It heats up the gas too much, and to collapse and form stars, gas needs to be cold. But sometimes, it injects too much energy into its galaxy or galaxy cluster, and that chokes off star formation. Sometimes all that feedback drives star formation. Jets are the primary way that black holes interact with the surrounding medium, pumping matter back out of their accretion disks into their surroundings. Different black holes drive different types of feedback, and some feedback drives higher rates of star formation. The matter is the galaxy's gas, and different galaxies have different gas environments.īlack hole feedback plays a major role in Garofalo's work. Some AGN emit jets, and they're dependent on the nature of the matter accreting onto the hole. It starts with a black hole merger that's likely to lead to active galactic nuclei (AGN,) which is the term for a supermassive black hole (SMBH) at the center of a galaxy that is accreting enough matter to shine brightly. Garofalo claims that advanced life peaked billions of years ago, all because of the direct connection between mergers, black holes, star formation, and the planets that form around those stars. Garofalo has researched black holes extensively, and this paper leans heavily on his research and the work of others in the same field. Black hole feedback affects star formation in galaxies, but the effect varies. "Our understanding of the processes that determine where and when star formation peaks in the universe has matured significantly, to the point where we can begin to explore more broadly the question of intelligence across space and time," Garofalo writes. Garofalo starts with black holes, feedback, and star formation. Garofalo's effort extends beyond the Milky Way into the universe. It's a probabilistic equation that tries to calculate the number of intelligent and communicative civilizations there are in the Milky Way. The Drake Equation tries to give form to our ponderings about other intelligent civilizations. "The link between black holes and star formation allows us to draw a connection between black holes and the places and times when extraterrestrial intelligences (ETIs) had a greater chance of emerging," Garofalo writes. Whether it does or not depends on the environment and whether the SMBH is in a gas-sparse or a gas-rich environment. Garofalo explains how black hole feedback can either drive or suppress star formation. ![]() Garofalo is the sole author, and the paper hasn't been peer-reviewed yet. The paper is "Advanced Life Peaked Billions of Years Ago According to Black Holes." It's available on the arXiv preprint server and soon to be published in the journal Galaxies. Garofalo researches the physics of black holes, and in a new paper, he explains how black holes could affect the existence of advanced life. Because, the a priori reasoning tells us, individual planets are the key to finding life.īut what about a more wide-angle view of habitability and, especially, other advanced life? Is combing through individual planets the way to find other life? Or are certain galaxies themselves more likely to host advanced life, which can take billions of years to evolve? Do the black holes in galaxies affect the likelihood of advanced life?ĭavid Garofalo is an associate professor of physics at Kennesaw State University in Georgia. That's a simple definition of habitability, but it's useful for sorting through the thousands of exoplanets we've discovered and the untold millions more waiting to be discovered. We live in an era of exoplanet discoveries, and astronomers are busy searching for planets that have a possibility of being habitable, i.e., they have liquid surface water. They're all related to the Great Question: Are We Alone? We ask these questions as if humanity woke up on this planet, looked around the neighborhood, and wondered where everyone else was. ![]() ![]() ![]() All three are different ways that humanity grapples with its situation. Universe Today readers are familiar with SETI, the Drake Equation, and the Fermi Paradox. A new study focusing on black holes and their powerful effect on star formation suggests that we, as advanced life, might be relics from a bygone age in the universe.
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