Robert Krulwich

With glaciers melting and crumbling all over the world, let me tell you the story of the man who first imagined ice ages, the man buried under this stone in Cambridge, Mass. It's an odd gravestone; a rough, clumpy hunk of granite that doesn't look at all like the other markers at Mt. Auburn Cemetery.

That's because it isn't. It's an erratic. A single stone found sitting downhill from a glacier in Switzerland that was lifted, packed, shipped to all the way to Massachusetts to honor this man.

This is for you, Martina Navratilova, for you, Nolan Ryan, for you, Methuselah, for you, Jimmy Carter, and for all of you reading this if you're on the "wrong" side of 50 but still pumping. This week, we've got ourselves a role model, a poster boy for robust old age.

We'll start in a cornfield — we'll call it an Iowa cornfield in late summer — on a beautiful day. The corn is high. The air is shimmering. There's just one thing missing — and it's a big thing...

...a very big thing, but I won't tell you what, not yet.

Instead, let's take a detour. We'll be back to the cornfield in a minute, but just to make things interesting, I'm going to leap halfway around the world to a public park near Cape Town, South Africa, where you will notice a cube, a metal cube, lying there in the grass.

This is your brain making things up.

What you see isn't really there.

There are people (and I hear from them constantly) who think if a subject is sophisticated, like science, the language that describes it should be sophisticated, too.

If smart people say torque, ribosome, limbic, stochastic and kinase, then the rest of us should knuckle down, concentrate and figure out what those words mean. That's how we'll know when we've learned something: when we've mastered the technical words.