Millions of years ago, a massive star exploded in space, sending radiation toward Earth.
A new study suggests this cosmic event may have caused big changes in the viruses that infect fish in Africa’s Lake Tanganyika.
Researchers from the University of California, Santa Cruz, believe that this explosion may have played a role in the evolution of these viruses by exposing them to high levels of cosmic radiation.
Lake Tanganyika is the deepest lake in Africa and holds a huge amount of freshwater.
Between two and three million years ago, scientists noticed an explosion of new virus species in this lake. They now think this may have been triggered by the radiation from a distant supernova.
A team led by Caitlyn Nojiri, a recent undergraduate student at UC Santa Cruz, studied traces of a radioactive element called iron-60, which is produced by supernovae.
By analyzing the breakdown of this element, they were able to date it back to a supernova that occurred about 2.5 million years ago.
“It’s amazing to think that something so far away in space could have an impact on life on Earth,” said Nojiri.
The researchers believe that when this supernova exploded, it sent cosmic rays toward Earth for about 100,000 years. These rays could have broken DNA strands, leading to mutations in living organisms.
Other studies have shown that radiation can damage DNA, which can speed up evolutionary changes.
The team found that their findings matched a recorded spike in radiation on Earth from that time, something that had puzzled astronomers before.
Nojiri and her colleagues also came across a study about viruses in Lake Tanganyika, showing that there was an explosion of virus species around the same period. While they can’t confirm that the supernova directly caused this, the timing is an interesting coincidence.
“We’re not saying it’s a direct link, but the timing is curious,” Nojiri explained. “It’s possible that the radiation from the supernova helped drive these evolutionary changes.”
Nojiri’s journey into astronomy was unexpected. She spent time at community college without knowing what she wanted to study. When she transferred to UC Santa Cruz, Professor Enrico Ramirez-Ruiz encouraged her to apply for a program called UC LEADS, which supports students from underrepresented groups in science.
“Enrico literally walked me to the STEM diversity office and encouraged me to get involved,” she said.
She later joined Lamat, a program that helps students from nontraditional backgrounds get hands-on experience in astronomy research.
“Science benefits from having people with different perspectives,” Ramirez-Ruiz said. “This study is an example of how bringing diverse voices into physics can lead to new ideas and discoveries.”
The study provides new evidence that cosmic events, like supernovae, can shape life on Earth in unexpected ways. The researchers plan to continue exploring these connections between space and life on our planet.
“The next time you look at the night sky, think about how those distant stars could be influencing life on Earth, even after they’re gone,” Nojiri said.
Source: UC Santa Cruz.
