How did an infinitesimally small dot expand in a trillionth of a second into the entire universe we see today? A team of scientists, including Princeton physicists, NASA scientists and academics across North America, is leading the way to provide the answer with newly-found data.
The data provide strong evidence for an "inflationary" model of the universe's development, in which the cosmos experienced an extraordinarily rapid expansion in a fraction of the moment after it burst into existence.
"These results give strong evidence for the simple models proposed for the universe's early development. Inflation has passed one of its most significant tests," said team member and University astrophysics professor David Spergel, one of the scientists who presented the team's most recent results at a colloquium held in McDonnell Hall yesterday.
The presentation included three years' worth of refined and analyzed measurements from the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite orbiting the sun that measures a cosmic background of microwave radiation dating back to the earliest eras of the universe. The WMAP can detect temperature fluctuations "at levels finer than one-millionth of a degree," according to a press release regarding the results by the NASA Goddard Space Flight Center.
According to NASA's press release, "The new WMAP data, combined with other cosmology data, also support established theories on what has happened to matter and energy over the past 13.7 billion years since its inflation."
The WMAP satellite uses separate antennas aimed at different areas of the cosmos in order to give a map of the entire sky. This map, which the scientists used extensive statistical techniques and cross-comparisons between data to construct, provides a snapshot of the temperature and magnetic polarization of the early universe.
The WMAP team first gathered satellite data in 2003 and has since refined its results and reduced error margins with additional information collected over the past three years.
"The overall data is incredible," Spergel said, adding in his presentation that error margins have been reduced "by a factor of three with the three new years of data."
"With more perspective and experience with the satellite, we've developed a much more accurate map," team member and physics professor Lyman Page said during the colloquium, adding, "we need a stable base for our measurements, which the satellite has done very well. It's like a rock — a stable rock."
The data provided by WMAP also reveals insights into the composition of the universe. According to the group's results, only four percent of the universe is composed of atoms, which make up our bodies, the planets and the stars.
The remaining 96 percent of the universe seems to be composed of "dark matter" and "dark energy." Dark matter differs from atoms in that it neither absorbs or emits light, and dark energy acts as a sort of anti-gravity that accelerates the expansion of the universe.
The results presented this week are by no means the end of the work for the WMAP team. "We have even more recent data than these three-year results, since the project has been running for four and a half years," Spergel said, adding that even further refinements in results will be possible with more data.