Cosmic radiation consists of high-energy particles that travel at nearly the speed of light, originating from explosive cosmic events like supernovae and solar flares. These particles constantly bombard Earth and can penetrate the atmosphere and bodies, posing certain health risks especially at high altitudes or in space.
At ground level, Earth’s atmosphere and magnetic field provide effective shielding, allowing only a small fraction of cosmic radiation to reach people. Average radiation exposure for an individual at sea level is about three millisieverts (mSv) per year, which is generally safe. However, exposure increases with altitude, such as for residents of mountainous cities or airline passengers and crew, who receive significantly more radiation during flights comparable to a chest X-ray per cross-country trip.
Prolonged or high-dose exposure to cosmic rays can damage DNA, increase cancer risk, cause cataracts, and affect brain cell generation. Astronauts aboard the International Space Station and on potential Mars missions experience much higher doses due to thin or absent atmospheric shielding, raising significant health concerns.
Researchers are exploring methods to protect space travelers including special shielding materials and scheduling activities during low solar activity periods. Advances in medical treatments are also being investigated to mitigate radiation damage.
For most people on Earth, cosmic radiation poses minimal health risks due to natural protection. Current knowledge continues to improve as space exploration advances, highlighting the importance of understanding cosmic radiation’s effects on human health.