Recent observations from the James Webb Space Telescope (JWST) are challenging long-held beliefs about the universe's formation. Since its launch in December 2021, JWST has identified some of the oldest and most distant galaxies, existing just 300 million years after the Big Bang.
These ancient galaxies appear much brighter than expected, suggesting they contain more stars and mass than previously thought. This rapid formation raises questions about the current cosmological models that describe the universe's evolution, particularly the ΛCDM model, which includes dark matter and dark energy as key components.
JWST's advanced imaging and spectroscopy capabilities have allowed scientists to analyze galaxies with redshifts between 10 and 15, indicating they formed between 200 and 500 million years post-Big Bang. These small galaxies, about 100 parsecs in diameter, are forming stars at a rate comparable to our Milky Way, but will double their stellar content in just 100 million years.
The unexpected brightness of these early galaxies suggests they matured faster than current models predict. This has led researchers to reconsider the efficiency of star formation and the impact of feedback processes like supernovae and black holes in regulating star creation.
Some theories propose that early star formation may have been more explosive than previously thought, while others suggest changes in the physics of galaxy formation or modifications to cosmological theories could be necessary. The JWST has already identified the most distant galaxy, JADES-GS-z14-0, but more observations are needed to fully understand these ancient structures.
As JWST continues its mission, it is expected to provide deeper insights into the early universe, potentially reshaping our understanding of cosmic history and the formation of galaxies.