Previous claims the the BICEP2 project had detected gravitational waves from the early universe have been disproved.
Scientists had reported a possible detection, but have now retracted their claims following joint data analysis between the European Space Agency’s Planck space mission and the ground-based BICEP2 experiment. Although the analysis proved that signals from ancient gravitational waves had not been detected, it did give scientists a far more detailed picture of what such signals should look like, which will help future research.
“By analysing both sets of data together, we could get a more definitive picture of what’s going on than we could with either dataset alone,” said Charles Lawrence, Planck project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.
“The joint analysis shows that much of the signal detected by BICEP2/Keck is coming from dust in the Milky Way, but we cannot rule out a gravitational wave signal at a low level. This is a good example of how progress is made in science, one step at a time,” Lawrence said.
Both Planck and BICEP2/Keck were designed with the aim of measuring relic radiation, which was emitted shortly after the birth of our universe 13.8 billion years ago. This so-called “fossil” radiation, also known as the cosmic microwave background (CMB), is an extremely important source of information about the history of the universe according to ndtv.com.
Further research needed on gravitational waves
Both BICEP2 and the Keck Array, its sister project, are located at the South Pole. The U.S. National Science Foundation funds both projects, which focus their monitoring efforts on a small area of the sky above the South Pole. On the other hand, Planch measures the CMB over the whole sky from its position above the Earth.
Data analysis showed that most of the signal which BICEP2 detected was probably due to dust in the Milky Way, but there was a small part which remains a mystery. Detection of CMB from the universe’s inflationary period is uncertain. The study has set an upper limit on the amount of gravitational waves produced during the inflationary period, and they may have been produced at too low of a level to be detected by the current analysis.
NASA reports that a paper on the latest research is currently under peer review.