Earth's ancient climate was influenced by unexplained ‘mystery particles' from outer space. Explosive stellar events may be forecasted by analysing iron isotopes in interstellar dust. New research indicates that nearby supernovas, the giant death explosions of stars, may have upset the planet's atmospheric balance thousands of years ago. These bursts, creating torrents of high-energy radiation, may have triggered global cooling, wildfires, and mass extinctions, researchers have mentioned. By tracking down those cosmic footprints of the past, scientists say, they may even be able to learn more about the environmental hazards posed by future supernovas and be readier to deal with them.

As per a report by Space.com, supernovas occur when stars more massive than our sun collapse in on themselves under the force of their own gravity, leaving behind either black holes or neutron stars and ejecting extremely powerful radiation. If such a blast occurred within 30 light-years, researchers warn, it could strip away Earth's atmosphere entirely. But even explosions hundreds of light-years away, such as from Betelgeuse, 700 light-years away, could alter climate patterns and increase ultraviolet exposure on Earth.

Robert Brakenridge, a senior researcher at the Institute of Arctic and Alpine Research, studied 15,000 years of tree ring data and identified 11 spikes in radioactive carbon. These anomalies, he suggests, may be evidence of Earth being struck by cosmic radiation from past supernovas. “We have abrupt environmental changes in Earth's history,” Brakenridge pointed out. “We see these changes. So, what caused them?”

His model suggests that high-energy photons from supernovas could irradiate and destroy the ozone layer, allowing more ultraviolet radiation to reach Earth's surface, and erode the stratosphere, which stores a decent amount of methane, both crucial contributors to Earth's greenhouse gas regulation. The plunge in methane would have cooled the planet, possibly setting in motion climatic changes and die-offs of many species.

Although solar flares are another potential candidate for the carbon spikes, Brakenridge explains that more geological evidence, such as ocean sediment and ice cores, could tie the supernovae to these events. Insight into this relationship could assist scientists in predicting atmospheric consequences. If/when Betelgeuse or another nearby star goes supernova.