In Cosmic Numbers, the Universe Is Now 13.7 Billion Years Old

Scientists using a robotic NASA probe have determined with precision the age of the universe -- 13.7 billion years -- and figured out when stars began to shine.

Astronomers have been closing in on these numbers for decades, but a spacecraft now about a million miles from Earth has been able to look back to nearly the dawn of time to find the answers, NASA researchers said Tuesday.

Stars started shining just 200 million years after the theoretical big bang, scientists said in announcing findings of the so-called WMAP mission, which gazed on the universe when there were no stars, no galaxies, nothing except minute differences in temperature.

These temperature differences were as little as one-millionth of a degree, but that was enough to create vast hot and cold spots that signaled the beginning of the clumping that eventually became every known structure in the universe, the scientists said.

WMAP -- short for Wilkinson Microwave Anisotropy Probe -- looked back in time to just 380,000 years after the big bang that many astronomers believe gave birth to the universe.

That is further back in time than even the orbiting Hubble Space Telescope can see.

The image that WMAP produced is a view of the entire sky seen as a spotted oval, with hot areas indicated by yellow and red and cool areas by blue and turquoise.

An earlier NASA space probe, the Cosmic Background Explorer, produced similar colorful ovals in 1992, but where the earlier craft saw blobs, WMAP created detailed mosaics of color, a much sharper cosmic “baby picture.”

Charles Bennett, principal investigator for WMAP, was elated.

“WMAP has returned a goldmine of new results.... We have produced a new, detailed, full-sky picture of our infant universe, the afterglow of the big bang,” said Bennett, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md.

“It’s brought the universe into sharp focus.”

John Bahcall of the Institute for Advanced Study at Princeton University offered perspective on the find, but he was no less effusive.

“The announcement today ... represents a rite of passage for cosmology, from speculation to precision science, and I am thrilled by the precision of the results,” he said.

To explain the scope of the find, Bahcall suggested that it was as if the mature universe that exists now was equivalent to a 50-year-old human and the WMAP mission managed to look back in time to take precise calculations of what that human was like as a 12-hour-old baby, down to the exact size of its toes.

Results from WMAP were scheduled to be presented last week, but they were delayed in deference to those mourning the Feb. 1 loss of the space shuttle Columbia and its seven crew members.

“We believe that the best way to honor the seven astronauts on Columbia who dedicated their lives to the NASA science mission is to continue that science mission to explore the universe,” said Anne Kinney, director of NASA’s astronomy and physics division.