Age may only be a number, but it turns out some of the oldest stars in the universe could be a lot younger than believed, according to new results from the Planck telescope. While scientists had previously estimated that the first stars began to shine 440m years after the Big Bang, itself pegged at 13.8 billion years ago, new results from the decommissioned ESA space telescope suggest that may have been off by as much as 100m years. Spilling the stars' age secrets are freshly calculated maps of cosmic background radiation, that help explain when reionization of the universe began.
Reionization is the process by which the non-visible ultraviolet light cracked apart hydrogen and produced visible starlight. Before that happened, the universe was in its so-called "dark age", scientists believe, where there was none of the starlight we're used to seeing now.