Supernovae 'caused at least two mass extinctions on Earth'

(CLO) Two of the five greatest extinction events in Earth's history may have originated from the devastating impact of supernova explosions near our planet, according to a new study from Keele University.

Scientists believe these explosions may have destroyed the ozone layer, causing acid rain and exposing the Earth's surface to dangerous levels of ultraviolet radiation from the sun.

Research suggests that supernova explosions may have caused the extinction events at the end of the Devonian (about 372 million years ago) and the Ordovician (about 445 million years ago) periods.

The Ordovician extinction event killed 60% of marine life when life was still largely concentrated in the water. Meanwhile, the Late Devonian saw the extinction of 70% of species on Earth, including a major shift in the ancient fish populations that once dominated the oceans.

Supernova 1987a (center) in a galaxy neighboring our own Milky Way. Image: NASA, ESA

Scientists have previously suspected that these two disasters were linked to ozone depletion, but there was no concrete evidence. The new study, published in the Monthly Notices of the Royal Astronomical Society, analyzed the rate at which supernovae occur in the galaxy and found that it coincided with the timing of the extinction events.

Scientists say supernovae are not only giant explosions that release enormous amounts of energy, but they also play a vital role in life. They create and disperse heavy chemical elements necessary for the formation of stars, planets, and life. However, if a planet gets too close to a supernova, the consequences can be dire.

To test this hypothesis, the team looked at massive stars within a kiloparsec (about 3,260 light years) of the Sun and tracked the rate at which supernovae occurred. They then compared this to the rate of mass extinction events on Earth and found a remarkable match.

Dr Nick Wright, one of the study's authors, stressed: "Supernovae are some of the most powerful explosions in the universe. If a massive star exploded close to Earth, the consequences would be catastrophic for life. This research shows that this may have happened in the past."

Despite the risk, astronomers currently believe that there is no serious threat from supernovae in the near future. The two nearest stars to Earth that have the potential to go supernova are Antares and Betelgeuse, but they are both more than 500 light years away. Previous simulations have suggested that a supernova explosion at this distance would have no significant impact on Earth.

Hoai Phuong (according to Phys, Science Alert)

Source: https://www.congluan.vn/nghien-cuu-sieu-tan-tinh-tung-giay-ra-it-nhat-hai-cuoc-tuyet-chung-tren-trai-dat-post338492.html