Accessibility links

Our World — 24 May 2008


MUSIC: "Our World" theme

This week on "Our World" ... An astronomical jackpot: the first glimpse of a dying star ... why growing up dirty may help avoid allergies ... and how high tech industries are helping kids get interested in science ...

MCKINNEY: "The science of physics is projectiles. The science of chemistry is blowing things up. And if you study these long enough, you get to combine them, and that's pretty cool. And someone's going to pay you to do that."

Those stories, the straight poop on how primates help keep forests healthy, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Scientists this week reported observing the very beginning of one of the most spectacular shows in the universe — a supernova, the gigantic explosion that marks the death of a massive star.

For astronomers, seeing a supernova isn't all that unusual. What was extraordinary in this case is that they were able to watch the entire event unfold thanks to a spectacular bit of good luck for a young researcher at Princeton University named Alicia Soderberg.

SODERBERG: "On January 9 of this year, I truly won the astronomy lottery. While studying a supernova in a galaxy 100 million light years away, a star in the galaxy exploded right before my eyes. This was the birth of a new supernova, caught on tape for the very first time."

Soderberg was observing a supernova called 2007uy using a NASA astronomy satellite called Swift. Unlike the more famous Hubble space telescope, which is basically an optical telescope, Swift looks out into space on different wavelengths, including X-rays.

While pointed at supernova 2007uy, Swift detected a burst of X-rays signaling the beginning of another supernova elsewhere in that galaxy.

The X-ray burst at the beginning of a supernova had been predicted, but had never been seen before. It lasted just five minutes, and it prompted a quick response from Soderberg.

SODERBERG: "When I saw the images coming off the satellite, I knew immediately that this was an extraordinary event. I had two very important tasks to do. First I had to alert the astronomical community. And second, I had to steer as many telescopes in the direction of this outburst as fast as I could. Within a day or two of this X-ray outburst, the largest telescopes in the world were trained on this object."

As a result of Soderberg's quick reaction, astronomers captured a valuable set of observations in different parts of the electromagnetic spectrum, which will help them better understand supernovas. Her paper was published this week in the journal Nature.

Soderberg says the burst of X-rays from a dying star will not only help astronomers learn more about the lifecycle of stars, but also provide early warning of an impending supernova.

Harvard University astronomy professor and supernova expert Robert Kirshner says the serendipitous discovery of Soderberg's supernova, known as 2008D, need not be a one-of-a-kind event.

KIRSHNER: "If we build the right type of X-ray satellite that could monitor the whole sky for events like this, then 2008D won't be the last one that's found from its X-ray emission. We would be able to see them even if we were kind of lazy and as a matter of routine. Which would be great."

By the way, if you're worried about our Sun, you can relax. Experts say there is about one supernova per century in any one galaxy, and in any event a supernova requires the mass of a really big star and our Sun just doesn't qualify.

The supernova Alicia Soderberg spotted was 88 million light years away. Closer to home — but still in space — the Mars Phoenix Lander spacecraft is on its final approach to the Red Planet, where — if all goes well — it will touch down late Sunday night UTC and soon begin digging beneath the surface looking for signs of water and other evidence that life might have once existed on Mars.

A safe landing is by no means a sure thing. In 1999, a nearly identical spacecraft, called the Mars Polar Lander, apparently crashed on the Martian surface.

The most recent successful landings on the planet were the Mars rovers, Spirit and Opportunity. They each came down hard, their landings cushioned by air bags. Phoenix, however, is too heavy for that, so it will be landed the old-fashioned way, with its descent first slowed by a parachute, and then by retro-rockets.

NASA official Ed Weiler admits the track record for Mars landings is not great.

WEILER: "Fifty-five percent of all human attempts to land robots on Mars have failed. The U.S. has a better record, as we have succeeded in five of six attempts. But three of those five successes employed air bags. Viking was the last time we successfully used retro-propulsion and landing legs, so it has been over 32 years since NASA has been successful in such a landing."

Scientists working on the Phoenix project think the $420 million mission is worth the risk. Doug McCuistion [Mc-KWISS-ton] heads NASA's Mars Exploration Program. He says this mission is all about the water.

McCUISTION: "It's the first lander to the Martian arctic. And it's also the first mission that's actually going to touch the water. The program's mantra has been 'follow the water.' This time Phoenix actually is going to touch it for the first time."

Water, of course, is an essential component of life as we know it. It would also come in handy whenever humans visit the Red Planet.

The seven-year-old Mars Odyssey satellite, which is in orbit around Mars, has identified water under the planet's surface. Phoenix principal investigator Peter Smith of the University of Arizona says it's mostly frozen water — ice — mixed in with the soil at higher latitudes — which is where Phoenix is landing.

SMITH: "And so we expect a tremendous abundance of ice in these northern plains, and in fact our landing site is in the highest concentration of ice outside the permanent polar caps.

The landing site is at 68 degrees north latitude — comparable on the Earth to northern Sweden, only a LOT colder.

Phoenix is scheduled to spend at least three months digging up bits of Martian soil with its two meter-long scoop and studying them with on-board science instruments. Samples will be vaporized and analyzed with a mass spectrometer. A pair of microscopes will beam detailed images back to Earth, where scientists will see if structures in the rock provide evidence of liquid water in the Martian past. There's also a compact weather station to track changes in temperature, pressure, and blowing dust and ice particles.

Unlike the twin Mars rovers, which have ranged over many kilometers of the Martian landscape, Phoenix will remain in one place. The Phoenix scientists are interested in knowing whether Mars — or at least this region of the planet — has some of the raw materials of life.

SMITH: "Our highest goal is to see if this creates a habitable zone on Mars, where we might find organic materials. We might find the presence, at least periodically, of liquid water, and we might find chemical energy sources."

In the first hours of Monday morning UTC, engineers at NASA's Jet Propulsion Laboratory in California should get radio transmissions from Mars — which take about 15 minutes to travel to Earth — telling them if the Phoenix spacecraft landed safely.

Doctors have noticed that as people become more urbanized, they're also more likely to suffer from allergies. Researchers have proposed an explanation called the 'hygiene hypothesis.' It's the idea that being exposed to dirt and bacteria when young actually protects people from developing allergies. As we hear from health reporter Rose Hoban, a new study supports that idea.

HOBAN: Bianca Schaub is a pediatrician at the University Children's Hospital in Munich, Germany. She says she knew that children who are born into farm families have lower rates of asthma and allergies, which is consistent with the hygiene hypothesis. She recruited two groups of children to test it out.

SCHAUB: "One group, where the mothers were exposed to the farms during the whole pregnancy, and the other group where the mothers were not exposed to farms. And we compared the immune regulation of these two groups of children."

HOBAN: Schaub actually started studying the children before they were born, when their mothers were pregnant. Then when the children were born, Schaub took samples of blood from the umbilical cord. She found changes in their blood right away.

SCHAUB: "These children had a specific type of immune response in the sense that they had higher regulatory T-cells. These are cells which keep the immune system healthy, so which keep it basically in control so that there is no modification, no disease happening. So it seems like this exposure contributes to a better regulatory T-cell function in early life."

HOBAN: Schaub says as these children grew up, they had fewer allergies and were less likely to get asthma. She says the effect was greatest for children of women who worked closely with animals.

SCHAUB: "We know when they are, for example, exposed to different species of animals, that this is protective. So it seems like the different species represent a variety of stimuli for the immune system which seem to be good in terms of preventing these allergic immune responses."

HOBAN: Schaub says early exposure to allergens is a little like getting a vaccination when you're young. She says in the future, information from her research might be used to create a vaccine against allergies for children who don't grow up on farms - but she says that's still in the future.

Schaub presented her research at the American Thoracic Society's annual meeting in San Diego, California. I'm Rose Hoban.

Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

This week it's the site of the U.S. National Cancer Institute, with an easy-to-remember address, cancer.gov.

It's an authoritative place to learn about the many forms of cancer, and while the information is presented for patients and the general public, there is also detailed technical information for physicians and other specialists.

Now, there are a lot of online sources of medical information, but cancer.gov comes directly from one of the world's premier research institutions, and the information is constantly updated.

MANROW: "We employ rigorous quality assurance in terms of making sure the content is as current and as accurate as it possibly can be. A lot of websites, they'll put information up, but if you look at it over time you'll see that it's not being updated frequently. We have the capability of updating information on our website on a daily basis."

Richard Manrow helps oversee the cancer.gov website, which is a virtual encyclopedia of information on all forms of malignancy — brain tumors, prostate cancer, leukemia, and others. There's also help if you want to reduce your risk of cancer.

MANROW: "In many cases there are factors that contribute to the development of cancer that are beyond our control, but there are things that can be done to prevent certain types of cancer. Certainly the biggest preventable cause of cancer relates to smoking. So we have a lot of information and resources about tobacco cessation."

Among the site's many other features are a dictionary of cancer terms and a database of clinical trials, where promising cancer treatments are tried out on volunteer patients.

MANROW: "We go to great efforts and work with organizations around the world to identify the latest cancer clinical trials that are being conducted, and to provide easy to understand descriptions of those trials for both health professionals and for patients on the website."

The site also includes statistics about cancer, and maybe more importantly, a guide to understanding those statistics. And much of the information is available in Spanish as well as English.

Authoritative cancer information at our Website of the Week, cancer.gov, or get the link from our site, voanews.com/ourworld.

MUSIC: Michael Jerome Brown - "Cancer Ward Blues"

You're tuned to VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.

Schools around the United States are trying to interest students in science and engineering, and are getting help from the aerospace and high tech industries. Project Lead the Way, which uses industry-designed curricula, is now offered in over 1,300 schools across the United States. Mike O'Sullivan, tells us how the program is exciting students in one California desert community.

O'SULLIVAN: Antelope Valley, on the western edge of the Mojave desert, is home to Edwards Air Force base, where the space shuttle sometimes lands and where the experimental X-15 aircraft set many speed and altitude records. The region has facilities of the aerospace companies Boeing and Northrop Grumman, and Lockheed Martin develops and assembles advanced and secret aircraft. Nearby, at the new Mojave spaceport, aerospace entrepreneur Burt Rutan launched the first private manned spaceflight in 2004.

The Valley is also home to new housing developments and a growing population of school-age youngsters. And local schools are working with the aerospace companies to get students interested in careers in the field.

Randy Scott, a retired Air Force engineer, says the industry provides curricula and other support.

SCOTT: "It's not necessarily monetary support. It might be in terms of mentors. It might be in terms of helping out after school, whatever it might be, from the standpoint of that's the future workforce. In addition to the fact that they're dealing with the sons and daughters of the current workforce which need to be supported also."

O'SULLIVAN: In the desert city of Palmdale, 3,300 students attend Pete Knight High School, named after the test pilot who holds the world speed record for a winged, powered aircraft. Ken McKinney, a systems engineer with Lockheed Martin, helps out in the classroom and tells students why science and mathematics are interesting.

MCKINNEY: "When you apply math, it's pretty fun. It's the language of the universe. And science is really fun. The science of physics is projectiles. The science of chemistry is blowing things up. And if you study these long enough, you get to combine them, and that's pretty cool. And someone's going to pay you to do that. That's the kind of the journey we go on."

O'SULLIVAN: Students are responding. Freshman Angela Ortega hopes to become a structural engineer.

ORTEGA: "Well, I've been interested in math and science for, like, ever. They're like my favorite subjects. so engineering sounded like a good option."

O'SULLIVAN: The school's principal, Susan McDougal, grew up in this desert region after her father came here to work on the X-15. She says the area is rich with career opportunities, and teachers are trying to keep options open for the students.

McDOUGAL: "And part of that is keeping them engaged in school. So programs like Project Lead the Way keep our students engaged in school, keep them focused on their studies, so that they have a goal when they leave here."

This high school has two rocket teams, which have competed in national competitions in each of the past two years.

Senior student Jose Ochoa says that designing rockets got him away from the television and into science.

OCHOA: "And rocket club in general sparked that because I had to go home and instead of watching TV, you had to learn how to derive equations and how to use software to create these rockets."

O'SULLIVAN: Ellen Bendell of Lockheed Martin says Project Lead the Way is a kind of community service for both her company and the engineers who help out with the program. She says it also serves the interests of the aerospace industry, which faces a shortage of engineers and technical workers.

BENDELL: "The objective is to create a pipeline in the schools that will help feed from elementary school into the middle school into the high school, through the junior college and into the universities, and then hopefully, of course, to recruit those people that we are going to be needing."

O'SULLIVAN: To fuel that pipeline, schools in Antelope Valley offer special classes in robotics, architectural engineering and other technical fields. At Pete Knight High, the focus is on rockets, and teacher Bill Lewis says his students get a first-hand view of the aerospace industry.

LEWIS: "Students were able to take a tour of the local Lockheed facility, and last year the students said that was the best field trip they had ever been on, and they really, really enjoyed it. Some of them have decided now that aerospace engineering is really what they want to follow."

O'SULLIVAN: He says some other students decide that engineering is not for them, but their exposure to the field gets them thinking about other technology careers. Mike O'Sullivan, VOA News, Los Angeles.

Monkeys and apes play a crucial role in dispersing the seeds of fruit trees in tropical forests. But across the tropics, habitat loss and hunting are decimating local primate populations, and may be putting many tree species at risk. Véronique LaCapra reports.

LaCAPRA: How a plant spreads its seeds — and how far — are key to its survival. Some species rely on wind or water to disperse their seeds, but for trees in the tropics, animals often play a critical role.

STONER: "Primates in particular are one of the most important mammals or large vertebrates that disperse seeds in tropical forest."

LaCAPRA: Kathryn Stoner is a research ecologist at the National University of Mexico. She has been studying how certain monkeys contribute to seed dispersal in a tropical forest in the southern Mexican state of Chiapas.

STONER: "They'll eat a fruit, then they move, they can move up to kilometers sometimes, seven or eight hours later before they actually defecate the seed and the seed may fall down someplace where it will germinate and grow up to be an adult tree."

LaCAPRA: Stoner notes that some species of primates may actually help degraded areas of forest to re-grow, by dispersing seeds as they move between forest fragments.

The role of primates as seed dispersers has been observed throughout the tropics: in Latin America, in Asia and in Africa.

For the past 17 years, anthropologist Joanna Lambert has been studying seed dispersal in Uganda's Kibale National Park, which is known for its unusual abundance of primates. In a presentation sponsored by the National Science Foundation, she described the results of her research.

LAMBERT: "What I've found is that depending on the species of tree and the fruit that's being consumed, primates are responsible for 78-92 percent of the removal of the seeds, relative to the major fruit-eating birds. On average the monkeys and chimpanzees of Kibale move 34,000 seeds in a square kilometer in a day."

LaCAPRA: And many of those seeds grow into trees used by local people for fruit or for medicinal purposes.

LAMBERT: "I have found that 42 percent of the species, the fruit species that primates very effectively disperse in Kibale have resources that are used by people."

LaCAPRA: But according to the International Union for Conservation of Nature, close to one third of the world's primate species are in danger of extinction.

In Asia and Latin America, tropical forest clearing for human settlement, agriculture, and commercial logging are destroying primate habitat.

Hunting is also taking a huge toll on primate populations, as logging operations open up new roads through previously inaccessible areas of forest, and rural subsistence hunters exchange their traditional weapons — bows and arrows, wooden traps, and blowpipes — for guns.

In Western and Central Africa, hunting is largely being driven by demand from urban markets. Known as "the bushmeat trade," the commercial hunting of primates and other wild game species has eliminated all the large mammals from some areas of forest.

LAMBERT: "The direct sort of consequences of this are relatively obvious. The direct consequences of a bushmeat trade or a bushmeat crisis are the loss of species, the loss of actual animals in a forest."

LaCAPRA: But, Lambert explains, for people with no other way to earn a living, bushmeat hunting may seem like their only option.

Both she and Kathryn Stoner emphasize that hunting and habitat loss will affect more than just primate populations.

STONER: "We're actually in the very beginning stages of what we may see as a very large change in composition and structure of tropical forests, as a consequence of elimination or reduction of primate populations."

LaCAPRA: The process may be already underway.

As primate populations decline, preliminary studies have found effects in tree seedlings, including a different mix of species and less genetic diversity. I'm Véronique LaCapra.

MUSIC: "Our World" theme

That's our show for this week. If you'd like to get in touch, email us at ourworld@voanews.com. Or use the postal address —

Our World
Voice of America
Washington, DC 20237 USA

Rob Sivak edited the show. Eva Nenicka is the technical director. And this is Art Chimes, inviting you to join us.

XS
SM
MD
LG