Are some galaxies more hospitable to life than others?

_{Denyse O'Leary

October 10, 2019

Extraterrestrial life, Intelligent Design}

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An organized swirl of blue stars and brown dust streaks — dwarf spiral galaxy/NASA

Some researchers are trying to narrow it down:

Large spiral galaxies are one galaxy type that researchers think may be good for developing life. Our own planet is the only known example of life arising in such a galaxy, but spirals pack relatively high amounts of the heavy elements needed to form rocky planets.
However, life in a spiral galaxy can have its downsides, too. These galaxies form new stars more actively and have more dangerous cosmic events, like supernova explosions, compared to other galaxies. Those kinds of disasters can spew harmful radiation into nearby space and potentially destroy planets’ biospheres.
So, perhaps galaxies with less active star formation, and fewer cosmic explosions, might be calmer, safer places that allow planets more time to develop life.
Erika K. Carlson, “Which Galaxies are Best Suited for the Evolution of Alien Life?” at Discover Magazine

When the researchers tested the thesis by studying 100,000 simulated galaxies, they found that small or dwarf galaxies with comparatively abundant heavy elements offered the best chance.

Some of us would settle for a single fossil bacterium on Mars and forget all the theories.

See also: Once Upon A Time, Venus (Might Have) Had Life, Say Researchers

Comments

as to this claim,
So, perhaps galaxies with less active star formation, and fewer cosmic explosions, might be calmer, safer places that allow planets more time to develop life.
Actually a galaxy with 'just right' active star formation is a necessary prerequisite for life. As well a galaxy must have the right 'spiral shape' and a galaxy can also be neither too small, nor too large, to host life:
Our Universe (4): The Fine Tuning in a Galaxy… - Mark Goodnight - October 27, 2016 Excerpt: Both our galaxy and the location of our solar system within the galaxy is also fine-tuned for advanced life to exist. There are several factors to consider. The galaxy that our solar system resides in is called the Milky Way, and it is of a shape that is called a barred spiral galaxy. In regards to the shape of the galaxy, J Warner Wallace, in his book God’s Crime Scene: A Cold-Case Detective Examines the Evidence for a Divinely Created Universe, sums it up this way: THE SHAPE OF THE MILKY WAY IS FAVORABLE TO LIFE "The Milky Way galaxy is an elegant spiral, while the vast majority of galaxies (approximately 95% percent of them) are elliptical or irregular. This spiral shape makes a difference. If our galaxy were larger and irregular (rather than spiral), its nucleus would release destructive radiation (and matter) harmful to the existence of life. On the other hand, dwarf elliptical galaxies are metal-poor (metals are heavy elements) so they are unlikely candidates for life. As it is, the spiral shape encourages the early formation of stars before this formation can be threatened by the presence of heavy elements in the interstellar environment." He then quotes Astrophysicist Hugh Ross in his footnotes: "In elliptical galaxies star formation ceases before the interstellar medium becomes enriched enough with heavy elements…The problem with large irregular galaxies is they have active nuclei. These nuclei spew out life-destroying radiation and material. Meanwhile, most small irregular galaxies have insufficient quantities of the heavy elements essential for life." Another way that Hugh Ross says this is that if the galaxy type is too elliptical, the star formation would cease before sufficient heavy element build-up for life chemistry. And that if the galaxy type is too irregular, the radiation exposure on occasion would be too severe and heavy elements for life chemistry would not be available. In addition to the shape of the galaxy, we also have to consider is the size of the galaxy. The largest known galaxy is a barred spiral galaxy named NGC 6872, and it is five times the size of our Milky Way galaxy. There are a number of galaxies that are larger than our Milky Way, and a number that are smaller. Astrophysicist Hugh Rose says that if a galaxy size is too large, the infusion of gas and stars would disturb the star’s orbit and ignite too many galactic eruptions. And if the size of the galaxy is too small, there would be an insufficient infusion of gas to sustain star formation for long enough time. He also reports that if the galaxy mass distribution if too much in the central bulge, that a life-supportable planet would be exposed to too much radiation. And that if the galaxy mass distribution is too much in the spiral arms, that a life-supportable planet would be destabilized by the gravity and radiation from adjacent spiral arms. J Warner Wallace sums up the information: THE SIZE OF THE MILKY WAY IS FAVORABLE TO LIFE "The Milky Way is also within the proper size ranges to permit life; it is large and spare enough to prevent gravitational disruption from (and collisions with) other star systems, and yet small and dense enough to allow star formation from gas infusion.,,," https://cyberpenance.wordpress.com/2016/10/27/our-universe-4-in-a-galaxy/ Life Requires Galactic and Supergalactic Habitable Zones - DR. HUGH ROSS - APRIL 8TH, 2019 Excerpt: Though research on circumstellar habitable zones has largely focused on the liquid water habitable zone—the distance from the star where water could conceivably exist in a liquid state—another ten circumstellar habitable zones are known to be critical for the survivability of life to date. I have written about these eleven habitable zones here,1 here,2 and here.3 For a planet to be truly habitable it must reside simultaneously in all eleven of these circumstellar habitable zones. Circumstellar habitability, however, is not the only requirement for habitability. For a planet to possibly host life it must also reside in the cosmic temporal habitable zone, the galactic habitable zone, and the supergalactic habitable zone. ,,, Mason and Biermann point out that thanks to a relatively high rate of supernova eruption events, our galaxy maintains a relativistic galactic wind. This wind shields our solar system from deadly extragalactic cosmic rays. However, if the supernova eruption rate in our galaxy were any higher, radiation from the supernovae would prove deadly to advanced life on Earth. Fortunately, the supernova eruption rate in our galaxy is just right. Mason and Biermann also explain how the activity level of our galactic nucleus must be fine-tuned. It takes small dwarf galaxies being regularly absorbed into the nucleus of our galaxy to sustain the ongoing star formation that is critical for maintaining our galaxy’s spiral structure. However, if our galaxy were to absorb or merge with a large dwarf galaxy, that absorption or merger could activate our galaxy’s nucleus. That activation would shower the entire extent of our galaxy with deadly radiation. Fortunately, our galaxy is absorbing dwarf galaxies of the just-right size and at the just-right rate to make possible the survival of advanced life on Earth. https://www.twr360.org/blog/details/2721/life-requires-galactic-and-supergalactic-habitable-zones
bornagain77_{October 11, 2019
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"but spirals pack relatively high amounts of the heavy elements needed to form rocky planets" Um, NO. It's not the SHAPE of a galaxy that matters. It's the AGE. Only 3rd and 4th Generation galaxies (Milky Way is 4th Gen) have the proper combination of heavy and light elements to support Life. 1st & 2nd Generation galaxies lack enough "heavier" elements (including Carbon and Iron) to support Life. 5th Generation and newer galaxies have too many radioactive elements for Life to survive. If Earth's crust contained only a bit more Thorium, the crust would melt. Also remember all the worry about Radon leaking into homes. Oh, also note that VAST sections of galaxies, including Milky Way, are Dead Zones where no Life is possible because dense concentrations of stars produce too much net radiation.vmahuna_{October 10, 2019
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Seversky, A lot of conspiracy theorists claim a lot of things. Why would that matter to you?mike1962_{October 10, 2019
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Some of us would settle for a single fossil bacterium on Mars and forget all the theories.
Would that be enough? Or would conspiracy theorists immediately claim it was planted there as a cunning plan by evil atheist materialists to discredit creationism?Seversky_{October 10, 2019
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