Researchers reported on Wednesday that they had discovered the furthest and oldest star ever discovered: a dot of light 12.9 billion years old that had been shining since the Big Bang that created the universe, which occurred barely 900 million years after the Big Bang.
It took 12.9 billion light-years for the light from the star to reach Earth, which is an incredible distance.
Findings like these were made possible by the Hubble Space Telescope, which was used to look for some of the universe’s furthest and most ancient galaxies. Because of a fortunate coincidence, the scientists were able to detect a single star system inside one of the galaxies they were studying.
A doctoral student at Johns Hopkins University in Baltimore who is one of the authors of an article published Wednesday in the journal Nature that reports the finding stated, “It was an unexpected surprise to find something so little.” “It was an unexpected surprise to find something so small.”
Normally, things that are far away are much too faint to be seen in any detail. A solution is provided by Einstein’s theory of general relativity, which explains how gravity bends space in a circular fashion. A huge galaxy cluster that is quite near to us may operate as a lens, magnifying light from stars and galaxies that are considerably more distant from us.
A study conducted with the help of the Hubble Space Telescope has examined 41 galaxy clusters. ‘When you look at a number of incredibly huge galaxy clusters, there’s a fair probability that you’ll be able to locate some pretty highly magnified things behind them,’ Mr. Welch said.
According to Mr. Welch, the galaxy cluster may magnify the brightness of the object behind it by a factor of up to ten, depending on the circumstances.
The light, on the other hand, is not amplified uniformly. A pattern of bright spots at the bottom of a swimming pool, for example, may be created by ripples in space-time, just as patterns of brilliant spots on the top of a pool can be created by ripples on the water’s surface. When the scientists examined one of the enlarged faraway galaxies, they discovered that a point of light coincided with one of the ripples, and the brightness of the point of light was multiplied by a thousandfold or more.
Mr. Welch described the galaxy as “kind of spread out into this long crescent-shaped arc.” “Then there’s the star, which is simply one component of it.”
Objects that are farther away are going away at a quicker rate because the universe is expanding. Because of this, the frequency of light is shifted to longer wavelengths. Mr. Welch and his colleagues discovered a star with a red shift of 6.2, which is far greater than the previous record-holder for the most distant single star. The star was discovered by Mr. Welch and his colleagues. The star in question, discovered in 2018, had a red shift of 1.5, which corresponded to a time when the universe was around four billion years old.
The new star was given the name Earendel, which is an Old English word that means “dawn star.” If it is a single star, the scientists believe it to be a massive one with a mass around 50 times that of our sun. It might also be a system of two or more stars, as in the case of the Sun.
Because the alignment of Earendel and the galaxy cluster will last for years, Earendel will be one of the targets for the newly launched James Webb Space Telescope during its first year of observations. The James Webb Space Telescope has a larger mirror than the Hubble Space Telescope and gathers light at longer infrared wavelengths than the Hubble Space Telescope.
Because of the Webb observations, it will be possible to quantify brightness across a wide range of wavelengths. This will assist astronomers in determining the temperature of the star. According to Mr. Welch, “we actually need that spectrum in order to declare with kind of total confidence that this is a star as opposed to some other type of object.”
Mr. Welch said that later, more thorough observations by Webb might be used to determine the makeup of Earendel’s constituents. In order to accommodate this, it is believed that the earliest stars would have lower quantities of heavier elements, which are produced through fusion events inside stars and in the explosions of dying stars. The prevailing view is that since there were less heavy elements in the early universe, more of the early stars should have been large and luminous.
In the words of Steven Finkelstein, an astronomer at the University of Texas at Austin who was not involved in the study, Earendel seems to be “quite hot and fairly enormous.”
However, one star alone would not be sufficient evidence to support the hypothesis of larger stars in the early cosmos. According to Dr. Finkelstein, the evidence “clearly supports that.” The evidence that more massive stars are the norm in the distant cosmos would get stronger and stronger if you started building up a big number of them, and many of them seemed to be rather enormous.
The Webb telescope should also be able to detect additional distant magnified stars, such as Earendel, however it is unclear how many of these stars are coincidentally aligned with a gravitational lens at any one time. Perhaps even certain stars with a red shift between 10 and 20, which correspond to a time period between 100 million and 500 million years after the Big Bang, will be visible to it.
