BALTIMORE, June 2 (UPI) -- A discrepancy between galactic distances in the infant universe and more modern measurements suggests the universe is expanding at a faster pace than previously predicted.
Astronomers recently used the Hubble Space Telescope to measure the distance between 19 galaxies with unprecedented accuracy. The numbers suggest the universe is expanding between 5 and 9 percent faster than the rate derived from galactic distances measured in the early universe, just after the Big Bang.
Researchers believe the discrepancy may offer insights into the nature of dark matter.
"This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don't emit light, such as dark energy, dark matter, and dark radiation," Adam Riess, an astronomer with the Space Telescope Science Institute and Johns Hopkins University, said in a news release.
Dark matter and the dark energy it carries may explain the acceleration of the universe's expansion.
The most recent calculation of the universe's rate of expansion, called the Hubble constant, is believed to be the most accurate ever -- with a margin of error, or rate of uncertainty, of just 2.4 percent.
Astronomers expected the new calculations to forge an agreeable link with those derived from observations of the Big Bang afterglow collected by NASA's Wilkinson Microwave Anisotropy Probe and the European Space Agency's Planck satellite.
"You start at two ends, and you expect to meet in the middle if all of your drawings are right and your measurements are right," Reiss said. "But now the ends are not quite meeting in the middle and we want to know why."
Astronomers are continuing to go over the data to try to reduce the margin for error even further, but it appears likely researchers will now be faced with the task of explaining the disagreement between the two Hubble constants.