Hubble Space Telescope Finds Oldest Star Ever Discovered
TThese are 30-year olds that have not lived in a world where the Hubble space telescope has been observing the cosmos. This venerable observatory was built in 1990 by George H.W. Bush was at the White House. Teenage Mutant Ninja TurtlesIt was also the top-selling movie at the box office. Gas went as low as a dollar a gallon. It’s only fitting then that this week, the very old telescope made a very important discovery of an exceedingly old star—the oldest, indeed, that’s ever been detected.
NASA announces the release of a paper. NatureHubble reported that it has found a star at 12.9billion years old. That means the galaxy existed in 7% of our current age. Hubble spotted the previous record holder in 2018 at a young 9 billion year old. This was when the universe was only 30% its current age.
The new star, dubbed Earendel, which means “morning star” in Old English, does not even exist anymore—its light has been traveling to us over the past nearly 13 billion years, long after the star itself has winked out. The late Earendel might not have been detected at all if it weren’t for a trick of physics and optics known as gravitational lensing. Albert Einstein originally proposed gravitational lensesing. This is when light from distant objects passes around an object that’s larger and more massive (e.g. a star). Gravitational lensing is when light from a distant object passes around a closer, more massive object (like a star). This acts as if he or she were focusing on the other side of the interfering one.
This lens wasn’t just another galaxy or star in the sky, it was a whole galactic cluster. Earendel’s position in space is especially fortuitous, with its light passing directly over a discrete ripple in spacetime—known as a “caustic”—caused by the cluster. In a way, the caustic magnified magnification making it appear brighter.
“Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together,” Brian Welch, an astronomer with Johns Hopkins University and the lead author of the paper, told NASA. “The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent.”
Welch and his collaborators have found that Earendel had a mass approximately 50 times greater than our sun, and a brightness of millions. The Earendel’s mass would have been about 50 times that of our sun and millions of times brighter. There wouldn’t be any heavier metals in it. As such, Earendel is what NASA calls “the first evidence of the legendary Population III stars,” which are the first stars to have lit their nuclear furnaces after the Big Bang.
Earendel may have been Hubble’s to find, but the aging telescope will now pass the work of studying the object in greater detail onto the brand new James Webb Space Telescope, which was purpose-built to observe in the infrared spectrum in which the ancient star principally shines. Webb is capable of doing even more.
“With Webb we will see stars even farther than Earendel,” Welch told NASA. “I would love to see Webb break Earendel’s distance record.”
The original version of this story appeared in TIME Space. This weekly newsletter covers all things space. Sign up now
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