The observation has been made recently that Life in the inner galaxy would be bombarded by comets
WE’RE lucky Earth resides in the Milky Way’s suburbs. Intense comet bombardment near the galaxy’s centre may make it tough for life to gain a foothold there.
Earth and the other planets of our solar system suffer occasional impacts when comets are disturbed from their orbits around the sun by the gravity of nearby stars and gas clouds.
The effect is stronger closer to the galaxy’s centre, where stars and gas clouds are more tightly packed. More than twice as many comets are shaken loose to potentially hit planets at half our distance to the centre, according to simulations by Marco Masi of the University of Padua, Italy, and his colleagues
People who study such things are telling us that the Earth is at the just-right distance from the galactic center, at the just-right distance from the Sun, with a just-right moon that creates tides, more critical for life than was once understood. The moon also helps keep the Earth at its just-right axial tilt so that we have seasons, which are sometimes annoying, but also critical for advanced life.
These facts are just the tip of the iceberg about the exceedingly rare “just-rightness” of our world for advanced life, and also the “just-rightness” of our world for intelligent life (that would be us) to be able to learn about the universe by observation.
Some people think this is a huge accident.
You can read more about this in these two books: