway its course? I think the idea of a bomb being sent out to intercept it would be impractical. At least with longitudinal wave tech, getting an energy burst from point A to point B shouldn't be an issue. Geez, day after day my future becomes more uncertain.... I'm gonna crawl back into my mother's womb. See you guys later..................