* Gamma rays are very energetic: They have much higher energy than visible light or even X-rays. This means they interact strongly with matter.
* Atmospheric absorption: When gamma rays enter the atmosphere, they collide with atoms and molecules. These collisions cause the gamma rays to lose energy, and eventually, they are absorbed completely.
However, some gamma rays do make it through:
* Lower energy gamma rays: Gamma rays with lower energies are less likely to interact with the atmosphere and can penetrate to the surface.
* Cosmic rays: Some high-energy cosmic rays, which are primarily protons, can interact with the Earth's atmosphere and produce secondary gamma rays.
* Natural sources: Certain natural sources on Earth, like radioactive isotopes, can also emit low-energy gamma rays.
Examples:
* Medical imaging: Medical equipment like PET scans use gamma rays, which can penetrate through the body and provide detailed images.
* Cosmic ray showers: When high-energy cosmic rays hit the atmosphere, they create showers of secondary particles, including gamma rays, which can reach the ground.
In summary:
While the Earth's atmosphere blocks most gamma rays, some low-energy gamma rays and secondary gamma rays from cosmic rays do reach the surface. These rays have various applications and play a role in natural processes.
