WASHINGTON (AP) – The Universe is expanding faster than it used to, which means that it is about a billion years younger than we thought, according to a new Nobel Laureate study. And that shivers through the world of physics, allowing astronomers to reconsider some of their most basic concepts.
It's about a number called the Hubble constant, a calculation of how fast the universe expands. Some scientists call it the most important number in cosmology, the study of the origin and evolution of the universe.
Using NASA's Hubble Space Telescope, Johns Hopkins University astronomer Adam Riess concluded in the Astrophysical Journal of the Week that the figure is 9% higher than the previous calculation, which was based on the study of leftovers from the Big Bang ,
The problem is that Riess and others believe that both calculations are correct.
Confused? This is also the case with the experts.
They find the conflict so confusing that they speak of developing "new physics" that may contain particles or other cosmic "fudge factors" like dark energy or dark matter yet to be discovered.
"It seems more and more to be that we need something new to explain that," said Riess, who won the 201
NASA astrophysicist John Mather, also a Nobel laureate, said there are two obvious options: "1. We make mistakes we can not find yet. 2. Nature has something we can not find yet.
Even with the discovery, life on earth continues as it always has been. For astrophysicists trying to get our place in this expanding universe under control, this is a cosmic concern.
In order to determine his measurement of the Hubble constant, Riess looked at some not so distant stars.
Riess observed 70 Cepheid stars – stars pulsing at a well-observed frequency – calculated their distance and rate and compared them to a particular type of supernova used as a dipstick. It took about two years for the Hubble telescope to make these measurements, but Riess finally calculated an expansion rate of 74.
The use of this 74 number means that the universe is between 12.5 and 13 billion years old. This is much younger than the estimates of 13.6 to 13.8 billion.
"Hey, that's good news. Everyone may look younger, "said Riess.
THE OLD MEASUREMENT
In 2013, the European Planck satellite helped scientists anticipate a much slower rate of expansion of about 67, but this happened in a completely different, more inclusive way more complicated and less direct way and by looking at a much earlier time when the universe was still a toddler.
The Planck team studied background radiation from a time just 370,000 years after the Big Bang Hot spots in this radiation have helped scientists figure out how large the patches were, allowing them to see how far they were looking.
This team then fed these calculations into the standard model that astronomers use for the Universe – based on Einstein's more general Theory of relativity, inter alia, considers the lower expansion rate in the known acceleration of the universe. The end result: a 13.8 billion year old universe.
Riess calculated the probability that the inequality between the two calculations was a coincidence of 1: 100,000.
Even if there's a chance the Riess team or the Planck team is out, astronomers say both are right.
Both calculations are meaningful and "nobody can find anything wrong at this time," said renowned University of Chicago astrophysicist Wendy Freedman. Other external experts praised the research of both teams.
If this is the case, astrophysicists must make adjustments in Einstein's general theory of relativity.
"You have to put something in the universe that we do not know about," said Chris Burns, astrophysicist at the Carnegie Institution for Science. "That always makes you restless."
In the past, astronomers have added elusive dark energy and dark matter to explain why calculations do not add up, from an Einstein theory that was once rejected. Now they say they have to do something similar again.
It could be that there is an extra "turbocharger" due to an odd momentum of dark energy – an invisible expansion force that fits well with Einstein's theories – that caused the acceleration. On expansion, said Riess.
Or it could be a new matter particle that was not discovered, Burns said.
"We have this dark sector, which already has two components, and maybe we discover a third," said Lloyd Knox, member of the Planck team at the University of California, Davis. "That's a scary prospect. Will we always only introduce fudge factors?
A THIRD APPROACH
Astronomers at the University of Chicago, led by Freedman, spent five years searching for stars other than Riess to obtain a third calculation of the system's expansion rate. You have just submitted your work to the same journal. Freedman did not reveal her number, but said it was between the other two figures.
Twenty years ago, Freedman was part of a similar debate about the Hubble constant when there were only a few measurements to work with.
An exciting journey to understand the origin of the universe, "she said.
Follow Seth Borenstein on Twitter: @borenbears .
The Associated Press The Department for Health and Science is supported by the Howard Hughes Medical Institute's Department of Science Education, which is solely responsible for the content.