NASA's Hubble Space Telescope has found the oldest burned-out stars in our Milky Way Galaxy. These extremely dim and old "clockwork stars" provide a completely independent reading of the age of the universe. By measuring the temperature of white dwarf stars in a globular star cluster, astronomers can estimate their ages. Hubble's sensitive detectors came up with an age of 12 to 13 billion years, dovetailing nicely with other independent measurements placing the universe's age at 13 to 14 billion years.
Publication: April 24, 2002