Have you listened to Talk Radio recently?

Let's talk about this war on white people.

That's a pro-quiling, it's good for you.

Bill the Keystone pipeline, deport illegals, build the wall.

I'm Katie Thornton, host of the divided dial,

a new five-part series from WNMC's On the Media,

about how the American right came to dominate Talk Radio

and how one company is launching a conservative media empire

from the airwaves.

Listen every Tuesday and on the media feed.

Hi everyone, welcome to the Ted interview.

I'm Stephen Johnson.

If you look back over the past few centuries,

it's clear we've solved many of the major mysteries in science.

I mean, we've sequenced the human genome and split the atom.

We can detect radiation that dates back to the big bang.

But every now and then, we get reminded that there are still some big questions out there

that remain unanswered.

Take for instance the discovery just a few decades old,

that the overwhelming majority of the universe is made up of some mysterious substance.

A substance we can't perceive directly using any of our existing tools,

and which doesn't seem to belong to any of our known categories.

...