Cosmic rays and the atmosphere

When the cosmic ray particles enter our atmosphere, they collide and interact with atmospheric gas molecules. As a result of these collisions, high energy pions, muons, and neutrinos are produced as secondary particles.

Pions are high energy particles which decay rapidly to form a high energy muon and two neutrinos. Muons are basically heavy electrons. They share the same properties except that a muon is roughly 200 times as heavy. Because of its mass muons are unstable and will decay into an electron and two neutrinos. These muons decay with a half life of about 1.4 microseconds. Neutrinos are simply particles with little interaction due to their neutral charge.

Muons cause most of the ionization in the lower atmosphere. This ionization occurs when the muon strips an electron away from the gas molecule making it a positive ion. The free electron then latches on to either an already ionized positive ion making it neutral again, or to another gas molecule making it a negative ion. These reactions create an electric field in our atmosphere, thus making lightning possible.

As the human race has evolved, it has changed and adapted to its surrounding environment. Just as humans have adjusted to earths atmosphere and temperature and length of day, we have also adjusted in order to deal with a certain amount of hazardous radiation. The food we eat, the water we drink, the air we breathe, the ground we walk on, the cosmic rays entering our atmosphere; all of these things deliver to us a certain dose of harmful radiation. We have, however, developed physiological processes for dealing with this sub-atomic bombardment. Our bodies have ways of repairing damaged cells, tissues, and even DNA, so that the effects of the radiation can, in a sense, be regarded as negligible.

With the continued depletion of the ozone layer, however, an increased number of cosmic rays is entering our atmosphere and falling to the earth. If the rate of increase of cosmic rays entering our atmosphere begins to surpass our ability to deal with radiation exposure, then our race could be in great danger.