The universe is expanding faster than previously believed; the surprising discovery will test Albert Einstein’s theory of relativity, which has stood the test of time, so far.
The Hubble Space Telescope has made measuring the distances to stars more accurate than ever before. The team of astronomers made the discovery while refining the measurement of how fast the universe is expanding, a value called the Hubble constant, reducing the uncertainty to only 2.4 percent.
The team, led by Nobel Laureate Adam Riess from the Space Telescope Science Institute, discovered the universe is expanding between five and nine percent faster than what had been previously calculated. A consequence of this could be that the universe ends up ripping itself apart.
If confirmed, the discrepancy could mean either the measurement of cosmic microwave background radiation is wrong, or that there is some kind of unknown physical phenomenon that is speeding up the expansion of space. Alex Filippenko, a UC Berkeley professor of astronomy and co-author of the paper said:
“If you really believe our number — and we have shed blood, sweat, and tears to get our measurement right, and to accurately understand the uncertainties — then it leads to the conclusion that there is a problem with predictions based on measurements of the cosmic microwave background radiation, the leftover glow from the Big Bang.
“Maybe the universe is tricking us, or our understanding of the universe isn’t complete.”
One possible explanation is a new type of subatomic particle (perhaps the hypothesized fourth flavor of neutrino) that may have changed the balance of energy in the early universe, so called dark radiation (which accelerates the expansion of the universe). Or perhaps Einstein’s general theory of relativity, the basis for the Standard Model, is slightly wrong. Riess explained in a statement:
“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.”
According to ESA: “This refined determination of the Hubble constant was made possible by making precise measurements of the distances to both nearby and faraway galaxies using Hubble. The improved distance measurements were made by streamlining and strengthening the cosmic distance ladder, which astronomers use to measure accurate distances to galaxies.
“The team compared these measured distances with the expansion of space as measured by the stretching of light from receding galaxies and these two values were then used to calculate the Hubble constant.”
The researchers used the Hubble Space telescope to look at variable stars called Cepheids, and Type Ia supernovae, both of which have well known brightness enabling their distance to be accurately determined. Over two and a half years the team then measured the movements of around 2,400 Cepheid stars and about 300 Type Ia supernovae.
It was from these measurements they were able to calculate the universe’s expansion rate (the Hubble constant), to be 73.2 kilometers per second per megaparsec (a megaparsec is 3.26 million light-years). Using this new value, the distance between objects will double in 9.8 billion years.
Even though it will not affect us in the near future, there will be some serious repercussions for the universe in time. Australian researcher and ANU astrophysicist Dr. Brad Tucker told Business Insider:
“If the acceleration is not too fast, the universe will cool as it flies apart, resulting in a big freeze.
“But if the universe can’t keep up with its own acceleration there will be a big rip. The universe will literally rip itself apart, which would be awesome.”