What is the Likelihood of an Asteroid Impact?

We certainly know that we were hit 65 million years ago by a very large rock from space. Hollywood made two blockbusters, “Armageddon” and “Deep Impact,” so it must be true. 

It was really interesting, in ’95, Spielberg sent his minions to a conference to where a number of us were attending about this particular hit and indeed, there is a great danger out there.  We are surrounded by asteroids, some become Earth-crossing.  Jupiter has a way of perturbing comets and sending them from stable orbits to Earth-crossing orbits.  We will get hit again.  How big the hit will be is only a matter of time until we get something the same size that killed off the dinosaurs, should humanity last long enough, that is. 

But that size hit looks like only once every 100 million years, or more.  We haven’t had a hit that size for the last 500 million years.  So, it does look like it is a rare event to have something that big – a 10 kilometer asteroid hit us. 

In Their Own Words is recorded in Big Think’s studio.

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