Washington, Feb. 12 (Reuters): 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 1.6 million km from Earth was able to look back to nearly the dawn of time to find the answers, Nasa researchers said yesterday.
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 signalled the beginning of the clumping that eventually became every known structure in the universe, the scientists said.
WMAP — short for Wilkinson Microwave Anisotopy Probe — looked back in time to just 380,000 years after the Big Bang explosion 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 WMAP produced is a view of the entire sky seen as a spotted oval, with hot areas indicated by yellow and red and cool ones by blue and turquoise.
An earlier Nasa probe, the Cosmic Background Explorer, produced similar colourful ovals in 1992, but where the earlier craft saw blobs, WMAP created detailed mosaics of colour, a much sharper cosmic “baby picture.”
Charles Bennett, a scientist at Nasa’s Goddard Space Flight Center who is 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,” Bennett said.