It would be quite a weapon too!

I wonder if that strategy was considered during the cold war? I wouldn't be surprised.

In Soviet Russia asteroid saves world from you.

Against yourself?

Apophis is big enough to wipe out a large metropolitan area, but not much more than that, with plenty time to evacuate.

It could, however, excavate quite a crater that could become a very large water reservoir.

But I would prefer to do such major construction projects with nukes - the delivery time and positioning are much more controllable. Also, we have a whole lot of them sitting around and the freedom to use larger formats (they wouldn't have to ride on planes or missiles) could yield much cleaner ones too.

I suppose governments won't like the idea of civilians operating gigaton+ nukes, but that's something to be resolved between politicians and lobbyists.

I wonder how large an impact would be required to alter the earth's rate of rotation. I think we could all use a slightly longer day ;)

You could do that with a lot of smaller impacts. Also, it would be advisable to hit all major plates equally, to reduce the risk of major quakes on fault lines. If we were going to try to do it in one impact, we'd better evacuate the planet before too.

And have no plans to return in less than a couple hundred years.

It's only 350 metres wide. That'd be enough to seriously fuck up any large country on Earth without causing much damage, relatively, to other parts of the world. Anyway, you could keep the equipment on the rock, keep Apophis skimming Earth nice and close every few years, and have a permanent very big deterrent.

The deterrent wouldn't work. It would take ages to direct it to any target, but a much smaller time to neutralize it with a bomb.