The James Webb Space Telescope Continue to push the boundaries of our knowledge. On November 17, it was confirmed that this orbiting observatory had captured two of the oldest galaxies ever seen. This discovery has scientists captivated – and somewhat baffled – why such a thing exists cosmic structures It can change already existing models of the evolution of the universe.
According to the article reporting the finding, which was published in the journal Astrophysical Journal Lettersdetermined that the images taken of both galaxies correspond to 450 million and 350 million years after the Big Bang, the explosion indicating the origin of the universe, 13.8 billion years ago.
So far, all good, they are very old. But something does not add up: unlike other galaxies Found in the early universe-This is very bright.
Of the two galaxies found by James Webb, Z12 is the farthest and the oldest. Image: NASA/ESA
In a NASA news conference call, the study authors noted that this extreme brightness points to two unusual possibilities.
The end of the dark ages
One possible explanation is that both galaxies are just as massive and full of stars as current galaxies. However, for this they only had to start forming After 100 million years the great explosion.
This is a very big problem, because cosmology proves it The dark age of the universea time when there was only dissolved gas with no possibility of star formation or reflection of light, lasted until 200 million years after the birth of the universe.
The Dark Ages began 370,000 years after the Big Bang and lasted about 200 million years. Photo: C.-A. Faucher-Giguere et al. / Sciences
Therefore, the formation of galaxies in such a distant era forces cosmologists to delay the date of the end of the Dark Ages and, accordingly, to rethink the evolution of the universe.
Specifically, according to this hypothesis, the first star lights appeared a hundred million times earlier than previously thought.
All-star moms
Another possibility is that these galaxies were formed by previously unseen stars: Population Stars III.
To date, the observed stars are roughly divided into metal-rich (Community I) and metal-poor (Community II). However, astronomers assume that the first generation of stars arose when The universe was devoid of heavy elements. Therefore, they suggested the existence of a third population.
These stars will consist almost entirely of helium and hydrogen. Likewise, it is estimated that it must reach a very high temperature and, therefore, a brilliant luster.
Illustration of the first stars in the universe (Population III). Image: Kavli Foundation
In this sense, the galaxies formed by group III stars do not have to be very massive to justify the brightness noted by James Webb, so it is possible that they formed later.
The search is just beginning
These and other ancient – and very distant – galaxies were discovered from data collected in the early days of the space telescope’s operation.
In addition to Webb’s speed in capturing the oldest galaxies, astronomers suggest he did so by exploring on his own A very small strip of sky.
“It’s a bit surprising that there are so many of those that formed so early,” said astrophysicist Jeyhan Kartaltepe of the Rochester Institute of Technology.
“We’re seeing very bright and light galaxies at this early time, and we’re not really sure what’s going on here,” added Garth Illingworth of the University of California, Santa Cruz.
To determine the correct hypothesis for the latest discovery, astronomers hope to use spectrometer by James Webb, which analyzes light and thus makes it possible to accurately determine the distance and composition of galaxies.
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