Star Explosions, Or Supernovae, Have Helped Sustain Life On Earth For 3.5 Billion Years: Study

Star explosions, or supernovae, have created the essential conditions to sustain life on Earth, according to a new study. Exploding stars influence Earth's climate.

Star explosions, or supernovae, have created the essential conditions to sustain life on Earth, according to a new study. (Photo: Twitter/@NASA)

New Delhi: The number of neighbouring exploding stars, called supernovae, and life on Earth are strongly associated, a new study has found. 

There is a correlation between the fraction of organic matter buried in sediments and the changes in supernovae occurrence, as suggested by evidence. 

During the last 3.5 billion years, the link has been apparent, and it has become clearer over the past 500 million years.

The study, conducted by the Technical University of Denmark, was recently published in the journal, Geophysical Research Letters.

Star Explosions Have Created Essential Conditions For Sustaining Life On Earth

Star explosions, or supernovae, have created the essential conditions to sustain life on Earth, according to the study. 

Supernovae influence Earth’s climate, which explains the observed correlation between exploding stars and life. A high number of supernovae result in a cold climate with a significant temperature difference between the equator and polar regions. As a result, strong winds and ocean mixing occur, which are important for delivering nutrients to biological systems.

A larger bioproductivity and a more extensive burial of organic matter resulted from high nutrient concentration.

On the other hand, a warm climate results in weaker winds and less mixing of the oceans, reduced supply of nutrients, lower bioproductivity, and less deposition of organic matter.

In a statement issued by the Technical University of Denmark, study author Henrik Svensmark said that a fascinating consequence is that moving organic matter to sediments is indirectly the source of oxygen. Oxygen and sugar are produced from light, water, and carbon-dioxide through photosynthesis. 

Svensmark explained that oxygen and organic matter become carbon dioxide and water if organic matter is not moved to sediments. Hence, supernovae indirectly control oxygen production, and oxygen is the foundation of life, he added. 

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 study said. Measuring trace elements in pyrite (FeS2, also known as fool’s gold) embedded in black shale can help determine the concentration of nutrients in the ocean.

Pyrite is sedimented on the seabed. Also, it is possible to estimate the fraction of organic matter in sediments by measuring carbon-13 relative to carbon-12. 

Life prefers the lighter isotope of carbon, which is carbon-12. Therefore, the amount of biomass in the world’s oceans changes the ratio between carbon-12 and carbon-13 measured in marine sediments.

Svensmark said that the new evidence points to an extraordinary interconnection between life on Earth and supernovae, mediated by the effect of cosmic rays on clouds and climate. 

Supernovae Are Linked To Climate

The fact that ions from cosmic phenomena help the formation and growth of aerosols, and influence cloud fraction, was demonstrated by Svensmark and his colleagues in previous research. The link between cosmic rays and clouds is important because clouds can regulate the solar energy which reaches Earth’s surface, the study said.

Also, Earth’s climate changes when the intensity of cosmic rays changes, according to empirical evidence. 

When heavy stars explode, they produce cosmic rays made of elementary particles with enormous energies, Svensmark explained. He added that cosmic rays travel to the solar system, and some end their energy by colliding with Earth’s atmosphere.
On Earth, cosmic rays are responsible for ionising the atmosphere. This is how exploding stars influence Earth’s climate.