Methuselah Star

A relic from the early universe is racing through Libra. It’s moving across the constellation at 800,000 miles per hour. That’s far faster than most of the stars around us. So it’ll move out of Libra in the blink of a cosmic eye. The star is HD 140283. But it also has a nickname – the Methuselah Star. That’s because it’s probably about 13 billion to 14 billion years old. Since the universe itself is only 13.8 billion years old, that makes the star one of the oldest anywhere. Astronomers have pieced together several bits of evidence to arrive at that age. The key bit is the star’s composition. It has very low levels of elements that are heavier than hydrogen and helium, the simplest elements. Heavier elements were created in the hearts of stars, then spewed into space when the stars died. Some of these elements then were incorporated into later generations of stars. HD 140283 has less than half a percent as much iron as the Sun, with slightly higher levels of oxygen and a few other elements. Those abundances tell astronomers the star must have been born when the universe was brand new. As night falls, the star is to the lower left of Zubeneschamali, Libra’s leading light. It’s too faint to see with the eye alone, but it is visible through binoculars. Script by Damond Benningfield