哈尔岑获诺贝尔物理学奖：他把南极的冰变成了捕捉幽灵粒子的望远镜

Right now, more than a billion tiny, tiny things are passing through your hand.

You can't feel it at all.

These tiny things are called neutrinos.

Neutrinos are extremely small; they can pass through your hand, through your room, and even through the whole Earth.

Because neutrinos can pass through anything, scientists have always found them very hard to see.

On October 6th, a scientist won this year's Nobel Prize because he saw neutrinos.

His name is Halzen; he's Belgian, works at a university in America, and is eighty-two this year.

His prize is the Nobel Prize in physics.

This year's physics Nobel went to him alone.

So how did Halzen see neutrinos?

His method is in the coldest place in the world: the South Pole.

The South Pole has lots and lots of ice, and the ice is very thick.

In 1988, Halzen thought: we can use the ice at the South Pole to see neutrinos.

Scientists drilled eighty-six very deep holes in the ice at the South Pole.

In the holes, they placed 5,160 sensors.

A sensor is a kind of small machine that can see light.

These sensors are about two thousand meters under the ice.

Scientists gave this big project a name: IceCube.

Most neutrinos pass through the ice and leave nothing behind.

But sometimes, a neutrino in the ice gives off a tiny bit of blue light.

When the sensors see that tiny bit of light, scientists know: a neutrino has arrived.

Scientists can also tell where in the sky the neutrino came from.

In 2013, IceCube saw twenty-eight neutrinos.

These twenty-eight neutrinos didn't come from the sun; they came from somewhere very, very far away.

It was the first time people had seen neutrinos from so far away.

Before, we used our eyes and light to look at things in the sky.

Now, we can also use neutrinos to look at things in the sky.

That's why Halzen won the Nobel Prize.

From thinking of this idea in 1988 to winning the prize today, he waited thirty-eight years.

Do you remember Jun Ye?

Last week we said Jun Ye might win the Nobel Prize.

This year's physics Nobel went to Halzen.

Think about it: if you could go to the South Pole, what would you most want to see?