Young Universe Expanded Slowly During Last 14 Billion Years, Expansion Slowed and then Sped Up
Astrophysicist Kyle Dawson stands in front of the 2.5-meter Sloan Telescope at Apache Point Observatory in New Mexico. Photo Credit: Dan Long, Apache Point Observatory
Nov. 12, 2012 – Like a roller coaster that crawls slowly uphill and then zooms downhill, the universe expanded at a much slower rate 11 billion years ago than it has during the past 5 billion years, says a new study co-authored by Kyle Dawson, a University of Utah astrophysicist.
Light from 60,000 super-bright objects known as quasars served as flashlights to illuminate hydrogen gas between Earth and objects in the distant, early universe.
“We reconstructed a 3-D map of the hydrogen gas, and from the map, we learned about the processes by which the universe expanded and grew in the first 3 billion years,” says Dawson, an assistant professor of physics and astronomy at the University of Utah and a member of the third Sloan Digital Sky Survey, or SDSS-III, which conducted the study.
Scientists believe the universe formed some 13.8 billion years ago in a sudden expansion of matter and energy known as the Big Bang. Previous research showed its expansion has been speeding up for the past 5 billion years. The new study – performed using the 2.5-meter Sloan Telescope at Apache Point Observatory in New Mexico – is the first to make measurements showing expansion of the universe was slowing for the first 3 billion years after the Big Bang. The expansion later crested the top of the “roller coaster” and began to expand more rapidly some 5 billion years ago.