The James Webb Space Observatory has made a new and unexpected discovery: it has detected light from a galaxy in the early universe that, according to all known laws, should not have reached its sensors. The discovery provides new insights into the early evolution of stars and galaxies in the universe, which should have a critical impact on our understanding of these processes.
Image source: NASA
The work published in the journal Nature is devoted to the analysis of the galaxy JADES-GS-z13-1. This object was discovered by Webb 330 million years after the Big Bang. This was the time when visible light (from the first stars and galaxies) was still having difficulty spreading throughout the Universe. There were still about 700 million years left before the emergence of a transparent Universe with extremely rarefied molecular hydrogen. The signal from the galaxy JADES-GS-z13-1 recorded by Webb would be characteristic of a later period of the Universe’s evolution, and its appearance, as well as the very fact of its detection at such an early stage of the universe, baffled scientists.
We are talking about the detection of the Lyman-alpha line in the galaxy JADES-GS-z13-1 – this is a spectral line of ultraviolet radiation of hydrogen with a wavelength of 121.6 nanometers. It occurs when an electron in a hydrogen atom moves from the first excited level to the ground, emitting a photon. In the early Universe, ultraviolet photons of this line were absorbed by neutral hydrogen, which created characteristic traces in the emission spectrum of distant objects. Scientists did not expect to see this line in a galaxy that existed 330 million years after the Big Bang. It could only be detected in a bubble of transparency with a diameter of 650 thousand light years. However, Webb recorded a burst of this light after 13.4 billion years! This became a mystery for researchers, who do not yet have a clear answer to this phenomenon.
There are two possible explanations for the observed phenomenon. Firstly, it may be a consequence of the extreme activity of the black hole in the galaxy. Secondly, the distant galaxy may contain an abnormally large number of supermassive stars, each of which is 100-300 times the mass of the Sun. However, both hypotheses do not yet have sufficient evidence for one of them to be considered definitive. Scientists will continue to observe this distant galaxy and hope to discover other similar objects. This will be an invaluable contribution to understanding the processes that occurred in the early Universe, from where clear signals reach us with great difficulty.