JUN 04, 2019 6:00 AM PDT

Blasts from the Past: Did Dying Stars Turn Our Ancestors into Bipeds?

WRITTEN BY: Daniel Duan

Cassiopeia A (Cas A) a supernova remnant (Pixabay)

A supernova is a brief, final stage event that happens to a massive star. It ends with an epic explosion of its stellar content. When happening close enough to Earth, it could be observed with our naked eyes. However, a recent study suggested that ancient supernovae occurence might have been more than just blips of fireworks to human ancestors--they might have prompted the hominins to walk on their feet.

The rise of bipedalism is considered a crucial part of human evolution. Fossil evidence revealed that between three and four million years ago, our ancestors started to stand on feet, which freed up their hands for other tasks, such as collecting food, making tools, and even starting a fire.

Anthropologists cannot settle on whether we got smart (by growing a bigger brain) before we stood up, or the other way around. But one thing is for sure, the change of locomotion was associated with a change of landscape, meaning the places where the hominins dwelled, mainly northeastern Africa, suddenly had fewer trees but more grass and shrubs.

Scientists have long suspected that frequent lightning and fire might have been the culprits behind the thinning of the forests. The connection between lightning and supernovae, although quite obscure, has previously been proven.

A dying star can be as far as a couple of thousand lightyears away, but its explosion-caused intense gamma radiation can spread across a big region of the galaxy. As the waves of high-energy photons bombard the atoms in Earth's upper atmosphere, they knock the electrons out of their shells and set off electron cascades, which results in intense, frequent lightning. By looking inside the ice-core extracted from the Antarctica, geologists found elevated levels of nitrate ions (nitrogen oxide is a chemical product of lightning), which coincided with the supernovae dated back to 1006 and 1054.

For the recent study by Adrian Melott and Brian Thomas, astronomers from the University of Kansas and Washburn University, the duo built their argument on the previous and current measurement of iron-60, a trace metal can be traced back to the nucleosynthesis process within supernovae, in the seafloor. They discovered that within the deep-sea crust there is an enrichment of  iron-60 all over the world, coinciding with the geological time between the Pliocene Epoch and the Ice Age. Their calculation also confirmed that the ancient celestial explosions could have happened as close as 163 light years away, which made the lighning-caused wildfire more likely.

This latest discovery is published in the Journal of Geology.

Are you interested in learning more about the evolution of human bipedalism? Explore a part of our history in the following video from PBS Eons.

When We First Walked (PBS Eons)

Source: phys.org

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
MAR 06, 2020
Chemistry & Physics
MAR 06, 2020
Father of the Dyson Sphere Passed Away
Last Friday, February 28, 2020, the world said goodbye to Freeman Dyson, was a British American physicist and mathematic ...
MAR 17, 2020
Chemistry & Physics
MAR 17, 2020
Ultra-high-energy Neutrinos to Baffled Particle Physicists: Surprise!
Neutrinos are an aloof member in the sub-atomic particle family: it's electrically neutral, super lightweight (its m ...
MAR 31, 2020
Chemistry & Physics
MAR 31, 2020
Pandemic in Silico: How Maths Modeling Helps Our COVID Fight
The phrase "flattening the curve" is used frequently these days by epidemiologists to describe various measure ...
APR 26, 2020
Cell & Molecular Biology
APR 26, 2020
Researchers Remotely Trigger the Release of Hormones
It may one day be possible to treat hormone-related diseases using this method.
MAY 09, 2020
Chemistry & Physics
MAY 09, 2020
Blood test monitors fat intake
Research published in the Journal of Lipid Research highlights a new blood test that is able to monitor an individual&rs ...
MAY 24, 2020
Chemistry & Physics
MAY 24, 2020
The debate on using oilfield produced water for crop irrigation continues
In an attempt to determine whether it is safe to use oilfield produced water for crop irrigation, a team of researchers ...
Loading Comments...