A remarkable link between the number of nearby exploding stars, called supernovae and life on Earths has been discovered.
Evidence demonstrates a close connection between the fraction of organic matter buried in sediments and changes in supernovae occurrence. This correlation is apparent during the last 3.5 billion years and in closer detail over the previous 500 million years.
The correlation indicates that supernovae have set essential conditions under which life on Earth had to exist. This is concluded in a new research article published in the scientific journal Geophysical Research Letters by senior researcher Dr. Henrik Svensmark, DTU Space.
According to the article, an explanation for the observed link between supernovae and life is that supernovae influence Earth’s climate. A high number of supernovae leads to a cold climate with a significant temperature difference between the equator and polar regions. This results in strong winds and ocean mixing, vital for delivering nutrients to biological systems. High nutrient concentration leads to a larger bioproductivity and a more extensive burial of organic matter in sediments. A warm climate has weaker winds and less mixing of the oceans, diminished supply of nutrients, a smaller bioproductivity, and less burial of organic matter.
“A fascinating consequence is that moving organic matter to sediments is indirectly the source of oxygen. Photosynthesis produces oxygen and sugar from light, water and CO2. However, if organic material is not moved into sediments, oxygen and organic matter become CO2 and water. The burial of organic material prevents this reverse reaction. Therefore, supernovae indirectly control oxygen production, and oxygen is the foundation of all complex life,” says author Henrik Svensmark.
In the paper, a measure of the concentration of nutrients in the ocean over the last 500 Million years correlates reasonably with the variations in supernovae frequency. The concentration of nutrients in the oceans is found by measuring trace elements in pyrite (FeS2, also called fool’s gold) embedded in black shale, which is sedimented on the seabed. Estimating the fraction of organic material in sediments is possible by measuring carbon-13 relative to carbon-12. Since life prefers the lighter carbon-12 DOI: 10.1029/2021GL096376