The star formed when the universe was “only” a billion years old, the early years of our universe, which is now 13.8 billion years old. The light from the star had been traveling for nearly the entire life of the universe, before it was picked up by the Hubble telescope.
Usually, very distant stars are indistinguishable: they are clustered into galaxies, and they are just faint points in telescope images at these distances. Under very specific circumstances, and in special ways, this star was nonetheless visible. The researchers We call the gas ball Earndel, Old English for “morning star”.
galaxy cluster
The new record is a huge improvement over the old record: Earndale is four times further away than the previous “farthest star”, also discovered by Hubble. Galaxies have been observed far from Earth, but have never been observed as a single star.
To extract Earndel from his galaxy and visualize them individually, the researchers used a special “lens”: a group of galaxies. This assembly works as a gravitational lens. Such a lens is created when objects of great mass, and therefore a lot of gravity, excite rays of light from objects behind them, such as a massive lens in space.
When a gravitational lens is placed precisely between an orb and the Earth, the lens makes the object thousands of times brighter and easier to see. The fact that this lens specifically made Arendelle visible is purely coincidental: the researchers were unable to determine which group of galaxies they chose.
look at history
Moreover, Earendel is visible because it is an unusually huge and bright star. Researchers currently estimate that it is 50 times larger than the Sun, and millions of times brighter. By the way, Earndel died long ago: these types of heavy stars burn their fuel quickly. The light we see now is a brief history.
Rychard Bouwens (Leiden University), an expert on the young universe who is not connected to this research, calls it “an impressive discovery, which provides an opportunity to study the young universe.” When the universe first appeared, there were fewer chemical elements available to form stars than there are today. This is why it is so interesting for researchers to be able to see stars from that era. “If this was indeed a star, it would give insight into how the stars shined at that time, which we can compare to the stars here and now.”
With that, Bouwens has a hand in his arm. “The researchers have done a good job and provided strong evidence that this may indeed be a star, but this is not yet certain.” He sure looks forward to Hubble’s successor, James Webb. This space telescope will be operational in a few months and there is already a plan to go see Earendel.
