Quaking stars to tell the age of the cosmos

摘要

Despite the massively powerful telescopes now available for astronomy from Earth and space, science still has no reliable measure of how long it has taken the Universe to reach its present state after the "Big Bang" propelled all matter ever-outward through space. Two different "clocks" have been disagreeing on the true age of the cosmos. The big picture people - the cosmologists - measure the speeds at which galaxies are receding from the centre. Working backwards to a common point, they reckon the Universe is about 10-12 billion years old. Meanwhile, working out how long individual stars take from birth to death, the astrophysicists calculate that stars are half as old again: about 15 billion years. Both angles, however, are beset with inherent errors and this is hindering the development of a unified explanation of how galaxies and stars behave.