HOW CAN A STAR BE OLDER THAN THE UNIVERSE?

For more than 100 years, astronomers have been observing a curious star located some 190 light years away from Earth in the constellation Libra. It rapidly journeys across the sky at 1.3 million kilometres (800,000 miles) per hour. But, more interesting than that, HD 140283 – or Methuselah as it's commonly known – is also one of the universe's oldest known stars.

In 2000 scientists sought to date it using observations via the European Space Agency's (ESA) Hipparcos satellite that estimated an age of 16 billion years old. Such a figure was quite impressive, and rather mind-blowing, yet also pretty baffling. As Professor Howard Bond of Pennsylvania State University points out, the age of the universe – determined from observations of the cosmic microwave background – is 13.8 billion years old. “It was a serious discrepancy,” he tells us.

Taken at face value, it raised a major problem. How could a star be older than the universe? Or, conversely, how could the universe be younger? It was certainly clear that Methuselah – named in reference to a biblical patriarch who is said to have died aged