Will the Earth survive a nearby supernova explosion?

Do explosions of relatively nearby supernovae, by cosmic standards, threaten earthly life? Will the Earth survive such an explosion? Scientists from the Cyprus Institute decided to look into this. Their research was published in the scientific journal Communications Earth & Environment (CEE).

Supernovae and their danger

Supernovae explode within 100 parsecs (326 light years) of our planet about once every million years. Such explosions are accompanied by colossal bursts of energy, which can cause damage even at a great distance from the epicenter.

It is believed that gamma-ray bursts and cosmic rays produced during the explosion can deplete the Earth's ozone layer, allowing ionizing ultraviolet radiation to reach the planet's surface. These effects could lead to an increase in the amount of aerosol particles in the atmosphere, increased cloudiness and global cooling.

In a new study, scientists looked at the possible causes of the end-Devonian extinction event about 370 million years ago by finding plant spores burned by ultraviolet radiation. This suggests that something depleted the Earth's ozone layer at that time, and a supernova explosion may have been one of the reasons.

Today's risks

The researchers carried out calculations and came to the conclusion that the modern ozone layer of the Earth has become more stable and is capable of protecting the biosphere from supernovae within 100 parsecs. Simulations showed that the explosion of a star 326 light-years away would cause ionization 100 times greater than current levels. In this case, the average loss of stratospheric ozone would be about 10% on a global scale - about the same as that caused by anthropogenic pollution. Global cooling will also increase, but not to a dangerous degree.

The authors of the study emphasized that in such a scenario, the global biosphere of our planet will be able to survive without significant losses. However, at the local level, people, animals and plants may experience dangerous effects due to a hundredfold increase in cosmic radiation.

Thus, the study showed that although supernova explosions pose a serious threat, the Earth's ozone layer is currently able to protect the biosphere from significant losses. However, local impacts may be significant and require further study.