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Galaxies are a bit like pets: you have to give them their food regularly, over a long period of time. Plunging a year of kibble in a giant bowl for your puppy could help your pet gain weight, but that would not be good for the pet in the long run, especially once the food source has been exhausted early.
Gives a galaxy all its fuel in the first years of its life, and something similar happens. The object becomes what astronomers call a "starburst" galaxy, which engulfs its fuel too quickly, quickly turning it into stars. And star-shaped galaxies generally fail to form stable old galaxies like the Milky Way. They die young.
Some galaxies, however, have a defense mechanism against this fate: the galactic wind. Streams of molecules escape from these galaxies, escape into the universe or gravitate around the Earth as halos of matter, material that can then rain in the galaxy and fuel surges of formation of healthier stars. The wind slows the growth of a galaxy, giving it time to methodically reach an adult size. [Interstellar Space Travel: 7 Futuristic Spacecraft to Explore the Cosmos]
That's all according to an article published today (September 6) in the journal Science. And for the first time, the authors reported, they saw this galactic wind in action in the primitive universe. Thanks to a bit of luck and careful consideration, the researchers observed that the galactic wind was flowing from a galaxy 12 billion light-years away from Earth and named SPT2319-55. Given how long it takes light to reach Earth from this distance, it means that the wind that the scientists observed has passed from the galaxy only a billion years after the Big Bang, in childhood of our universe.
"Observing winds in the distant universe is difficult," the researchers wrote. The light of these old galaxies is weak. In addition, the fingerprints of this wind, observed as they move, can be drowned by other signals from the process being assembled galaxies, wrote the researchers.
To see the signature of the stellar wind, the researchers relied on a helping hand from a second galaxy not so far away. Massive objects such as galaxies have such gravity that they can bend and form light lenses. And in this case, such a gravitational lens gave SPT2319-55 a much larger Earth appearance, so scientists from Atacama's large millimeter / submillimeter network in Chile could observe the galaxy with much more details.
The wind, which researchers have detected through spikes in the presence of a molecule called hydroxyl (OH), exploded out of the galaxy at nearly 500 miles per second (800 kilometers per second), wrote the authors.
But SPT2319-55 is already a star-shaped galaxy, and it is not clear whether this wind will be enough to save it from its own appetites and allow it to age.
"Our results show that [the wind]is acting to disrupt and eliminate the molecular gas in SPT2319-55, "the researchers wrote in the study, and will likely suppress the rapid formation of stars in this galaxy. [million years]. If this is enough to smother the formation of stars on a more permanent basis, it is less clear.
SPT2319-55 could have so much dark matter around it that the wind can not save the galaxy, the researchers wrote. When all this expelled wind tries to fall back into the galaxy to form new stars, dark matter could topple it, preventing it from accumulating, the authors wrote. In this case, despite its wind, the SPT2319-55 will probably die young, victim of its own greed and its mass, condemned despite its protective winds.
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