Breakthrough Study Reveals Dwarf Galaxies as Source of Universe’s First Light

Scientists say that the universe began in very dark conditions and then the first light appeared. So where does the light come from?

A new study published in Nature in February 2024 succeeded in revealing where the first light in outer space came from. According to a study titled “Most of the Photons Reflected in the Universe from Dwarf Galaxies” by Hakim Atek and colleagues, dwarf galaxies are known to play an important role in creating light.

“The origin of photons or light particles that first spread freely in outer space came from small galaxies called “dwarf galaxies,” said astronomer and researcher from the Institut d’Astrophysique de Paris, Iryna Chemerynska, as which was named from. Science Alert.

According to Chemerynska, this dwarf galaxy plays a role in emitting light that helps clear the hydrogen cloud that filled space at the beginning of the universe’s creation. This hydrogen vapor is initially opaque to light.

“Dwarf galaxies produce ionizing photons that turn neutral hydrogen into ionized plasma through the process of cosmic reionization,” Chemerynska explained.

“This discovery reveals the important role played by ultra-thin galaxies in the evolution of the early universe,” he said.

The process of creating the first light in the universe

Chemerynska explained that after the Big Bang event that created the universe, space was filled with hot and dense plasma fog. The large number of ionized particles in the form of free electrons and protons in space means that light cannot penetrate the smoke.

About 300,000 years later, when the universe began to cool, protons and electrons in space began to combine and form neutral hydrogen gas and some helium. From this hydrogen and helium gas, the first stars in dwarf galaxies were formed.

These first stars then emit radiation that helps ionize hydrogen gas, and clears the smoke so that light can emerge and spread through the universe.

“About 1 billion years after the Big Bang, the end of the period known as the cosmic day, the Universe completely revived. Ta-da! The lights came on,” explained Chemerynska.

How do scientists study light in the universe?

In their study, the researchers used the James Webb Space Telescope (JWST) to observe space. Through this telescope, they discovered that dwarf galaxies are one of the keys to reionization that then made light appear.

“Despite their small size, these galaxies are prolific emitters of energetic radiation, and their abundance in this period is so great that their collective effect could change the state of the entire Universe, “said Hakim Atek, astronomer and co-researcher from the Institut. d’Astrophysique de Paris.

“These cosmic powerhouses together emit more than enough energy to get the job done,” he continued.

Researchers hope that their new study will provide new knowledge about the early evolutionary history of the universe.

“We have now entered uncharted territory with JWST,” said astronomer Themiya Narayakkara of Swinburne University of Technology in Australia.

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