
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
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,
A lot of conspiracy theorists claim a lot of things. Why would that matter to you?
“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.
as to this claim,
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: