The Poincare Conjecture, a famous mathematics problem which has been finally solved, was honored as the Breakthrough of the Year, according to a statement released Thursday by the U.S. journal Science and its publisher AAAS, the nonprofit society.
The journal has chosen top 10 breakthroughs from the numerous research advances of 2006.
The statement said that in 2006, researchers closed a major chapter in mathematics, reaching a consensus that the elusive Poincare Conjecture, which deals with abstract shapes in three- dimensional space, had finally been solved.
"So we salute this development as the Breakthrough of the Year, " it said.
The conjecture, proposed in 1904 by Henri Poincare, describes a test for showing that a space is equivalent to a "hypersphere," the three-dimensional surface of a four-dimensional ball.
A century later, researchers were still trying to prove the conjecture. In 2002, Russian mathematician Grigori Perelman posted on the Internet the first of three papers that outlined a proof of Poincare's conjecture. By 2006, three separate teams wrote papers that filled in key missing details of Perelman's proof, and there was little doubt among his colleagues that he had solved the famous problem.
Science also gave props to nine other of the year's most significant scientific accomplishments:
-- Pulling DNA out of Fossils: Using new techniques for decoding and analyzing DNA, researchers captured genetic information from Neanderthal and mammoth fossils.
-- Shrinking Ice Sheets: Researchers documented a disturbing trend this year. The Antarctic and Greenland ice sheets are losing ice, at an ever faster rate, to the oceans.
-- Fishy First Steps: The discovery of a fossil fish with sturdy, jointed fins made a big splash in 2006. The fish is the closest known kin to limbed vertebrates and provides a window into how life left the oceans and ventured onto terra firma.
-- The Science of Invisibility: Though it looks nothing like Harry Potter's magical cape, the invisibility "cloak" that scientists developed this year is the first rudimentary device for shielding objects from view. The device guides incoming microwaves in such a way that they produce neither a reflection nor a shadow.
-- Hope for Macular Degeneration Patients: Researchers who study the form of vision loss known as age-related macular degeneration showed that the drug ranibizumab improves vision in some patient and identifying several genes that influence a person's susceptibility to the disease.
-- How Biodiversity Happens: From beach mice, to fruit flies, to butterflies, a variety of animals helped scientists uncover genetic changes that lead to the evolution of a new species.
-- New Frontiers in Microscopy: This year, biologists used new microscopy techniques that enabled them to see details smaller than about 200 nanometers, giving them a clearer view of the fine structure of cells and proteins.
-- Making Memories: Several discoveries in 2006 brought neuroscientists closer to understanding how the brain records new memories. The so-called "long-term potentiation" process that strengthens connections between neurons now seems even more likely to be the basis for remembering.
-- New Class of Small RNAs: Scientists discovered a new class of small RNA molecules that shut down gene expression, called " Piwi-interacting RNAs."
In the meantime, Science's predictions for hot fields and topics in the upcoming year include whole-genome association studies, optical lattices, the search for Earthlike planets around other stars, and comparisons of primate genomes.
Science also selected the Breakdown of the Year: The extent of the fraud committed by stem cell researcher Woo Suk Hwang and his colleagues, who published two key papers in Science, came to light in 2006, as did several other incidents.