Dancing in the Dark: The End of Physics? Page #2

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speed as the stars in the centre.

Wherever the speed of stars

in spiral galaxies were measured,

they produced the logic-defying

flat rotation curves.

The only way they made sense was

if there was more matter than

we thought, producing more gravity.

And since the extra stuff

couldn't be seen, it was given

the slightly sinister title

"dark matter".

Dark matter is a really

interesting problem.

It sounds exotic, but

it doesn't have to be.

Professor Katie Freese is

a theoretical physicist.

That is to say, the physics

she deals with is theoretical.

Katie herself is real.

There's a lot of dark things out

there in the universe.

Until I shine my light at these

bottles, I can't see them

and as soon as I take away

the light, they're dark.

That's what people thought. They

thought it might be gas,

it might be dust.

The dark matter could just be

ordinary stuff that you can't see.

These ordinary, but dark, dark

matter creatures are called MACHOs -

massive compact halo objects.

But the trouble was that even

the most generous

estimates for how much the MACHOs

might weigh fell pathetically

short of what would be needed to

explain the strange

goings-on in spiral galaxies

like ours.

Another explanation was required.

Well, there's an alternative idea

for what the dark matter could be.

What we think it is, is that it's

some new kind of fundamental

particle. Not neutrons, not protons,

not ordinary atomic stuff

but something entirely new.

And these particles are

everywhere in the universe.

They're flying around in our galaxy,

they're in this room.

Actually, there would be billions

going through you every second.

You don't notice, but they're there.

These theoretical dark matter

candidates are called WIMPs -

weakly interacting

massive particles.

But because they interact weakly

with ordinary matter,

the stuff from which we and

scientific instruments are made,

catching them is about

as straightforward

as trapping water in a sieve.

In fact, in the early days of dark

matter, these particles were

so theoretical that no-one had any

idea at all about how

they might get hold of one,

even in theory.

Then, in 1983, freshly minted

theoretical physicist

Katie Freese had an epiphany.

I was at a winter

school in Jerusalem

and that's where I got into

the dark matter business.

I met a man named Andre Drukier.

He's a brilliant, eccentric person.

He's Polish,

he speaks English, French,

German, Polish,

all at the same time.

And he knew where to

go for the New Year's party.

And he started, believe it or not,

in that evening,

over the cocktails -

cocktails have always been

good for science -

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