We Finally Know Why Some of The Earliest Galaxies Stopped Forming 12 Billion Years Ago - ScienceAlert

After all, they were born with rich supplies of cold hydrogen gas, exactly the fuel needed to continue star formation.

But new observations have revealed "quenched" galaxies that have shut off star formation.

Those galaxies were targeted because they were known to be "quenched", with little to no star formation.

"We still have so much to learn about why the most massive galaxies formed so early in the Universe and why they shut down their star formation when so much cold gas was readily available to them," said Whitaker

"The mere fact that these massive beasts of the cosmos formed 100 billion stars within about a billion years and then suddenly shut down their star formation is a mystery we would all love to solve, and REQUIEM has provided the first clue."