The universe is looking younger every day, it seems.
New calculations suggest the universe could be a couple billion years younger than scientists now estimate, and even younger than suggested by two other calculations published this year that trimmed hundreds of millions of years from the age of the cosmos.
The huge swings in scientists' estimates — even this new calculation could be off by billions of years — reflect different approaches to the tricky problem of figuring the universe's real age.
"We have large uncertainty for how the stars are moving in the galaxy," said Inh Jee, of the Max Plank Institute in Germany, lead author of the study in yesterday's journal Science.
Scientists estimate the age of the universe by using the movement of stars to measure how fast it is expanding. If the universe is expanding faster, that means it got to its current size more quickly, and therefore must be relatively younger. The expansion rate, called the Hubble constant, is one of the most important numbers in cosmology. A larger Hubble Constant makes for a faster moving — and younger — universe.