Universe measured by mapping 260,000 galaxies

By looking at a vast swath of sky, astronomers said they have figured out a way to measure the universe -- using a kind of "cosmological ruler." Finding the cosmic ruler required two teams of scientists to map more than 260,000 galaxies. They concluded that the universe is flat, with ripples that began as the tiniest variations in radiation left over from the big bang, which many cosmologists believe gave birth to the universe. As it cooled after the mega-explosion some 13.7 billion years ago, the infant universe was actually making a sound and those waves produced the ripples, said Daniel Eisenstein, an astronomer at the University of Arizona. The way galaxies are scattered across the sky now corresponds to the sound waves in the early times of the cosmos, Eisenstein told reporters at a meeting of the American Astronomical Society. "We regard this as smoking-gun evidence that gravity has played the major role in growing from the initial seeds in the microwave background [left over from the big bang] into the galaxies and clusters of galaxies that we see around us."

REUTERS