Jerome Olivier
the universe slowly fades
“The universe is curling up on the sofa and becoming a couch potato,” said Joe Liske, an astronomer at the European Southern Observatory in Garching, Germany, who took part in the study.
Universal dimming is driven by a slump in the rate of new star formation, which peaked about eight billion years ago. Stars shine by fusing hydrogen into helium, but as they consume their cosmic fuel supply, the birth rate of new stars falls dramatically.
A simulated fly-through of the universe as catalogued by the GAMA project, showing the real positions and images of the galaxies that have been mapped so far.
The fading will play out over billions of years, until the universe glows only faintly with a smattering of stars. “It’s not that we can define a point in the future when the universe goes out. A very small amount of activity will continue for billions of years,” Liske said.
The international team used land and space-based telescopes to observe an area of the sky the size of 1000 full moons. They measured light coming from galaxies as near as 500 million light years and as distant as several billion light years away.
The researchers then analysed the light at different wavelengths, ranging from the ultraviolet through to visible and the infra-red. By analysing starlight across so many wavelengths, they could calculate the rate of dimming more accurately than before. The latest measurements, for example, take account of dust particles in space that absorb visible light from stars and re-radiate it in the infra-red.
“We’ve been able to measure quite precisely how fast this dimming is proceeding,” Liske said. “It’s a piece of the puzzle in the history of the universe that reaches all the way back to the Big Bang.”
Source The Guardian
the universe slowly fades
“The universe is curling up on the sofa and becoming a couch potato,” said Joe Liske, an astronomer at the European Southern Observatory in Garching, Germany, who took part in the study.
Universal dimming is driven by a slump in the rate of new star formation, which peaked about eight billion years ago. Stars shine by fusing hydrogen into helium, but as they consume their cosmic fuel supply, the birth rate of new stars falls dramatically.
A simulated fly-through of the universe as catalogued by the GAMA project, showing the real positions and images of the galaxies that have been mapped so far.
The fading will play out over billions of years, until the universe glows only faintly with a smattering of stars. “It’s not that we can define a point in the future when the universe goes out. A very small amount of activity will continue for billions of years,” Liske said.
The international team used land and space-based telescopes to observe an area of the sky the size of 1000 full moons. They measured light coming from galaxies as near as 500 million light years and as distant as several billion light years away.
The researchers then analysed the light at different wavelengths, ranging from the ultraviolet through to visible and the infra-red. By analysing starlight across so many wavelengths, they could calculate the rate of dimming more accurately than before. The latest measurements, for example, take account of dust particles in space that absorb visible light from stars and re-radiate it in the infra-red.
“We’ve been able to measure quite precisely how fast this dimming is proceeding,” Liske said. “It’s a piece of the puzzle in the history of the universe that reaches all the way back to the Big Bang.”
Source The Guardian