This is CVS, I on the World. I'm John Bachelor with Gobert Schilling, his wonderful new book, The

Elephant in the Universe, 100 year search for dark matter.

Also, his travels and his conversations

with astronomers and researchers in deep minds,

in the beautiful chilly, high desert of Chile, and also back in time,

Gover is going to take us to the Big Bang and why it is that that's important to make part of the search for dark matter.

What happened in the first moments? What is it? How can we imagine it covered?

It's an extremely complicated topic, but we see now that space is expanding because all the galaxies get farther and farther away from each other.

So the empty space between galaxies is expanding.

That's something that we have measured over and over again. So if you try to work that back in time you must realize that in the past everything all the matter in the universe was closer together and if you go back in time

then it must have started in a very dense state and a very hot state and that's what the

storm was called a Big Bang which is actually the birth of our current universe.

Obviously, there are many, many riddles about the Big Bang.

We don't know why it started or how it started. We don't know the details, but we are pretty sure it must have happened. But now the problem is that if you start to study the remaining radiation of this hot phase, the cosmic background radiation, this radiation

radiation tells you something about the situation back then and you see that

universe must have been extremely smooth back then so maybe a little bit tiny differences in density but in general

very smooth like a well-stir soup, not much clumps and and concentrations in it.

But if we look at the universe today clumps and concentrations in it.

But if we look at the universe today,

only 14 billion years later, it's very clumpy.

We have galaxies, we have clusters,

we have big dense concentrations,

...