This March, the media was sparked into a frenzy by reports of the first sightings of gravitational waves in the cosmic microwave background. There was talk of ‘breakthroughs’, ‘new frontiers of Physics’, ‘smoking guns’ and, of course, Nobel Prizes. The announcement was made by a team working on data from the BICEP2 telescope, who claimed to have discovered signals in the first ever light emitted in the universe. These signals hint at a time even earlier than that, a time that we will never be able to measure directly and that has teased scientists since its proposal in 1980: inflation.
Inflation is an idea put forward to explain why the universe appears to be at such an even temperature. It suggests that the tiny early universe underwent a period of expansion faster than the speed of light, allowing it to preserve its uniform characteristics.
Since this occurred when the universe was still too hot to emit energy as light for us to detect, it has been impossible to put any more constraints on exactly what kind of inflation happened, which is of key importance to many, very different, competing theories, some of which require infinite other universes. BICEP2’s team claim to have discovered evidence of gravitational waves—often described as ripples in space-time—left over from inflation and imprinted onto the cosmic microwave background, the well-measured radiation permeating our universe from when it had cooled enough to emit light. If true, this could not only add to the body of proof that inflation certainly must have happened, but also determine what energy the field that caused the inflation had, vastly cutting down the array of possible theories.
Recently though, other independent scientists have published their own analysis of the results, and have claimed that they could instead have been caused by dust in our own galaxy. Despite calls to do so, the BICEP team have not retracted their claim of discovery. They have also received criticism for publicising their result too soon, but even if the results do turn out to be false, is that really such a bad thing?
Scientists, when in the media at all, are often presented as lofty individuals already with all the answers, the infallible experts. This possible result has given people who would not normally know or be interested in, an insight into the world of scientific research, with big international teams both competing and working together for results.
Later this year, the team working on the Planck satellite that is also studying the cosmic microwave background will release its results, which could demolish or lend strength to BICEP2’s claims. This is as well as other telescopes and even two balloon-carried detectors that are also currently scanning the skies for the elusive waves. These results will now be reported around the world, even if they themselves do not claim a discovery. Before March this year even people interested in Physics may not have heard about these experiments—now they are so widespread that the Daily Mail recently wrote an article on Loop Quantum Gravity simply because it may validate BICEP2’s results.
Gravitational waves in the cosmic microwave background suddenly becoming ‘fashionable’ benefits scientists as well— the BICEP2 team’s paper was only published on the 19th of June and has already been cited over a hundred times in other papers. Other scientists are checking the results or applying them to their own theories, leading to a wealth of discussion.
These possible results have not only introduced people to one of the great mysteries in modern physics, but also given them a glimpse into the process of solving the mystery, which all detective fans know is often as impressive as the mystery itself. Is gravity waving at us from the early universe? Is it simply dust? The one thing we know for sure is that the game is still afoot.
Other useful links:
The Daily Mail Article I refer to
About BICEP in general
Review paper on inflation and studying the CMB
One of those balloon-carried crazy sounding experiments that I mentioned