Toward the end of 2004, I plotted out a new walking route around my neighborhood.

I've been trying to get in a good three miles as many days a week as the weather in my schedule will allow.

This takes me about 45, 50 minutes,

which is just about the length of a podcast episode,

but which podcast should I listen to?

Well, when I was planning this new route,

I was thinking a lot about science.

I'm not just a history guy, you know.

And there are some topics like quantum physics

that are fascinating and complex enough

that I need to go over the material

a few times. You know, it's okay to be uncertain about the uncertainty principle.

So I sampled a pretty large range of podcasts, and as you might imagine, I'm kind of picky.

But I found one show that asked some fundamental questions.

What is time? What is a particle? And did them really well.

They also

tackled some not so fundamental questions like how does memory work and are humans still evolving.

And because the hosts are both real working scientists and great communicators, the show is a

delight. But then I stopped walking that route. I fell out of the routine of listening.

So I'm delighted to be reunited

with my old favorite science podcast today and sharing it with you. On today's Saturday

matinee, we're bringing you an episode from the Three Mile Walk Approved podcast, Daniel and

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