Universe expanding 9% faster than thought

Nasa and the European Space Agency jointly announced Friday that the universe was expanding 5% to 9% faster than predicted – a discovery that could test part of Albert Einstein’s theory of relativity, a pillar of cosmology that has withstood challenges for a century.

The two agencies said they reached their conclusion after using the Hubble space telescope to measure the distance to stars in 19 galaxies beyond the Milky Way.

The rate of expansion did not match predictions based on measurements of radiation left over from the Big Bang that gave rise to the known universe 13.8bn years ago, they said.

Physicist and lead author Adam Riess said: “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. But now the ends are not quite meeting in the middle and we want to know why.”

The discovery also stirs hypotheses about what constitutes the 95% of the cosmos that emits no light and no radiation, scientists said.

One possibility for the discrepancy is that the universe has unknown subatomic particles, similar to neutrinos, that travel nearly as fast as the speed of light, about 300,000km per second.

Another idea is that so-called “dark energy”, a mysterious, anti-gravity force discovered in 1998, may be shoving galaxies away from one another more powerfully than originally estimated.

“This may be an important clue to understanding those parts of the universe that make up 95% of everything and that don’t emit light, such as dark energy, dark matter and dark radiation,” said Riess.

In 2011, Riess shared the Nobel prize in physics for the discovery that the expansion of the universe was speeding up.