NASA Satellite Finds Massive New Antarctic Iceberg
New NASA satellite pictures released on Tuesday shows crevasses and other surface fractures forming in a recently discovered crack in the Antarctic ice.
Thanks to the Multi-angle Imaging SpectroRadiometer (MISR), scientists can get a view from nine angles, revealing subtle nuances of terrestrial features like the 15-mile (25-kilometer) fissure in the Pine Island Glacier.
The rapidly spreading crack was discovered last week by the Landsat 7 satellite as it examined hidden continental features that shape the future of the world's largest ice sheets, the National Aeronautics and Space Administration (NASA) said.
Glacier expert Robert Bindschadler of NASA's Goddard Space Flight Center in Greenbelt, Maryland said that the crack first was detected on Jan. 16 during his daily review of new Landsat 7 images of Antarctica. The thin crack extended more than two-thirds of the way across the glacier, he said. There was no crack in a previous image 10 months earlier.
"Most of this crack formed very rapidly, in less than five weeks,'' Bindschadler said in a statement. "Right now it is growing much more slowly, at about 13 meters (40 feet) a day. My prediction is that the crack will result in the calving of a major iceberg in probably less than 18 months.''
Bindschadler contacted colleagues working with other Earth-observing sensors -- two instruments aboard NASA's Terra satellite, the Canadian Space Agency's Radarsat and the European Space Agency's radar imager -- to try to determine when the fracture had formed and how quickly it was growing, NASA said. The researchers managed to estimate the growth rate of the crack and when it had formed by comparing observations from different dates.
Landsat 7, a cooperative mission between NASA and the U.S. Geological Survey, last month finished its second annual continent-wide mapping of Antarctica. Because of a change in the spacecraft's observing schedule, this year's collection of images promises to provide a wealth of new surface features, NASA said. The new viewing angle altered the patterns of shadows on the uniform, white surface, revealing subtle differences in surface topography.
MISR, built and managed by the Jet Propulsion Laboratory, is one of several Earth-observing experiments aboard NASA's Terra satellite, launched in April 1999. With its capability to detect features as small as 50 feet (15 meters) across, Landsat 7 provides the most detailed observations available of the remote continent, many parts of which have never been mapped at such fine resolution before, the space agency said.
