STOCKHOLM (AFP) - US scientists David J Gross, H David Politzer and Frank Wilczek won the 2004 Nobel Physics Prize for developing a theory that explains quarks, nature's tiniest building blocks.
"The discovery which is awarded this year's Nobel Prize is of decisive importance for our understanding of how the theory of one of nature's fundamental forces works, the force that ties together the smallest pieces of matter - the quarks," the Nobel jury said Tuesday.
By an elegant mathematical formula, the laureates have enabled science to finally dream about finding explanations for some of nature's greatest enigmas in the cosmos, such as the dark matter that seems to dominate space.
Their work is an important step in scientists' attempts to provide a unified description of all forces of nature -- "a theory for everything".
Science's current best shot at such a theory is the Standard Model of Particle Physics, which describes the smallest objects in nature and how they interact.
The model builds on Albert Einstein's theory of relativity and quantum mechanics, and the laureates are credited with having found the last remaining piece of the puzzle.
Quarks build the protons and neutrons of the atomic nucleus, atoms join up to form molecules, the molecules build up structures, "and in this way the whole universe can finally be described."
The trio's specific discovery, made three decades ago, concerns the so-called strong force, or "colour force", which is dominant in the atomic nucleus.
This force grows stronger as quarks separate and weaken to almost zero as they get closer, a phenomenon that can be compared to a rubber band. The more the band is stretched the stronger the force.
The discovery "was totally unexpected," Gross recalled in 1991.
"Like an atheist who has just received a message from a burning bush, I became an immediate true believer," he said at the time.
The Nobel jury acknowledged that the relevance of the trio's discovery for daily life can appear hard to grasp. But using the example of a coin spinning on a table, it said that 80 percent of the coin's weight is due to the interaction between quarks.
"This year's Nobel Prize is about this interaction," it said.
Contacted by telephone, Gross told Swedish media that he was only somewhat surprised to find himself awarded a Nobel prize.
"I am of course honoured," he said in quotes reported in Swedish, adding the award was "to some extent" expected.
"Over the years as the experimental proof got better and better I knew that the theory was correct. It made sense that this theory should one day share the honours with the other discoveries on fundamental forces."
Wilczek, who was only 21 and Gross' graduate student when the two made their revolutionary discovery, independent of but parallel to Politzer's work in the same area, told Swedish news agency TT he was having a hard time regaining his composure after the news, and said his parents' reaction was most "touching".
"This means a lot to them. They grew up during the depression in difficult conditions so this has been a long journey for my family," he said.
The laureates will receive a gold medal and share a cheque for 10 million Swedish kronor (1.1 million euros, 1.3 million dollars) at the formal prize ceremony held, as tradition dictates, on December 10, the anniversary of the death in 1896 of the prize's creator Alfred Nobel.
On Monday, the Nobel Medicine Prize went to US research duo Richard Axel and Linda Buck for their pioneering work on mammals' sense of smell.
The Chemistry Prize will be announced on Wednesday, the Literature Prize on Thursday and the Peace Prize on Friday. This year's edition of the coveted prizes rounds off with the announcement of the Economics Prize on October 11.