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This week on Our World: A new satellite to monitor Earth's potentially climate-changing carbon emissions... testing new drugs in developing countries ... and engineering a water system upgrade for New York City...
CHRIS SMART: "This tunnel that we broke into is over 100 years old. We like the way it was built. I hope that within 100 years, the guys look at the work we've done, they say the same thing."
Those stories, a mental health Website of the Week, and more.
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Tuesday morning, U.S. time, the space agency NASA is scheduled to launch a satellite that will look down on earth to monitor sources of carbon dioxide as well as places called carbon sinks, where CO2 is absorbed. Carbon dioxide, of course, is one of the principal greenhouse gases widely believed to be responsible for global warming. Reporter Tom Banse says the Orbiting Carbon Observatory satellite is designed to help scientists get a handle on the ins and outs of the carbon cycle.
BANSE: Washington State University professor George Mount is on the trail of a mystery. Our cars and factories and all of us produce lots of carbon dioxide, a key culprit in global warming. But tracking it isn't easy.
MOUNT: "About half of the CO2 that is produced stays in the atmosphere."
BANSE: The other half disappears somewhere...
MOUNT: "A lot of it goes into the ocean. Obviously, a lot of it goes into plants."
BANSE: Places that absorb a lot of carbon dioxide are called "sinks."
MOUNT: "People are very interested scientifically and politically in where on the globe these sinks of carbon dioxide are."
BANSE: It's not hard to conclude that owning a carbon sink could be a valuable thing in a world worried about global warming. The difficult part is figuring out where the good sponges are. That's where George Mount comes in. The atmospheric scientist is part of an international team helping design and test NASA's first satellite to track carbon dioxide.
MOUNT: "The idea of the satellite was to make extremely accurate measurements of CO2 from space, where you can get global coverage of the CO2 concentration and can then start to quantify where it's coming from and where it's going."
BANSE: Mount says the Orbiting Carbon Observatory detects odorless, colorless CO2 indirectly from its vantage point 690 kilometers above the earth.
MOUNT: "CO2 is a copious absorber of infrared light. And the photons of light that travel from the sun go through the atmosphere once, hit the ground, reflect back up, go through the atmosphere again, and then up to the satellite sensor. So it'is possible to deduce the abundance of the molecule [by measuring the difference in the amount of infrared light]."
BANSE: George Mount says the timing of the upcoming launch couldn't be better. Lots of countries, states, even some county governments and corporations are trying to figure out how their carbon emissions and sinks balance.
The vast tracts of public and private forestland in the northwestern United States are an obvious sink. The giant timber and paper company Weyerhaeuser owns nearly one million hectares in the region. Spokesman Frank Mendizabel says the company finds it challenging to determine how much carbon dioxide its tree farms soak up.
MENDIZABEL: "It's a very difficult thing to measure and has a lot of technical details, I think, yet to be worked out."
BANSE: Data on greenhouse gas concentrations for any part of the planet should start to become available a few months after the Orbiting Carbon Observatory is launched.
For Our World, I'm Tom Banse in Pullman, Washington.
Vaccines have been one of the greatest public health achievements in history. Doctors have developed vaccines to prevent some of the world's most terrible diseases, including smallpox and polio. But one of the limitations of vaccines is that they need to be injected with a needle, and they often need more than one dose to be effective. As we hear from health reporter Rose Hoban, it would be much easier if all vaccines could be given by mouth.
HOBAN: Now scientists think that might be possible.
Microbiologist Todd Klaenhammer from North Carolina State University has spent his career studying the kinds of bacteria that we add to food, such as lactobacillus acidophilus.
KLAENHAMMER: "We eat this in yogurt and a lot of different products every day. So it's totally safe, you can eat these things at over 100 million per gram."