If E.T. Comes Calling

So what happens if the aliens land? Here, on Earth.

I'm not talking about detecting a radio signal or a laser flash from hundreds of light-years away. I'm speaking of visitors who actually set their boots on the ground. What do we do?

It may surprise you to learn that there's precious little preparation for such an eventuality.

Now if you're among the many tens of millions of Americans who think aliens are already afoot in the land, you're confident you know humanity's reaction. Scoffing denial.

But face it: Few scientists are convinced by the evidence offered for visitation. So let's consider the question assuming that the extraterrestrials aren't here.