B. Journey to the Center of the Earth

Narrator: This is Science Today. Physicists at the Lawrence Livermore National Laboratory have developed a technique to journey to the center of the Earth. Jeffrey Nguyen explains there's obviously no physical way of doing this, but what you can do is generate conditions that are similar to that at the core of the Earth.

Nguyen: What we have done is we used a two-stage gas gun by launching a projectile up to eight kilometers per second and at that velocity, you can generate conditions exceeding that at the center of the Earth and for a brief moment in time – a couple of nanoseconds – the conditions inside the center of the Earth is obtained and you do your measurement in that short period of time.

Narrator: The projectile that Nguyen and his colleagues used is a piece of metal shaped like a coin that is very light on one side and heavy on the other.

Nguyen: And so what you can do essentially is start out where we are on the surface of the Earth and essentially push our way straight through the pressure that's equivalent to where it is in the center or the Earth.

C. Deciding When to Go to the Emergency Room

Narrator: This is Science Today. Part of what's been driving emergency room visits up in this country is an increased awareness and push to make sure that patients who need urgent care are getting it. On the other hand, Ellen Weber of the University of California, San Francisco's Division of Emergency Medicine, says it's sometimes difficult for patients to know, for example, whether their chest pain is resulting from a heart attack or just indigestion.

Weber: Nobody should feel foolish about coming to an emergency department. It's not the job of the person who is not a medical person to decide for themselves that they have an illness that does or doesn't need treatment. If they have a new symptom and they just need reassurance, I don't think that's a bad reason to come to an emergency department.

Narrator: The key, Weber says, is to put it into context.

Weber: If I have a pain in my arm or my leg, I go in my own head – well, this is probably not a stroke. But I've always told people they should never feel silly about discovering that they don't have a serious problem – that's what we're here for.

Narrator: For Science Today, I'm Larissa Branin.

D. How MRI Technology May Be Used in Agriculture

Narrator: This is Science Today. Using technology borrowed from the medical field, University of California agriculture engineers have developed a new device for detecting freeze damaged citrus fruits without having to cut them open. Agricultural engineer Jim Thompson says the device was built to measure water quality content and uses the same principle as magnetic resonance imaging.

Thompson: When the fruit has been frozen, the cell structure is disrupted compared with normal fruit and the magnetic resonance signal will detect the fact that the water is held different in the fruit cells in those areas where the fruit cells have been damaged by freezing.

Narrator: But as in the medical field, an MRI-type fruit scanner would be expensive.

Thompson: At this point the magnetic resonance imaging cost in the range of about forty thousand dollars, which is fairly expensive. Although, some of the detection systems we use now in packing lines are about that same cost. So while it is expensive, if it's accurate, it would be worthwhile.

Narrator: For Science Today, I'm Larissa Branin.

E. New Insight into What Triggers Deep Earthquakes

Narrator: This is Science Today. In August of 2002 two massive deep earthquakes, centered in the same underwater trench below the Fiji Islands in the Pacific, occurred seven minutes apart. Geologist Harry Green of the University of California, Riverside, says the observation that one earthquake, measuring 7.6 on the Richter Scale, caused another 7.7 quake nearby, may have major implications for understanding how earthquakes are initiated.

Green: The effects of the first earthquake 300 km away and 65 km deeper is really very, very small and that's what causes the great interest—because how could this very small effect, within seven minutes, produce an earthquake even larger than the one that triggered it?

Narrator: Green says this event may help us understand the physical mechanism that causes earthquakes, so that we can better predict damaging quakes in the future – even ones at more shallow depths.

Green: It gives us a new time element to combine with seismology that can give us insight as to how the earthquakes get started.

Narrator: For Science Today, I'm Larissa Branin.