Stars shine light on universe age

Light from four of the oldest stars in our Milky Way galaxy has been analysed in unprecedented detail, writes Steve Farrar.

Astronomers hope their results will help place a more accurate lower limit on the universe's age and reveal more about the eventual fate of our own sun.

The team of German experts used the enormous light-gathering power of the Very Large Telescope at the European Southern Observatory in Chile to get the first spectra from four stars in a globular cluster in our galaxy.

The results, to be published in the journal Astronomy and Astrophysics, identified them as white dwarf stars. These were among the first to flicker into life in the Milky Way but are now coming to the end of their lives and have shrunk to the size of the Earth.

The spectra of their light is distinct and can reveal their temperature, surface gravity and mass and hence allow the precise distance of the globular cluster they are part of to be determined.

Further analysis is expected to allow scientists to gain evidence towards putting an age on the universe.