Five galaxies have been detected by the
James Webb Space Telescope (JWST). These galaxies are 200 million years after the
Big Bang, making them the earliest galaxies ever discovered. There is speculation that there may be many more.
Located 13.6 billion light-years away, formed just 200 million years after the Big Bang, these five galaxies are the farthest galaxies ever discovered and likely among the first to form in the ancient
Universe.
If the observations are confirmed, the ancient galaxies will give astronomers a chance to test existing theories of galaxy formation and provide unique insights into how matter first collapsed in space.
The researchers published their results on Nov. 26 in the arXiv preprint database, so they have not yet been peer-reviewed.
"According to the standard structure formation paradigm, the same primordial fluctuations that produced hot and cold spots in the cosmic microwave background (CMB) will eventually grow, collapse, and form the first galaxies during the cosmic dawn, ushering in the era of the first light," the researchers wrote in their paper.
"These first galaxies remained beyond our observational reach for decades," they add. "JWST, however, has changed this situation." Based on past assumptions by cosmologists, the first clusters of stars began to merge and form galaxies just a few hundred million years after the Big Bang.
Then, after only 1-2 billion years of the Universe's life, according to current theories, these early protogalaxies reached "adolescence" - forming into dwarf galaxies that devoured each other to then grow into ones like the one Earth is in.
But determining the exact timing of this process and the speed at which the earliest stages occurred is difficult because the light from these galaxies is very faint and the expansion of the Universe has dramatically stretched (or shifted) their wavelengths in the infrared spectrum.
Unlike its predecessor, the
Hubble space telescope, JWST can detect light in the infrared spectrum, giving the telescope access to the first stages of the Universe's evolution. However, the light coming from the earliest epochs of our Universe is still too dim to be detected independently.
To get around this problem, researchers making new observations as part of the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) project took advantage of a phenomenon known as gravitational lensing (an effect that occurs when light emitted by one galaxy passes through another) to magnify the distant light from these early galaxies.
As described by
Einstein in his general theory of relativity, gravity is the warping and distortion of spacetime in the presence of matter and energy. This warped space, in turn, dictates how energy and matter move.
This means that even though light travels in a straight line, it can be bent and its intensity increased by gravity. In this case, the detected galaxy Abell S1063 lies between the region chosen for the study and the Solar System, focusing the light of an early galaxy so that it can be seen in telescopes.
By pointing JWST at this region of curved space and slowly collecting the light shining through, astronomers pushed the telescope's capabilities to the limit, catching the first faint reflections of early galaxies.
If further research is confirmed, these candidate galaxies would appear to be about 90 million years younger than the earliest confirmed galaxy, JADES-GS-z14-0, making them among the earliest that could have ever formed. And the fact that they were all detected in the same region of the sky suggests there could be many more.
How did these galaxies grow so fast? Answers to this cosmic mystery remain elusive, but they are unlikely to affect the current understanding of cosmology. Instead, astronomers are coming up with explanations that include the earlier-than-expected appearance of giant
black holes, feedback from supernova explosions, or even the influence of dark energy to explain the rapid formation of stars within them.