MUSIC: "Our World" theme
Straight ahead on "Our World" ... The space shuttle ends one of its toughest missions yet ... a few extra kilos may help you avoid disease ... and how geographic information systems make a difference ...
PHOENIX: "You start to be able to do some analysis and say, OK, where are the people who are at the most risk? How do we get relief supplies to them?"
Computers plus maps equals GIS ... Our nursing shortage may affect your health care, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
On Wednesday, the Space Shuttle Discovery slipped out of orbit and returned home as Commander Pam Melroy brought the spacecraft to a picture-perfect landing under the blue Florida sky.
NASA: "Discovery's rolling out on runway 33 at the Kennedy Space Center, wrapping up a 6.25 million mile [10 million km.] mission. Discovery completing its 34th mission to space and the 23rd shuttle flight to the International Space Station.
Discovery's 15-day mission focused on space station construction, and it was by all accounts one of the most challenging in the history of the shuttle program.
The shuttle delivered the European-made Harmony module to the space station, and relocated a structural element called the P-6 truss. That much was planned. But what NASA hadn't planned on was that a solar panel attached to that truss would tear as it was being unfurled.
Engineers on the ground cobbled together a repair plan using wire cutters, pliers and some homemade tools. Astronaut Scott Parazynski worked at the end of an extended robot arm, risking electric shock in the process as he, in effect, sewed together the torn pieces of the solar panel.
The next shuttle flight, named STS-122, is scheduled to launch on December 6. Shuttle Atlantis will bring a seven-member crew to the space station for more construction work, including delivery of the European Space Agency's Columbus Laboratory.
More space news, now, but a bit farther out in the universe. Actually a lot farther: 41 light years away.
Astronomers on Tuesday announced the discovery of another planet orbiting a distant star, making it the most crowded planetary system outside our own.
More than 260 planets have been identified beyond our solar system. The most recently discovered exoplanet, as they're called, orbits a star in the constellation Cancer.
One of the authors of a new paper announcing the discovery, Geoff Marcy of the University of California, says astronomers had already identified four planets orbiting this star.
MARCY: "We've been observing a Sun-like star called 55 Cancri, it's star 55 in the constellation Cancer, for 19 years, and we watch the wobble of this star as it's yanked on by the planets orbiting it. And we're just now announcing the discovery of the fifth planet, the first planetary system with five full planets orbiting a Sun-like star."
It's smaller than our eight-planet solar system ? so far, anyway.
Astronomers estimate the newly-found planet is about 45 times more massive than Earth and has a year of 160 Earth days. Lead author Debra Fischer says the planet may resemble Saturn in some ways.
FISCHER: "This planet we think is likely to have a fairly substantial atmosphere. It's very massive. It might not be the sort of place that, at least life as we know it, would find to be a comfortable environment. However, this planet, in fact, orbits in what we call the habitable zone."
The habitable zone of a solar system has a temperature range that might support life, if not on the planet itself, then possibly on a moon, if the planet has any moons; they don't know that yet.
Exoplanets are generally discovered indirectly by detecting changes in the light coming from a star as its orbit is affected by nearby planets. It's another instance of the doppler effect, as when a train whistle changes in pitch as it passes by you. Astronomers use the same principle but in a different set of frequencies. Sometimes it can take years to sort out these doppler observations.
Debra Fischer, of San Francisco State University, says the growing sophistication of the technique increases the chances of finding planets more like our own.
FISCHER: "So what we're doing right now with our observational technique, the Doppler technique, is taking really the very first steps to finding Earth-like planets. We're going to find, you know, we'll basically give NASA the addresses, the names and addresses, of the most likely candidates for Earth-like planets."
Debra Fischer and her colleagues will publish their findings in an upcoming edition of Astrophysical Journal.