LONDON (Reuter - Feb 14, 1997) - Generations of astrophysicists may have miscalculated the size and age of the universe, according to initial data from a European Space Agency (ESA) satellite presented at a meeting of scientists Friday.
Results from the Hipparcos satellite suggest the observable universe could be around 10 percent bigger, and therefore a little older, than previously thought, indicating the yardstick used since 1912 to measure the cosmos could be wrong, scientists said.
The results, presented by Michael Feast of the University of Cape Town, also take four billion years off the age of the oldest stars, clearing up the paradox that some were apparently older than the universe.
"It's all coming together rather nicely," said ESA Professor Michael Perryman, at the Royal Astronomical Society in London.
Hipparcos circled the earth from 1989 to 1993, using telescopes and computers to map the positions of 100,000 stars.
Scientists said the mission was a breakthrough, since the satellite was unaffected by thermal and gravitational variations within the earth's atmosphere. It gave a stereoscopic picture of space rather than a flat projection like telescopes on earth and could gauge distances more accurately.
"Hipparcos has taken us right back to our roots to check the fundamentals are correct," said Jasper Wall of the Royal Greenwich Observatory.
The measurement of distances in the cosmos relies on the brightness of winking stars called Cepheids. Hipparcos shows them to be brighter and further away than previously believed.
Looking at Cepheids in other galaxies, the scientists worked out the age of the oldest stars to be 11 billion years. That is considerably less than previous estimates of nearly 15 billion which did not fit in with the age of the universe itself, which scientists now believe to be 12 billion years, about one billion more than previously thought.
Speakers at the conference hailed the ironing out of this discrepancy as a major step forward in one of the touchiest subjects in cosmology.
"I hope we've cured a nonsensical contradiction that was a headache for cosmologists," said Feast.
Hipparcos, named after a Greek astronomer, was conceived by two teams of European scientists over 16 years, and around 2,000 space engineers worked on the project.
Friday's speakers called it "a triumph in terms of European collaboration" and said they were delighted with the results.
Earlier, the ESA said the Hipparcos program, one of the largest computations in the history of astronomy, had achieved a hundredfold improvement in the accuracy of star positions. Feast said he hoped further results, to be presented in Venice, Italy, in May would confirm their conclusions.
Original file name: CNI - Age.Size of universe
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