The universe is expanding faster than it used to, meaning it's about a billion years younger than we thought, a new study by a Nobel Prize winner says.

一位诺贝尔获奖者称，宇宙的膨胀速度比以前要快，这意味着它比我们想象中要年轻10亿年。

At issue is a number called the Hubble constant, a calculation for how fast the universe is expanding. Some scientists call it the most important number in cosmology, the study of the origin and development of the universe.

Using NASA's Hubble Space Telescope, Johns Hopkins University astronomer Adam Riess concluded in this week's Astrophysical Journal that the figure is 9% higher than the previous calculation, which was based on studying leftovers from the Big Bang.

The trouble is, Riess and others think both calculations are correct.

Confused? That's OK, so are the experts.

They find the conflict so confounding that they are talking about coming up with "new physics," incorporating perhaps some yet-to-be-discovered particle or other cosmic "fudge factors" like dark energy or dark matter.

"It's looking more and more like we're going to need something new to explain this," said Riess, who won the 2011 Nobel in physics.

NASA astrophysicist John Mather, another Nobel winner, said this leaves two obvious options: "1. We're making mistakes we can't find yet. 2. Nature has something we can't find yet."

Even with the discovery, life continues on Earth the way it always has. But to astrophysicists trying to get a handle on our place in this expanding universe, this is a cosmic concern.