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A Bill Moyers Special - Becoming American: The Chinese Experience

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About The Programs } Personal Journeys: Transcript

Public Affairs Television "Becoming American" Interview with Sam Ting

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BILL MOYERS: Well, thank you for doing this. Someone told me that you are looking for the missing half of the universe. Is that right?

SAM TING: You can interpret it that way. What we are doing is we have an experiment on the international space station. And the idea is very simple. If you believe the universe came from a big bang and before the big bang there's nothing.

So at the beginning of the big bang if you have an electron you must have a positron. And if you can have a quark, you must have anti-quark. And so if you have a matter you must have an equal amount of antimatter.

BILL MOYERS: Antimatter. I've never understood that term.

SAM TING: Antimatter was proposed by Paul Dirac, a physicist in 1928. He received a Nobel Prize in 1933. Antimatter is the same as matter except everything is just opposite. If a matter have positive charge antimatter have negative charge. So, all the properties are just the opposite.

But when they meet they annihilate each other and become light. Antimatter we know exists on Earth. If you go to the hospital you take a positron tomography and that's positron, which is the antimatter of electron.

So, the existence of antimatter-- there's no doubt 'cause we know the accelerators will produce them. The question is if the universe came from a big bang, is there a universe made out of antimatter?

BILL MOYERS: I only passed science in college because I persuaded my lab instructor who was older to date me. And she had a benevolent attitude toward me and she tolerated my ignorance. I am an ignoramus when it comes to science. So, to a layman what is antimatter? What is it you're looking for?

SAM TING: To a layman-- it's more difficult to explain. We know the universe came from a big bang because if you look through telescope, you see the stars and galaxies move away from each other. This was discovered by Hubbell, so the universe is expanding.

Tomorrow the universe will be larger than today. Next year it will be larger than this year. This is what expanding means. So, the converse is that last year it was smaller than this year. And so from this you can trace back about 14 billion years ago the universe came from a point. And that's the idea of the big bang.

BILL MOYERS: From a point?

SAM TING: Yeah, from a point. 'Cause you can, just from the rate of expanding or the rate of shrinking, go back in time. And from this you will see the universe came from a big bang.

Now, at the beginning, before the big bang, this vacuum, there was nothing. So, if you have an electron which carries a negative charge you must have something that carries a positive charge to balance it out. And that's how you have the antimatter.

BILL MOYERS: No wonder you're a teacher. Now, I see that but I still don't understand it because-- I mean, how can there be a vacuum with nothing in it if there's an electron in it?

SAM TING: No. In the beginning, there was nothing.

BILL MOYERS: Just nothing?

SAM TING: Nothing. And then there's something called— Suddenly, the universe exploded from a positive particle and a negative particle that put it this way. And then if the universe is made out of positive matter then there must be a universe made out of negative matter.

BILL MOYERS: And you're looking for that negative matter?

SAM TING: Yeah. But positive or negative is a relative thing. You can call the negative one the matter. If the one we live is antimatter, then the other one will be matter. That's a relative thing.

BILL MOYERS: How can you look for something you can't see?

SAM TING: You cannot see it because they're either too small or moving too fast. How do you detect an antimatter? You detect the matter by measuring its charge. And matter has a positive charge, positive mass. Antimatter will have negative charge. So you have the same mass but negative charge. And so if you measure that then you know the antimatter exists.

BILL MOYERS: Is it like looking up at the sky after a plane has passed and seeing the trail?

SAM TING: Yeah, exactly. Exactly like that.

BILL MOYERS: So, how do you propose to find it?

SAM TING: When antimatter and matter meet they always annihilate each other, so you cannot measure them on the ground. When you go through the Earth's atmosphere, antimatter will be annihilated 'cause the Earth's atmosphere is very dense. And so you have to go to space. That's why we do this experiment on the NASA space station.

BILL MOYERS: So, what are you building right now?

SAM TING: We're building a rather large spectrometer, which is a device that measures the charge and measures the mass of a particle./p>

BILL MOYERS: Is this a magnet?

SAM TING: Outside it's a magnet and inside are various detectors and you can measure the property of particles.

BILL MOYERS: So, you'll be in effect sending a magnet into space--

SAM TING: Yes, to measure the particles.

BILL MOYERS: Where is the thing right now?

SAM TING: The thing has been built in England, in Switzerland, in France, in Germany. There are a total of about 16 countries working together because it's a fairly difficult thing to do. Nobody has done this before. And it's quite large. It's about seven tons and is about three feet by three feet. Inside there are about 300,000 various detectors.

BILL MOYERS: When it is built, what happens to it? Where does it go?

SAM TING: NASA will have a space shuttle to take us from Kennedy Space Center to the space station and then astronauts will use the arm from the shuttle to move to the space station. And then we will be in the space station for about three years.

BILL MOYERS: Given the recent tragedy with Columbia do you still think it will happen three years from now?

SAM TING: It could take a little bit longer. I don't think NASA should fly the shuttle until they've found out what was wrong. And so maybe it will take a year longer. And we've been planning to finish the detector about the middle of next year. What we're gonna do is we're gonna test it extensively on the ground. We're going to simulate the condition of space, go through a vacuum, go through a temperature change and vibrate the detector, simulate the shuttle leaving the ground, to make sure it works. So, it will give us one more year for more testing.

BILL MOYERS: This is a great risk, isn't it? I mean, it's not been done before you said.

SAM TING: No, it's not been done before. And it is not an easy thing to do. You need to think through carefully what you're doing.

BILL MOYERS: What's the risk? I mean-- even a tiny mistake in space, that's it, right?

SAM TING: Yes. And therefore there are two things you have to do. One is you have redundancy. Okay, we have a lot of microprocessors. On the ground maybe you need only one computer in space and you put in four, five, six, seven of them. And if one is bad you switch to the next one and switch the next one, switch to the next one. The second thing is before you send it to space, you do extensive tests. You simulate the condition of space.

BILL MOYERS: I mean, there's no book you can read is there to help you with this?

SAM TING: No, but you can think.

BILL MOYERS: How do you think about something for which there are no pictures, there's no book, there's no precedent? Is it pure logic?

SAM TING: Logic is important. And experience. Before we did this experiment we have done many experiments under ground. And so we know under what condition a detector is reliable and what risks you should take or not take.

Experience sometimes is important. You cannot guarantee anything. And this is why before we sent the one on the space station, NASA flew our detector on a space shuttle once. It turned out it was okay.

BILL MOYERS: Help me to understand how you think about something like this. You sit in your laboratory and walk yourself through a series of imagined steps. How do you do that?

SAM TING: That's hard to say how you think. I talk to people. I have many collaborators collaborating with me. There are about a few hundred physicists from 16 countries. I talk to them. And I ask them to come to meet with me once every three months.

Once every three months everybody comes to Geneva, Switzerland where we have a meeting. I make sure we hear from the laboratory directors, from the professors, from the assistants. Even the newest graduate students present their opinions. I listen very carefully. Physicists seldom agree with each other. (LAUGHTER)

BILL MOYERS: I'll take your word for it.

SAM TING: So I listen very carefully to everybody's opinion and then make a decision as to what to do.

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