1.  
2. Back
3. IMAGE 1 of 4
4. Next

POLAR YEAR: Until March 2009, the world's scientists will be undertaking a historic effort to chart the changes in the polar regions.
U.S. Fish and Wildlife Service

Today marks the beginning of the International Polar Year (IPY), a two-year mission to explore Earth's poles. Some 50,000 scientists, artists and other participants from 63 nations will undertake 460 projects—ranging from lacing the Antarctic ice with neutrino-spotting sensors to a survey of historic Inuit knowledge of Arctic sea ice—in a massive effort to enhance scientific understanding of the poles before they change. "The scientific community feels that we need an urgent and comprehensive look at the polar regions," says David Carlson, director of the IPY's international program office.

This IPY is the first such multinational comprehensive look at the polar regions since 1958, when the International Geophysical Year (IGY) wrapped up. "Fifty years ago, we were motivated by discovery and now we are motivated by change," Carlson says. "Then we got the first measurements of ice thickness in Antarctica. Now we think that may be changing. Then we got the first look at ocean circulation in the polar regions, now that is changing."

Building on a tradition launched in the 1870s by Austrian polar researcher Carl Weyprecht—who attempted to unite the competing nations of the time in the pursuit of fundamental polar insight—this IPY will last two years, despite its name, because of the harsh Arctic and Antarctic conditions. Experts says that it may be the last chance to study the polar regions as they are now; global warming is already being felt most severely in these areas and transforming them as a result.

Following are a few of the myriad IPY projects:

Build an IceCube to Catch a Neutrino

Neutrinos are among the building blocks of matter. But because they lack a charge—hence the name—and have little mass, they are extremely difficult to detect. One of the ways to find the neutral particles is to wait for the extremely rare occasions when they collide with intact atoms, producing a shower of charged particles. "When a charged particle moves through a very transparent medium, it fills it with a blue light," explains Francis Halzen, a particle physicist at the University of Wisconsin–Madison. "Because the particle goes faster than the light [in this medium], it forms a bow wave like a speedboat in water. From that bow wave, you can map the direction of the original particle."

Neutrinos, because they carry no charge, travel in a straight line from wherever they are produced as long as they have not had any previous collisions. Many are manufactured in our own atmosphere, others travel from the sun and still others origin may be from distant regions of space. "The popular sources that people predict are like supernova[e], neutrinos, active galaxies, gamma-ray bursts," Halzen says. "The atmosphere is totally uniform in terms of the neutrinos it produces. So you look for hot spots in the map."

To produce the map in the first place, though, requires an enormous transparent medium. Halzen and his collaborators hit upon the idea of using the ice under the South Pole as that medium. The project, dubbed IceCube, will sink 4,800 photomultipliers—sensors that detect light—into a billion tons of ice, reaching one mile (2.4 kilometers) below the Antarctic surface. Some 1,500 sensors are already in place, transmitting data via satellite to researchers in Madison, and the ice has turned out to be the best place for such a sensor. "This ice is made from snow that was incredibly clear and pure. It's 100,000-year-old snow that is compressed," Halzen says. "We have found layers in Antarctic ice, where the absorption is 300 meters, as clear as salt crystals you make in a lab." Of course, the ice also offers one more benefit: "We can walk on our experiment."

Mapping the Tundra and the Permafrost

The Arctic is changing, but nowhere is this less immediately visible than in the thawing permafrost. "You don't see it, like glaciers and snow and sea ice," says Jerry Brown, retired geocryologist and president of the International Permafrost Association. But thawing permafrost can have dramatic effects both visible and invisible, from collapsing roads and leaning trees in Alaska to freeing greenhouse gases that had been frozen for millennia.