Only recently, on the 22nd of September, the Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) discovered something quite odd - six dead, empty galaxies had run out of cold hydrogen gas, an element that serves as the very basis for star formation. In our current period in the age of the universe, galaxies are forming lots of stars. The detection of these six apparently empty galaxies that have seemed to have been depleted of their fuel source still remain a peculiar sight to scientists conducting the program.
The study for these early, dead galaxies were part of the REQUIEM project. The team uses the natural immense gravity of these distant galaxies as a tool to help with observations. The immense gravity of these galaxy clusters warps the space around it, allowing any light rays passing through it to bend and magnify. This causes astronomers to see details that would have otherwise been impossible to detect.
According to some of the scientists running the project, the six dead galaxies had lived very fast and fierce lives, creating stars in an incredibly short amount of time. Why these galaxies then ceased star formation later on, is still a mystery.
There are several possible explanations: one is that there could have been a supermassive black hole in the center of the galaxy, which could have heated up the interstellar gases until they are no longer dense enough to form stars. Alternatively, these gases could have been expelled and somehow prevented from accreting back into the galaxy. Perhaps there are no interstellar gas clouds left to form any stars in the galaxy as they all have already been ‘used up’. Either way, scientists are still exploring the mysteries of these six empty galaxies and what could have caused them to end like this.
I have always had a particular fascination with space and the cosmos, and I feel that there is so much more to learn about our universe than we already know. Even with our latest technologies and extremely precise measuring equipment, scientists are still discovering new things every day. What is your take on these dead, empty galaxies? What do you think could have happened to them?
Images from NASA's Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA)
Citations:
NASA/Goddard Space Flight Center. “Hubble Finds Early, Massive Galaxies Running on Empty.” ScienceDaily, ScienceDaily, 22 Sept. 2021, https://www.sciencedaily.com/releases/2021/09/210922121920.htm.
Jenner, Lynn. “Hubble Finds Early, Massive Galaxies Running on Empty.” NASA, NASA, 17 Sept. 2021, https://www.nasa.gov/feature/goddard/2021/hubble-finds-early-massive-galaxies-running-on-empty.
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