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Cause Of Galactic Death: Strangulation
As murder mysteries go, it’s a big one: how do galaxies die and what kills them? A new study, published today in the journal Nature, has found that the primary cause of galactic death is strangulation, which occurs after galaxies are cut off from the raw materials needed to make new stars.
Researchers from the University of Cambridge and the Royal Observatory Edinburgh have found that levels of metals contained in dead galaxies provide key ‘fingerprints’, making it possible to determine the cause of death.
There are two types of galaxies in the Universe: roughly half are ‘alive’ galaxies which produce stars, and the other half are ‘dead’ ones which don’t. Alive galaxies such as our own Milky Way are rich in the cold gas – mostly hydrogen – needed to produce new stars, while dead galaxies have very low supplies. What had been unknown is what’s responsible for killing the dead ones.
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Water Was Plentiful In The Early Universe
Astronomers have long held that water — two hydrogen atoms and an oxygen atom — was a relative latecomer to the universe. They believed that any element heavier than helium had to have been formed in the cores of stars and not by the Big Bang itself. Since the earliest stars would have taken some time to form, mature, and die, it was presumed that it took billions of years for oxygen atoms to disperse throughout the universe and attach to hydrogen to produce the first interstellar “water.”
New research poised for publication in Astrophysical Journal Letters by Tel Aviv University and Harvard University researchers reveals that the universe’s first reservoirs of water may have formed much earlier than previously thought — less than a billion years after the Big Bang, when the universe was only 5 percent of its current age. According to the study, led by PhD student Shmuel Bialy and his advisor Prof. Amiel Sternberg of the Department of Astrophysics at TAU’s School of Physics and Astronomy, in collaboration with Prof. Avi Loeb of Harvard’s Astronomy Department, the timing of the formation of water in the universe bears important implications for the question of when life itself originated.