When a massive star explodes in a brilliant flash called a supernova, it sends out a wave of high-energy particles into space.
These particles can travel for thousands of light-years, crossing solar systems—and potentially reaching Earth.
A new study suggests that these cosmic explosions might have triggered sudden climate changes on our planet in the past, and could possibly do so again.
In a paper published in the Monthly Notices of the Royal Astronomical Society, Robert Brakenridge, a senior research associate at the Institute of Arctic and Alpine Research (INSTAAR), lays out new evidence connecting supernovae with abrupt shifts in Earth’s climate.
Scientists already know that our planet has gone through many sudden environmental changes. The big mystery has always been: what caused them?
Brakenridge believes the answer might lie in the stars. Specifically, nearby supernovae could be powerful enough to affect Earth’s atmosphere in dramatic ways.
His research models how radiation from these explosions could thin the ozone layer and reduce greenhouse gases like methane.
That combination would allow more harmful ultraviolet light from the sun to reach the surface, while also reducing the planet’s ability to trap heat. The result? A cooler Earth, more wildfires, and possible extinctions.
This isn’t Brakenridge’s first time exploring the idea. He and others have been studying the possible link between supernovae and climate for decades.
But in the past, the idea was mostly theoretical—based on physics and space models, not direct Earth evidence.
Now, thanks to improved space telescopes and a more detailed understanding of how supernova radiation behaves, Brakenridge has been able to build a more precise model.
Since we’re not currently being hit by supernova radiation, Brakenridge turned to history for clues. One place he looked was in tree rings. As trees grow, they trap carbon from the atmosphere in their trunks.
If a supernova affects the Earth’s atmosphere, it could change the type of carbon that trees absorb. By studying these rings, scientists can get a snapshot of what the atmosphere was like at different points in time.
In his analysis of 15,000 years of tree ring data, Brakenridge found 11 sudden spikes in radioactive carbon. He believes these could match 11 supernovae that astronomers know occurred at about the same time.
The timing and intensity of these events line up well, suggesting a possible link between the cosmic blasts and climate shifts here on Earth.
To be clear, supernovae aren’t the only possible cause. Solar flares from the sun could also create similar patterns. But Brakenridge argues that the case for supernovae is getting stronger, and further studies—such as ice cores or ocean sediments—might provide even more evidence.
Understanding this connection isn’t just about solving mysteries of the past. It could help us prepare for the future.
A nearby star, Betelgeuse, is expected to explode as a supernova sometime in the next 100,000 years—maybe even tomorrow. If such an event sends radiation toward Earth, it could have serious effects on our climate and environment.
Brakenridge believes that with better models and more data, scientists could one day predict how these distant cosmic events might impact life on Earth. As our ability to observe space improves, so too does our ability to understand how deeply connected we are to the stars.
Source: University of Colorado at Boulder.
