Can supernovae hinder the formation of life in galaxies? (Beginner)

Is it possible that the frequency of supernovas in galaxies have a sterilizing effect and making much of them inhabitable for life and long term evolution?

Yes, supernovae can definitely have an influence on the presence of life in galaxies. They can destroy life not only on planets around the stars going through the explosion, but also on planets of neighbouring stars.

We define the region around a star where there can be life as the "habitable zone" (it corresponds the the range of distances from the star such that there can be liquid water, which we believe is necessary for the formation of life). When a star is nearing the end of its life (before the supernova explosion happens), its temperature and size increases. This can make life impossible in regions that previously were within the habitable zone. For example, when the Sun will become a giant star at the end of its life (in about 5 billion years) it will become so large, the the Earth might be engulfed in it! In any case, temperatures will be so high that all the water will evaporate, making it impossible for Earth to sustain life.

So there are direct consequences for planets around the star undergoing the supernova explosion. Another aspect of the supernova explosion is that huge amounts of high energy gamma-rays and x-rays are emitted. This can have negative influence on the presence of life on planets around other nearby stars.

I described above what the habitable zone of a planet is. There is also something we call the "galactic habitable zone", which is the region of our galaxy where we would expect to find life. The galactic habitable zone is probably a ring around the centre of the Galaxy, away from the central part but not too close to the edge. That is because in the outer parts of the galaxy there aren't enough metals available, which astronomers believe are necessary to form planets, and because in the inner part there are too many hot stars producing x-rays and gamma-rays.

So in that sense, supernovae can definitely influence the presence of life around them, and make some regions of galaxies very hostile to the formation of life.

This page was last updated June 27, 2015.

About the Author

Amelie Saintonge

Amelie is working on ways to detect the signals of galaxies from radio maps.

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