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This week on "Our World" ... smallpox protection from long-ago vaccinations ... the current state of electric cars ... and unraveling the secret of long-distance animal migration...

LOHMANN:  "It just seems impossible that they're able to enter the sea and all by themselves swim around the Atlantic Ocean and then eventually come back to the place where they started out."

Those stories and more, including some words of wisdom from this year's Nobel laureates.

I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

NASA Delays Next Mars Mission Until 2011

NASA says next year's scheduled Mars mission will be delayed two years because of some stubborn technical issues, including problems with a motor on a next-generation rover.

The Mars Science Laboratory is designed to see if Mars might now - or in the past - have conditions favorable for life.

NASA Administrator Michael Griffin broke the news to reporters in Washington.

GRIFFIN:  "Despite the delay, work on the mission really is progressing well, with the exception of the motor problem, which we just do not yet adequately understand. But we've determined that trying for '09 would require us to assume too much risk, more than, I think, is appropriate for a flagship mission like Mars Science Laboratory."

The NASA chief said that the problems could probably be resolved in a few months, but because of the relative orbits of Earth and Mars, the next favorable launch date won't be until 2011.

The two-year delay will add $400 million to the cost of the mission, bringing it to around $2 billion.

Smallpox Vaccine Effective for Decades

Although smallpox was eradicated in 1977, health officials remain worried that smallpox could be used as a biological weapon. Smallpox vaccinations were halted decades ago, but a new study reports that, should the virus re-emerge, those who had previously been vaccinated should still retain much of their immunity. VOA's Rosanne Skirble reports.
SKIRBLE:  Researchers analyzed 50 years of blood chemistry data from 246 participants in the on-going Baltimore Longitudinal Study on Aging.

TAUB:  "And what's really unique about this study is we are not looking at one blood point, like bringing them in and drawing blood. We have blood banked for 50 years where we are able to look at two, four, six, eight different time points for an individual over time to see how, if their immune response has changed at all over time."  

SKIRBLE:  That's Dennis Taub, acting chief of the laboratory of immunology at the National Institute on Aging. He is lead author of the report, published in the December issue of the American Journal of Medicine.

TAUB:  "What we found was that 97 percent of the participants actually retain their immunity and that means that they actually retained a level of antibody that was measurable and based on the literature would be deemed to be protective."

SKIRBLE:  Taub says the long-term immunity surprised him.

TAUB:  "And that's without any re-exposure, natural exposure to the vaccine or to smallpox. That means the immune system has an incredible ability to retain that memory and to continue producing things over an extended time periods."

SKIRBLE:  Immunity remained high without booster shots, even for those participants in their 80s and 90s. Taub says the findings can help public officials better distribute vaccines in the event of an attack.

TAUB:  "If you have limited supplies they might be more usefully applied to people who have never been exposed than those who have been vaccinated."

SKIRBLE:  The supplies would be targeted at people born after 1972, when vaccination against smallpox was terminated. I'm Rosanne Skirble.

Batteries, Power Grid Seen as Electric Car Challenges

The U.S. state of Hawaii this week signed on to a plan to establish a network of electric-car recharging facilities. The plan is spearheaded by a company called Better Place, which has raised $200 million in private financing.

The company's idea is to develop a network of recharging stations, and provide charging services and the cars themselves for a monthly subscription fee that they say will be equivalent to the monthly cost of gasoline.

Better Place has already announced arrangements with Israel, Denmark, and the carmaker Renault-Nissan.

Major auto companies worldwide see electric cars in their future, and a lot of motorists are driving them today, mostly in the form of gas-electric hybrids.

The industry's U.S. trade group met in Washington this week to focus on some of the technical and policy challenges they face.

Most vehicles today store their fuel in a metal tank. Electric cars store theirs in a battery. Battery technology has been improving rapidly, but Nancy Giola of Ford says it's still a major roadblock.

GIOLA:  "The biggest challenge, and we've heard this repeatedly, remains the battery. Questions remain about the durability in real world use, safety, and of course affordability in the cost equation."

General Motors has been touting the Chevy Volt, a plug-in electric car that is due out in 2010. GM official Tony Posawatz said if they sell around 200,000 a year, they will be the world's largest buyer of lithium-ion batteries.

POSAWATZ:  "When someone asks me, where do I get these cells from, today the only choice I have is to go overseas and look at Asia."

Posawatz says importing the batteries adds several hundred dollars to the price of each car. It's also a security issue: some analysts worry about cars dependent on foreign batteries almost as much as they worry about cars dependent on foreign oil.

The U.S. electric power industry is excited about the prospect of fueling the next generation of cars and trucks. Thomas Kuhn of the industry's trade group, the Edison Electric Institute, says people will be able to refuel right at home.

KUHN:  "We can wire up in houses easily where there are garages, and where there are not garages, we can rev up in parking lots. So there is going to be an electric infrastructure need, and we think we can move that [forward] very, very quickly because electricity, fortunately, is everywhere."

Critics note, however, that many urban dwellers, for example, park on the street, not in a garage. Environmentalists worry that the increased demand for electricity will just mean more coal burned in power plants. Coal supplies half of U.S. electricity now, and renewable resources like wind and solar are strongest in areas that don't have a robust grid to get the power to consumers.

Senator Brian Dorgan from North Dakota, a state with great energy-producing potential, said building a 21st century transmission grid to get renewable energy to market is like the high-speed Interstate highways that began criss-crossing America in the 1950s.

DORGAN:  "We need to build a transmission superhighway in this country. And we need it because you can't produce wind from Texas to North Dakota and solar across the Southwest and other forms of energy where it exists in the renewable form of energy unless you have some place to put it on a wire and move it where it's needed. So if we're going to produce more, and we certainly have the capability, we need the transmission ability to move it."

Democratic Senator Byron Dorgan of North Dakota.

The internal combustion engine has dominated motor vehicles for a century, but it wasn't always like this. At the beginning of the automobile era, gasoline-powered cars competed with electricity and steam, and Ed Cohen of Honda says the future may look like that, too.

COHEN:  "Every one of these technologies - hydrogen, natural gas, battery electric, gasoline; you can improve the internal combustion engine and make tremendous strides in that regard. They're all going to be a part of this mix. And each technology is going to appeal to a different type of consumer."

If you've got any thoughts on electric cars, let us know. Our email is, or listen for our postal address at the end of the show.

Nobel Laureates Cite Importance of Educating Youngsters

In a few days, this year's Nobel Prize winners will gather in Stockholm, Sweden -- and Oslo, Norway, in the case of the Peace Prize -- to accept their awards.

Before traveling to the ceremonies, some of the American laureates were in Washington for a symposium that has become an annual tradition at the Swedish embassy here.

Economics laureate Paul Krugman of Princeton University and the New York Times talked about the economic downturn and how the nation can recover without making matters worse.

Chemistry prize winners Roger Tsien and Martin Chalfie discussed their prize-winning work on green fluorescent protein. We talked about that back in October here on Our World, when the awards were announced.

During the formal presentation there was some discussion of science education, which is so good at the top American universities and by most accounts dismal in too many of America's elementary and secondary schools. I asked Dr. Chalfie if he had any suggestions that he might like to pass along to the incoming Obama administration.

CHALFIE:  "One is, we need more and better trained teachers. That seems to be very important. I think we also need to look at the science curriculum and revamp it from the point of view, as I mentioned before, of not looking just at what facts can we give out, but how can we actually inculcate the excitement about doing the experiments, thinking about things, discovering aspects of our world. And I think that emphasis should increase in terms of education. I'd certainly like to see that."

Chalfie's co-laureate in Chemistry, Roger Tsien, said he worries that government initiatives that require passing scores on standardized tests tend to dampen student creativity.

TSIEN:  "Whenever I took science courses myself that were focused on being able to pass tests, that's when I personally lost interest. And I only got interested in things when I could figure it out for myself. Now people will say I'm not exactly a good representative of the rest, but I suspect with that bit of motivation, I may not have been so different."

Roger Tsien at the Swedish embassy here in Washington. He and the other Nobel laureates will receive their awards on Wednesday, December 10.

Electronic Reference Books on our Website of the Week

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

This week, it's a free online library with an emphasis on the top names in reference books, and more.

van LEEUWEN:  " is a website that allows the intellectually curious to find a full suite of English language reference works - encyclopedia, dictionary, usage guides, quotation database - to get the answers that they might be looking for."

Steven van Leeuwen is the head of, where the reference shelf includes the Columbia Encyclopedia, the American Heritage Dictionary, Roget's Thesaurus, and many other high-quality reference works.

One-third of Bartleby's users come from outside the United States, so you'll be in good company if you want to brush up on your English skills with classics like The Elements of Style and H.L. Mencken's The American Language.

van LEEUWEN:  "Well, English usage is one of our most-used categories. We find that a large percentage of our users are people who do writing as part of their daily jobs, they're information workers. And they come to Bartleby for authoritative answers to their English usage questions."

Bartleby also features a small number of classic novels and some 18,000 poems for your reading pleasure. In fact, Walt Whitman's Leaves of Grass was Bartleby's very first book, published online in 1994.

Bartleby is fully searchable, and browsable, too, and it's understandable why students find it a great resource.

van LEEUWEN:  "Almost half of our usage is in schools. And so now, at the peak of the fall semester, we're seeing the largest usage, which would be upward of a half a million people a day."

Join them for high quality reference books, novels, poems, quotations and more at, or get the link to this and more than 200 other Websites of the Week, from our site,

MUSIC:  The John Tesh Project - "Book Of Days"

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

Giant Tortoise Gets Help in Reproducing

British naturalist Charles Darwin visited the Galapagos Islands in 1835 and described the giant tortoise as being so big that it required up to eight men to lift one up.

In the 19th century, the tortoises flourished there, but today conservationists say there's but one surviving giant tortoise. His name is Lonesome George, and as we hear from VOA's Paul Sisco, a team of scientists is trying to make Lonesome George a father.

SISCO:  Since Lonesome George was discovered in 1972, scientists at the reproduction center for giant tortoises at Galapagos National Park have played matchmaker. The last surviving Galapagos giant tortoise on the planet has been paired with countless females of related subspecies. But until recently, George has shown no interest in the opposite sex.

To the surprise of researchers, however, two females paired with George laid a batch of eggs between July and September.

Park scientist Godfrey Merlen:  

MERLEN:  "After 36 years of no reproductive effort whatsoever in an enormous effort by human beings to make him reproduce, George by himself has produced, through two females, a total of eleven eggs which are now in an incubator."

SISCO:  Several more eggs were eventually uncovered. Park rangers carefully weighed, cared for and cataloged their growth in incubation. It takes more than 100 days for these tortoise eggs to hatch.  

Alas, in November, bad news was reported at a one-of-a-kind news conference in Galapagos National Park.

MERLEN:   "The eggs produced by females living with Lonesome George are not doing very well. It seems that a number of them are losing too much weight during the development process and that others are growing funguses on the outside of the eggs. It appears that at the moment, most of these eggs will not produce live young."

SISCO:  Some of his eggs are misshapen. Many lost between 35 and 50 percent of their weight in the weeks following initial incubation.

Scientists say George, between 80 and 100 years old, is at his sexual peak. So if he is not infertile, he could become a middle aged parent in the months and years to come.

While George seems indifferent to fatherhood, scientists are holding out hope for him and the species. A park official says there's a slim chance the remaining eggs could hatch before the end of December.

Paul Sisco, VOA News.

New Theory Explains Great Feats of Animal Navigation

And finally ... If you're traveling in an unfamiliar area, you might want to have a map, maybe a compass. Perhaps you'll ask directions along the way. But what about migratory birds, fish, and other animals who navigate thousands of kilometers, traveling to places they've never been to, and somehow ending up in the right place.

In the case of some animals like salmon and sea turtles, the right place is where they were born, where they know - somehow - that conditions are right for their newborns to start life, too.

Professor Kenneth Lohmann has been studying the remarkable navigational skills of the animal kingdom, and he's just published a new paper that prompted our interest. We reached him at the University of North Carolina, where he is a professor of biology.

LOHMANN  Animal navigation turns out to be remarkably complex. All animals that have been studied so far use more than one type of information. And in some cases, animals may draw upon six or even eight or more different types of information in the environment and use those interchangeably.

Q:  For example?

LOHMANN:   Well, one of the best studied examples would be homing pigeons. Under certain circumstances they seem to use visual landmarks; in others they use sun compasses or the earth's magnetic field or their sense of smell, as well as possibly such things as infrasound - very low frequency sound that we ourselves are not able to hear.

Q:  You and your colleagues have been studying sea turtles and their navigational skills for some time now. What have you learned up 'til now?

LOHMANN:  We've learned a great deal about the way that young turtles guide themselves, steering their first migration across the Atlantic Ocean. The turtles that we study leave the east coast of Florida, swim offshore, and then enter a circular current system known as the North Atlantic Gyre. And one of the most remarkable discoveries that we made with the young turtles is that they have the ability to distinguish among different magnetic fields that exist at different locations along their migratory route.

Q:   Let's talk about your paper this week in the Proceedings of the National Academy of Sciences. What exactly are you reporting?

LOHMANN:  In the new study, what we've proposed is a new theory to explain how sea turtles and salmon are able to guide themselves across enormous expanses of ocean and return to the same area where they themselves began life. The idea that we propose is based on two findings.

The first of these is that sea turtles and salmon are both able to sense the earth's magnetic field.

The second finding is that it turns out that different areas of coastline have associated with them slightly different magnetic fields.

And so in the new study, what we've done is put these two ideas together, and what we're proposing is that salmon and sea turtles, at the beginning of their lives, learn or imprint on the magnetic field of their home area, and then retain this information as they migrate out far away across thousands of kilometers of ocean, and finally, when it's time for them to return, they can exploit this information to help guide themselves back into the correct part of the world.
This particular study is theoretical in nature. The idea has not yet been proven. We're very excited about it because this is the first plausible explanation that has been put forth that can account for how sea turtles and salmon can find their way back, and so we think it's likely to be true, but the fact remains that it's not yet been shown to be correct, and only time will tell whether it is.

Q:  How do the animals do this, actually, sense the magnetic field? Humans, in a conscious way, are not aware of the magnetic surroundings in which we all live. How do the animals do it?

LOHMANN:  There are two main ideas that are under consideration. One of them is that little particles of the mineral magnetite might provide the physical basis for the magnetic sense. Magnetite is a magnetic mineral. And the idea is that there may be little particles of magnetite in the brains of sea turtles and birds and a number of other animals that can sense magnetic fields, and these little crystals may in fact rotate into alignment with the field in the same way that a compass needle rotates into alignment.

The other idea is that there are some very unusual chemical reactions that may occur in the process of vision. So as an animal looks out at the world, it would see more or less everything that we see, but superimposed on that it would see a pattern of small lights or colors, as it faces, for example, toward the north. So animals, in effect, could see the magnetic field or at least see a distinctive visual pattern when they face in different directions.

Q:  I know you study this in a rigorous scientific way, but do you step back sometimes and think, boy, this is amazing!

LOHMANN:   I consider these migrations to be among the most remarkable phenomena in existence. I've been fascinated for a number of years in the sea turtle migrations in particular, and when you look at these young turtles coming out of the nest, never having been in the ocean before, it just seems impossible that they're able to enter the sea and all by themselves swim around the Atlantic Ocean and then eventually come back to the place where they started out. So it certainly does fill me with a sense of wonder.

If you're curious and want to learn more, there are some great explanations of all this on Professor Lohmann's website. We'll have a link for you on our site,

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

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Rob Sivak edited the show. Bob Doughty is the technical director.

And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.