Space

Hubble spots most distant single star ever seen, near dawn of universe

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The Hubble Space Telescope has spotted the most distant ever observed
NASA
The Hubble Space Telescope has spotted the most distant ever observed
NASA
An annotated view of Earendel's location (arrow) in the sky. The red line is its host galaxy, distorted by the gravitational lens
NASA, ESA, B. Welch (JHU), D. Coe (STScI), A. Pagan (STScI)

Hubble has spotted the most distant single star ever seen, about 12.9 billion light-years from Earth. The light from this star was emitted not long after the Big Bang, and has been magnified by a foreground galaxy and stretched out by the expansion of the universe.

The star has been nicknamed Earendel, which is apparently an Old English word meaning “morning star” or “rising light.” And that’s fitting for a star that we’re viewing as it was a mere 900 million years after the beginning of the universe. That makes it by far the most distant individual star ever observed – the previous record holder, a blue supergiant by the name of Icarus, is almost 4 billion light-years closer.

That said, these numbers can get a bit confusing. Earendel’s 12.9-billion-light-year distance and Icarus’ 9 billion are in terms of what’s known as lookback time, using the present day as a point of reference. As such, it’s taken 12.9 billion years for Earendel’s light to reach us here on Earth, but in that time the expansion of the universe means the star is now a staggering 28 billion light-years away. Or at least it would be – Earendel is likely long dead by now.

The rate of this universal expansion is one tool used to measure such incredible distances. As light travels through the cosmos, the expanding universe stretches out its wavelengths, shifting it towards the red end of the spectrum. Calculating this redshift can reveal how far away the source was – the greater the redshift number, the further the distance. In this case, Earendel’s redshift was 6.2, which is absolutely huge compared to Icarus’ redshift of just 1.5.

An annotated view of Earendel's location (arrow) in the sky. The red line is its host galaxy, distorted by the gravitational lens
NASA, ESA, B. Welch (JHU), D. Coe (STScI), A. Pagan (STScI)

Although whole galaxies and clusters have been seen at even greater distances, it’s much harder to make out individual stars so far away. As such, the astronomers had a bit of help from a much closer galaxy, which warped spacetime itself thanks to its immense gravity. This bent the light from Earendel and magnified it, making it visible to Hubble through a phenomenon known as gravitational lensing. A lucky alignment between Earth and Earendel made the star pop out from its host galaxy, with its light magnified thousands of times over.

By accounting for the lensing, the astronomers were able to estimate that Earendel has a mass more than 50 times that of the Sun. There is a chance that it’s not one lone star, but a binary system of two, but that doesn’t diminish the achievement of detecting it from so far away.

The astronomers weren’t able to measure other properties of Earendel, such as its temperature, spectrum and whether it’s one or two stars, but these details could be revealed by the James Webb Space Telescope, which is due to begin observations within a few months.

The research was published in the journal Nature. The work is described in the video below.

Source: ESA Hubble

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5 comments
Username
So how did we get here before the light? Since the matter making up the earth presumably travelled out from the big band slower than light speed, any light from way back then should be well past us by now.
Nobody
Since all of the heavier elements supposedly were created and distributed by early supernovae, where are the Hubble photos of galaxies full of them billions of light years away and closer to the presumed time of the big bang? Supernovae should be popping all over in the early universe. The early universe should look like a fireworks show unless current theory is totally wrong which I think it is. I think the universe is much, much older than 13.7 billion years. 50 to 100 billion years would better explain expansion, multiple generations of stars, the mass distribution of heavier elements and the dark matter of generations of burnt out stars that were too small to go nova that are now cold and invisible cinders only detectable by the gravity they produce.





























windykites
The matter making up the Earth was not present for billions of years after the Big Bang (laughingly called that because it was neither big, nor a bang)
We are supposed to believe that the Earth, which contains a full complement of elements, managed to collect them all from rarefied gas and dust blown out from exploding stars
TpPa
good to see the old girl is still going at it, one of our better returns on investment.
Brian M
@:Username -So how did we get here before the light?
As the article explains, its actual a lot further away (was!) due to the Universe expanding, so its nearer to 28 billion light-years away and that light is now only reaching us.

To be honest it does make one feel dizzy if you try to think about it!