So I'm out on my bike and I see a UHaul van parked on the road. I like the artwork they put on the sides of the vans; it's always about some attraction from a specific state. In this case, the state was Iowa, and I was pretty surprised to see this picture:
How cool is that? 70 million years ago, Manson, Iowa got smacked hard by a rock that must have been a few kilometers across at least; the crater is over 40 km in diameter.
But what's totally cool is they put an equation -- an actual equation! -- on the van:
How hawesome is that? I didn't know what the terms in the equation are for (this ain't my bag, baby) so I asked my buddy Dan Durda, about whom I have talked extensively in the past. He studies asteroid impacts, and told me that the equation gives you how far the ejecta -- the splattered materials from the impact -- will travel. Rb is the ballistic range of the material, or how far it will travel (neglecting air resistance and such). Rp is the radius of the planet -- in this case, Earth. Ve is the speed (not velocity, and Dan threatened me over this, so I wanna be very clear) the material is ejected, g is the Earth's gravity, and Φ (the Greek letter phi) is the angle from horizontal at which the material is ejected. When you crank all that stuff through (and don't forget the arctangent!) you see how far the impact throws material.
Even more cool: this equation accounts for the curvature of the Earth. There is a simpler version that assumes a flat surface, but UHaul chose the more complex one.
I think it is totally excellent of UHaul to do this-- I learned stuff, and I love to learn stuff.
You can learn more about Manson here, if you want some snark with it. UHaul has a t-shirt with the Iowa art on it for sale too. For $10 it ain't bad.