Americans John C. Mather and George F. Smoot won the 2006 Nobel Prize in physics yesterday for work that helped cement the big bang theory of the universe and deepen understanding of the origin of galaxies and stars.

Mather, 60, works at the NASA Goddard Space Flight Center in Greenbelt, Maryland, and Smoot, 61, works at the Lawrence Berkeley National Laboratory in Berkeley, California.

Their work was based on measurements done with the help of NASA's COBE satellite, launched in 1989. They were able to observe the universe in its early stages about 380,000 years after it was born. Ripples in the light they detected also helped demonstrate how galaxies came together over time.

"The COBE results provided increased support for the big-bang scenario for the origin of the Universe, as this is the only scenario that predicts the kind of cosmic microwave background radiation measured by COBE," the academy said in its citation.

The big-bang theory states that the universe was born billions of years ago from a rapidly expanding dense and incredibly hot state.

Reached at his home in Berkeley, Smoot said in an interview he was surprised when he got the call from the Nobel committee in the middle of the night.

"I was surprised that they even knew my number. After the discovery I got so many calls I unlisted it," he said.

"The discovery was sort of fabulous. It was an incredible milestone. Now this is a great honour and recognition. It's amazing," he said.

Mather said he was "thrilled and amazed" at receiving the prize.

"I can't say I was completely surprised, because people have said we should be awarded, but this is just such a rare and special honour," Mather said in a telephone interview with the Nobel committee.

He said he and Smoot did not realize how important their work was at the time of their discovery.

With their findings, the scientists transformed the study of the early universe from a largely theoretical pursuit into a new era of direct observation and measurement.

"The very detailed observations that the laureates have carried out from the COBE satellite have played a major role in the development of modern cosmology into a precise science," the academy said.

Last year, Americans John L. Hall and Roy J. Glauber and German Theodor W. Haensch won the prize for work that could improve long-distance communication and navigation.

This year's award announcements began on Monday with the Nobel Prize in medicine going to Americans Andrew Z. Fire and Craig C. Mello for discovering a powerful way to turn off the effect of specific genes, offering new hope for fighting diseases as diverse as cancer and AIDS.

The winner of the Nobel Prize in chemistry will be named today. The Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel will be announced on October 9. The winner of the peace prize the only one not awarded in Sweden will be announced on October 13 in Oslo, Norway.

Source: China Daily