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Washington (AFP) – The Hubble Space Telescope has detected the most distant star ever observed: called Earendel, its light has traveled for 12.9 billion years to reach us.
Rivaling the largest known stars, scientists estimate its mass to be at least 50 times that of our Sun, and millions of times brighter than it.
The star holding the previous record was also observed by Hubble in 2018. But the latter existed in a Universe then 4 billion years old, compared to only about 900 million years after the Big Bang for Earendel, according to Researchers.
The discovery was published Wednesday in the prestigious scientific journal Nature.
“At first, we almost didn’t believe it,” said lead author Brian Welch of Johns Hopkins University in Baltimore, USA, in a statement.
It was he who had the privilege of naming this star: Earendel means “morning star” in Old English.
The star “existed so long ago that it might not have been made of the same raw materials as the stars around us today,” the researcher explained.
“Studying Earendel will provide a window into a period of the Universe that we are unfamiliar with, but which led to everything we know today,” he added.
This star will thus be a prime target for the new James Webb Space Telescope, currently being calibrated in space. James Webb will observe this new star this year, said in a press release the European Space Agency (ESA), which operates the telescope with NASA.
Just as the sound of a moving object fades away, the light wave gradually stretches and changes from the visible frequency to the naked eye to that of the infrared.
Unlike Hubble, which has only a small infrared capacity, James Webb will only operate in these wavelengths, allowing us to go back even further.
Until now, only groups of stars could be observed at such a distance, without being able to distinguish a star in particular.
But Earendel had a cosmic help: a phenomenon called gravitational lensing. A cluster of galaxies, located between us and the star, acts as a magnifying glass amplifying the light of the object.
The ESA compares this effect to ripples on the surface of the water, which in good weather can create amplified light beams on the floor of a swimming pool.
This rare alignment should last for years to come, according to astronomers.
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