Many of us will never understand the fact that scientists can actually look back in time.
The power of telescopes allows us to study phenomena that happened billions of years ago, and even peer into the dawn of creation itself.
Now astrophysicists have solved a great mystery at the heart of our universe’s birth, when everything was shrouded in a thick fog.
In four separate papers published in (or accepted in) The Astrophysical Journalscientists from the Massachusetts Institute of Technology, Japan’s Nagoya University, ETH Zurich and the University of Groningen in the Netherlands have shared some stunning insights into the period known as the Age of Reionization.
Relatively little is known about this epoch, during which the dense fog engulfing the universe gradually dissipated, allowing the stars and galaxies to shine.
However, new observations made using the James Webb Space Telescope (JWST) are beginning to pull back the curtain on all this.
Now scientists have finally figured out why, one billion years after the Big Bang, this thick fog finally dissipated.
First, what exactly is the age of reionization?
For the first billion years after the Big Bang, space was filled with a dense fog of ionized gas that was impervious to light.
As the gas began to cool, the protons and electrons began to combine to form mostly neutral hydrogen atoms and some helium.
These clumps of neutral hydrogen are then thought to have begun to form stars clustered into galaxies.
This process reionizes the gas, but since space has expanded by this point, the newly ionized hydrogen is diffuse enough to allow light to flow through it, as Learned signalnotes.
A few million years later, the universe became the transparent space we are now familiar with.
To explain, here’s what these four new papers reveal about why the cosmos just got so much clearer.
JWST returned extremely detailed images of galaxies that existed when the universe was only 900 million years oldNASA/Space Telescope Science Institute (STScI)
Paper 1
IN first studyresearchers from the University of Groningen revealed that they have found important evidence of star formation during the age of reionization.
They discovered a specific wavelength of hydrogen, called hydrogen alpha, which forms at the birth of a star and shoots out massive amounts of ionizing ultraviolet radiation.
Until now, no one was sure what produced all the ultraviolet light that appeared during the age of reionization.
But thanks to the discovery of hydrogen alpha, the team of astronomers in Groningen found that star formation has a “significant role in the reionization process”.
Paper 2
Another paperled by Japanese astrophysicist Daichi Kashino, added galaxies to the mix.
According to Caschino and his international team, the reionization occurred in “bubbles” around the many newly formed galaxies.
They used data from JWST to pinpoint these pockets and precisely measure them, finding them to be 2 million light-years in radius around the small galaxies.
Over the next hundred million years, the bubbles get bigger and bigger, eventually merging and making the entire universe transparent, according to a paper published by NASA.
Galaxies have been found to be largely responsible for the ‘clear’ conditions found in much of the universe todayNASA, ESA, CSA, Joyce Kang (STScI)
Paper 3
A third group by researchers led by ETH Zurich astrophysicist Jorryt Matthee analyzed the characteristics of these bubbles and found that the early galaxies they contained were hot, low in metals and dust, and very active.
He said they were “more chaotic” than those in the nearby universe, adding: “Webb shows that they were actively forming stars and must have fired a lot of supernovae. They had quite an adventurous youth!’
Paper 4
A fourth paperled by MIT cosmologist Anna-Christina Eilers, focused its attention on the quasar galaxy at the center of the JWST observations.
This quasar, according to NASA, is an “extremely luminous active supermassive black hole that acts like a giant flashlight.”
Eilers and her team used data from the telescope to confirm that the black hole is the most massive currently known in the early universe, weighing 10 billion times the mass of the Sun.
“We still can’t explain how quasars managed to get so big so early in the history of the universe,” she said. “That’s another puzzle to solve!”
Conclusion
Well done if you survived to the end – it’s all pretty tough. But the key point here is that before JWST, no one knew for sure what caused reionization.
Now, thanks to the mighty Golden Eye Telescope, one of the great mysteries behind the birth of creation has finally been solved.
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