* Astronomy

A reclusive Russian won an academic prize Tuesday for work toward solving one of history's toughest math problems, the Poincare conjecture, but he refused to accept the award - a stunning renunciation of accolades from the top minds in his field.

Grigory Perelman, a 40-year-old native of St. Petersburg, was praised for work in the field known as topology, which studies shapes, and for a breakthrough that might help scientists figure out nothing less than the shape of the universe.
But besides shunning the medal, academic colleagues say he also seems uninterested in a separate, $1 million prize he might be awarded for his feat, which proved a theorem about the nature of multidimensional space that has stumped people for 100 years.
The Fields Medal was announced at the International Congress of Mathematicians, an event held every four years, this time in Madrid.
Three other mathematicians - another Russian, a Frenchman and an Australian - also won Fields honours this year. They received their awards from King Juan Carlos to loud applause from delegates to the conference. But Perelman was not present.

Russian mathematician Grisha Perelman is on the verge of collecting $US1 million ($1.35 million) for solving the Poincare Conjecture. one of the seven greatest mathematical problems of all time, and was first posed by French mathematician Henri Poincare in 1904.

"The word is he's got it. But no one wants to say so in case they're wrong" - mathematician Thomas Hales of the University of Pittsburgh.

According to Professor Devlin, a mathematician at Stanford University in California, the conjecture proposes a way to tell if a bizarre-looking object is an ordinary three-dimensional object in disguise, and is about the "mathematics of smooth behaviour".

The Millennium Prizes were established in 2002 by the Clay Mathematics Institute in Cambridge, Massachusetts, as a challenge to mathematicians.
Four years ago, Perelman thought he had cracked the problem. But the Clay Mathematics Institute rejected his solution, or proof. It did not meet the institute's strict requirements: a peer-reviewed publication of the work, as well as a two-year waiting period to see if the solution stood up to scrutiny.
Professor Devlin, for one, predicts that the CMI is more likely to pay out for the solution of another millennium problem, the so-called Reimann Hypothesis.
It looks at how randomly prime numbers -- divisible only by themselves or 1 -- are sprinkled along a line of numbers. Together with three other millennium problems, the hypothesis is key to internet security.