JAKARTA, NNC - The nearest star that exploded 8 million years ago could provoke the evolution of our ancestors, a new study suggests.
Supernovas may have caused more lightning storms on Earth, which in turn triggered forest fires across Africa. This fire could explain the revival of East African Savannah around that time, which experts say is the key to the early evolution of hominins. How Savannah in Africa eight million years ago has long been a mystery to scientists.
While savanna is now dominated by a plant called C4 grass, it emerged 20 million years ago, long before they became the dominant species on the plains. Some experts suggest grass turnover eight million years ago came thanks to a spate of forest fires. Grasses usually grow back quickly after forest fires, while trees take longer to recover, which means ordinary fire will expand savanna in Africa.
Now a team of US researchers led by experts at Washburn University in Kansas suggests supernovas trigger widespread fires in the savanna, as quoted by Daily Mail.
The deep-sea sediments contain high levels of the iron-60 isotope, which is produced in larger stars. The presence of the -50 iron shows at least one supernova nearby eight million years ago.
The researchers created a computer model detailing what would happen if a supernova exploded around Earth at that time. This gives the impression that the explosion sends a high-energy cosmic ray all over the planet.
Scientists previously linked this process with lightning formations.
The US team then used the vegetation model to calculate how the increase in the number of lightning storms in Africa and change the life of the plants.