James Webb Space Telescope Reveals Mystery of the Universe’s Reionization Era

JAKARTA – The James Webb Space Telescope owned by NASA and its international partners has unraveled the mystery of when in the early universe, the gas between stars and galaxies was opaque, where the energetic light of stars could not penetrate.

However, one billion years after the Big Bang, gas became completely transparent. The Webb telescope found that the galactic stars emit enough light to heat and ionize the gas around them.

A team of scientists led by Simon Lilly of ETH Zürich in Switzerland found new insights into a time period known as the Reionization Era, when the universe underwent dramatic changes.

After the Big Bang, the gas in the universe became very hot and dense. Over hundreds of millions of years, the gas cooled. Then, the universe reaches repetition.

The gas again became hot and ionized, possibly due to early star formation in the galaxy and became transparent over millions of years. Scientists have been looking for definite evidence to explain this transformation for a long time. The new research results effectively pull back the curtain on the end of that reionization period.

“Webb has not only clearly demonstrated that this transparent region is found around galaxies, we have also measured how large it is,” said the team’s first paper lead author, Daichi Kashino of the University of Nagoya, Japan, quoted from NASA’s website, Tuesday, June 13. .

“With the Webb data, we see galaxies re-ionizing the gas around them,” he added.

This area of ​​transparent gas is huge compared to galaxies. Webb Telescope data show these relatively small galaxies are driving reionization, clearing large regions of space around them.

Over the next hundred million years, the transparent bubble continued to grow larger and larger, eventually converging and causing the entire universe to become transparent.

Lilly’s team deliberately targeted a time before the end of the Reionization Era, when the universe was less clear and less opaque containing gaseous patches in various states.

Scientists point the Webb Telescope toward quasars, active supermassive black holes that are extremely bright and act like huge flashlights, highlighting gas between the quasar and the telescope.

As the quasar’s light travels toward the telescope through different swaths of gas, it is absorbed by the opaque gas or moves freely through the transparent gas.

Next, the scientists’ breakthrough results coupled Webb Telescope data to observations of the central quasar from the WM Keck Observatory in Hawaii, the European Southern Observatory’s Very Large Telescope and the Magellan Telescope at Las Campanas Observatory, both in Chile.

“By illuminating the gas along our line of sight, quasars provide us with extensive information about the composition and state of the gas,” explained co-author of the paper Anna-Christina Eilers of MIT in Cambridge, Massachusetts.

Later, scientists used the Webb Telescope to identify galaxies near this line of sight and showed that galaxies are generally surrounded by a transparent region with a radius of about 2 million light years.

In other words, the Webb Telescope witnessed galaxies clearing the space around them at the end of the Reionization Era.

To give you an idea, the area that these galaxies have cleared is roughly the distance between the Milky Way galaxy and its closest neighbor, Andromeda.

Until now, scientists had no definitive proof of what caused reionization, until Webb Telescope data showed it, they weren’t sure exactly what caused it.

Throughout the study, Eilers used Webb Telescope data to confirm the black hole in the quasar at the center of the field was the most massive known today in the early universe, weighing 10 billion times the mass of the Sun.

“We still can’t explain how quasars grew so large early in the history of the universe. That’s another puzzle to solve!” said Eilers.

They, scientists in the future will soon explore the galaxy in five additional fields, each anchored by a central quasar.

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