NASA’s Hubble Space Telescope has returned some weird data from deep space and, if true, it could be about to change things in a big way. The Hubble Space Telescope has been in our orbit for nearly 30 years, returning data and photographs – both beautiful and scientifically important – of our universe. But now, a team of astronomers that has used the telescope for the past six years to create a more accurate ‘yardstick’ on the rate of expansion of the universe has found something odd – so odd that if it isn’t a bug in the system, these astronomers will need to rewrite the rules on physics.
This yardstick involved measuring the distances between galaxies and using their stars as milepost markers, a value known as the Hubble Constant. When the team conducted the study this time around, however, it extended the number of stars analysed to distances up to 10 times farther into space than previous Hubble results. The team’s value reinforces the disparity with the expected value derived from observations of the early universe’s expansion, 378,000 years after the Big Bang, which was roughly 13.8bn years ago. These measurements were recorded by the European Space Agency’s Planck satellite, which maps the cosmic microwave background left after the Big Bang. When compared with these latest results, the value differs by only 9pc. The new Hubble measurements help to reduce the chance that the discrepancy in the values is a coincidence, to one in 5,000. “The community is grappling with understanding the meaning of this discrepancy,” said lead researcher and Nobel Laureate Adam Riess. “Both results have been tested multiple ways, so, barring a series of unrelated mistakes, it is increasingly likely that this is not a bug, but a feature of the universe.”
Riess and his team have a few suggestions, mostly surrounding mysterious dark energy that shrouds 95pc of the universe in darkness. It is possible, the team said, that this dark energy is pushing out galaxies farther into the distant universe at an accelerating but differing rate, whereas previous estimates took the expansion as being a constant value. A second option is that there is a new subatomic particle out there that travels close to the speed of light, putting it among a group of speedy particles known as ‘dark radiation’. Another third dark possibility is that dark matter – an invisible form of matter not made up of protons, neutrons and electrons – interacts more strongly with normal matter or radiation than previously assumed. All three realities would mean that astrophysicists would need to go back to the drawing board, as the above create inconsistencies in theoretical models. Unsurprisingly, the universe is weird, and now Riess and his colleagues are going to try and find what the answer is.
Credit: Colm Gorey for Siliconrepublic, 23 February 2018.