We finally know what invalidates the darkness of the early universe.
According to Hubble and James Webb Space Telescope, the origin of free-flying photons at early cosmic dawn was a dwarf galaxy scattered to lifespan, clearing out fog that filled the fuzzy hydrogen that filled the interlayered space. The paper on the research was published in February 2024.
“This discovery reveals the key role that supervariety galaxies play in the evolution of the early universe,” said Iryna Chemerynska, an astrophysicist at the Institute of Astronomy.
“The ionized photons they produce convert neutral hydrogen into ionized plasma during cosmic ionization. It highlights the importance of understanding low-mass galaxies in shaping the history of the universe.”
At the beginning of the universe, within minutes of the Big Bang, the space was filled with heat-filled ionized plasma. The light there won't penetrate this fog. Photons will simply be scattered in floating free electrons, effectively making the universe dark.
As the universe cooled, about 300,000 years later, protons and electrons began to gather together to form neutral hydrogen (and a little helium).
Most wavelengths of light can penetrate this neutral medium, but there is little way for light sources to produce it. But from this hydrogen and helium, the first batch of stars were born.
Those first stars convey enough radiation to strip electrons from their nucleus and restore gas. However, at this point, the universe has expanded so much that the gas has spread and cannot prevent light from being emitted.
About 1 billion years after the Big Bang, the end of the period known as the dawn of the universe, the universe has been fully developed. ta-da! The lights are on.
But because there is so much darkness in the dawn of the universe, and because it is so dim and distance across time and space, it is hard to see what is there.
Scientists believe that the sources responsible for most cleaning must be powerful – for example, huge black holes produce blazing light, for example, in huge galaxies with star formations (baby stars produce a lot of ultraviolet light).
JWST is designed partly to peek at the dawn of the universe and try to see what lurks there. This is very successful, revealing various surprises during this critical period of the formation of our universe. Surprisingly, the telescope observations now show that dwarf galaxies are key players in ionization.
An international team led by astrophysicist Hakim Atek of the Institute of Astrophysics turned to JWST data on a cluster of galaxies called Abell 2744, and was supported by Hubble.
Abell 2744 is so dense that space and time bypass it, forming a cosmic lens. Any distant light transmitted to us through this space-time will amplify. This allows researchers to see small dwarf galaxies near the dawn of the universe.
They then used JWST to obtain detailed spectra of these tiny galaxies. Their analysis shows that these dwarf galaxies are not only the most abundant galaxy types in the early universe, but are much better than expected.
In fact, the team's research shows that large galaxies with more than 100 to 1 have a collective output of four times the ionizing radiation that is usually assumed to be larger galaxies.
“These powerful powers of these universes collectively emit enough energy to get the job done,” Atek said.
“Although their size is small, these low-mass galaxies are prolific producers of energy radiation, during which time their abundance is so great that their collective influence can change the state of the universe.”
This is the best evidence of the power of the motor so far, but there is more work to be done. The researchers looked at a small spot in the sky. They need to make sure that their samples are not only anomalous clusters of dwarf galaxies, but also representative samples of the entire population at dawn of the universe.
They intend to study more sky cosmic lens regions to obtain a wider sample of early galactic populations. However, for this sample, the results are incredible. As long as we know this, scientists have been chasing the answer to ionization. We are on the verge of finally blowing away the fog.
“We have now entered the unknown territory with JWST,” said Themiya Nanayakkara, an astrophysicist at the Swinburne Technical University in Australia.
“This work opens up more exciting questions that we need to answer to map the evolutionary history we started.”
The study has been published in nature.
The version of this article was originally published in March 2024.
