Cosmic rays could harm brains of astronauts, particularly on long journeys such as a trip to Mars, according to a new finding. A journey to the Red Planet could take up to two-and-a-half years to complete, and NASA has stated a goal of putting humans on Mars sometime in the 2030s.
Galactic cosmic rays (GCR's) are created outside our solar system, but usually within the Milky Way galaxy. They consist of the protons and neutrons of atomic nuclei without the electron shells usually found around atoms. Those particles, created in supernova explosions, are torn off the nuclei as the cosmic rays course through the vast distances between the galaxies. These tiny groups of particles are accelerated around the galaxies, driven by the magnetic field around our galaxy.
Cosmic rays like those that will be absorbed by space travelers headed to the Red Planet could result in declines in cognitive behavior similar to those seen in dementia patients, a new study suggests.
Mice were exposed to high-energy particles similar to cosmic rays as part of a NASA-funded experiment. The rodents were genetically modified to possess fluorescent green neurons ito aid in the study. Six weeks after the mice were exposed to the radiation, they were examined by researchers.
Changes were witnessed in the structure and constitution of nerve cells within the brains of the animals. The tiny mammals displayed significant declines in cognition after long-term exposure to the positively charged rays. After being exposed to the radiation, the rodents acted sluggish and had poor memory along with declines in learning ability and curiosity.
The magnetosphere of the Earth protects life on this planet, or just above it, from the effects of the powerful radiation. However, in deep space, there is little protection from the rays. Without shelter from the radiation, astronauts would likely suffer many of the same effects as the mice in the experiment. This could result in reductions of mental capacity that could hinder a mission, particularly in the case of unexpected events, when quick thinking could mean life or death to those aboard the spacecraft.
"Previous studies show synaptic impairment or loss of synapses is an early and invariant feature of Alzheimer's disease, and there is a strong correlation between the extent of synapse loss and the severity of dementia," said Vipan Kumar Parihar, a neuroscientist with the University of California, Irvine.
Shielding to protect space travelers from cosmic rays would need to be integrated into any spaceship designed to ferry humans to Mars, but no system would completely prevent exposure.
Analysis of how mice are affected by radiation similar to cosmic rays and what this could mean for future space travelers heading to Mars was profiled in the journal Science Advances.
Photo: Robert Scoble | Flickr
