Supernova Cosmic Rays Accelerated Earth’s Evolution
Over two million years ago, something intriguing occurred with the viruses that infect fish in Lake Tanganyika, located in East Africa. Scientists have observed that these viruses diversified rapidly during this period, and the cause of this increased mutation rate remains a mystery to researchers.
Lake Tanganyika is notable for being the deepest lake in Africa, stretching over 400 miles (around 645 kilometers) and containing a significant amount of the world’s freshwater. It is situated in the East African Rift, surrounded by tall highlands, which isolate it from its neighboring areas.
Researchers think there might be a connection between the increased variety of these fish-infecting viruses and higher levels of cosmic radiation, which were present during the same time frame. Cosmic rays are highly energetic particles that travel through space almost at the speed of light, originating from various sources like supernovae, the Sun, and objects beyond our own galaxy.
When these cosmic rays hit Earth’s atmosphere, they create a cascade of secondary particles that can arrive at the surface. Some cosmic rays are so powerful they can even interfere with electronic devices, disrupt satellite communications, and slightly raise radiation levels for astronauts and those on high-altitude flights. Scientists are still learning about these cosmic phenomena, but it’s clear that they play a significant role in the universe’s high-energy processes.
Despite their name seeming outlandish, cosmic rays are a natural part of life on Earth. The planet’s magnetic field and atmosphere act as protective barriers, blocking most of these rays before they can reach us. However, they still influence our environment; some studies suggest they might even affect cloud formation and, consequently, climate change.
Previous studies have shown evidence of radioactive iron found in deep-sea sediments, indicating the repercussions of a nearby supernova explosion that happened around 2.5 million years ago. This explosive event released intense cosmic radiation, which may have impacted the Earth’s surface for approximately 100,000 years.
Joins researchers Caitlyn Nojiri, who is the lead author of these studies, stated, “It’s fascinating to discover how events in distant space can influence our lives or the planet’s habitability.” This groundbreaking research led to an exploration of whether cosmic radiation has influenced the changes in viruses found in fish in Lake Tanganyika.
While Nojiri and her colleagues are careful not to claim definitive links between cosmic events and the emergence of new aquatic viruses, they noted that both seemed to have occurred within the same timeframe. One of their most exciting findings was the overlap in time between a faraway stellar explosion and a local surge of viruses.
By tracking data on iron-60, a radioactive isotope produced by supernova explosions, scientists were able to locate the area from which these cosmic rays originated. They believe that our solar system passed through a region known as the Local Bubble, filled with low-density gas shaped by multiple supernovae. This passage could explain the increased cosmic rays reaching Earth, which, at certain intensities, may lead to genetic mutations and alter biological processes.
The distinct nature of Lake Tanganyika, with its isolated fish species, further adds to the allure of studying how cosmic rays influence viral mutations. Researchers believe that damage to DNA strands during replication could encourage greater viral diversity, prompting further study into evolutionary events and their potential links to cosmic radiation.
Though the supernova event occurred millions of years ago, scientists are still keen to investigate its lingering effects. They ponder whether modern species carry the remnants of ancient mutations triggered by cosmic energy and if current levels of cosmic radiation might hint at future occurrences that could similarly impact life on Earth. Studying the connections between cosmic events and evolution can help us understand life’s changes throughout geological time.
Nojiri hopes to continue her research in astrophysics, motivated by her fascination with the ways cosmic events might influence life on our planet. Her ongoing work emphasizes the enduring impact of cosmic forces on ecosystems and strengthens the notion that they can shape life in unexpected but significant ways.
