Wow! James Webb Space Telescope shows galaxies may have formed far earlier than thought
The first galaxies may have formed far earlier than previously thought, according to observations from the James Webb Space Telescope that are reshaping astronomers' understanding of the early universe.
Researchers using the powerful observatory have now published papers in the journal Astrophysical Journal Letters, documenting two exceptionally bright, exceptionally distant galaxies, based on data gathered within the first few days of Webb going operational in July.
Their extreme luminosity points to two intriguing possibilities, astronomers on a NASA press call said Thursday.
The first is that these galaxies are very massive, with lots of low-mass stars like galaxies today, and had to start forming 100 million years after the Big Bang which occurred 13.8 billion years ago.
That is 100 million years earlier than the currently held end of the so-called cosmic dark age, when the universe contained only gas and dark matter.
A second possibility is that they are made up of "Population III" stars, which have never been observed but are theorized to have been made of only helium and hydrogen, before heavier elements existed.
Because these stars burned so brightly at extreme temperatures, galaxies made of them would not need to be as massive to account for the brightness seen by Webb, and could have started forming later.
"We are seeing such bright, such luminous galaxies at this early time, that we're really uncertain about what is happening here," Garth Illingworth of the University of California at Santa Cruz told reporters.
The galaxies' rapid discovery also defied expectations that Webb would need to survey a much larger volume of space to find such galaxies.
"It's sort of a bit of a surprise that there are so many that formed so
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