Chapter 14, Problem 1CO

Interpretation Introduction

Interpretation: Cosmic rays and some of the ways by which they influence earth and its atmosphere should be described.

Concept introduction:

Cosmic rays are very high energy rays. It is generally originated outside the solar system. Sometime these rays interact with the earth atmosphere and result in showers of secondary particles. These secondary particles can reach the surface of the earth.

The composition of cosmic rays is high energy protons and atomic nuclei. The source of these cosmic rays is either sun or outside of the solar system.

Answer to Problem 1CO

Cosmic rays can produce many unstable isotopes in earth they can cause change in climate and can also affects the electronic circuits.

Explanation of Solution

Cosmic rays are divided into mainly three types: galactic cosmic rays, extragalactic cosmic rays and solar energetic particles. Primarily, cosmic rays are composed of protons and alpha particles (99%) along with the small number of heavy nuclei approximately 1%. It also consists of minute number of positrons and antiprotons. The primary cosmic ray decay to form the secondary cosmic rays.

Here, primary cosmic rays are originated from the outside of the solar system. On interaction with the atmosphere of the earth, they are converted into secondary particles.

Effects of the cosmic rays on the atmosphere of the earth:

Cosmic rays change the chemistry of the atmosphere. They can ionize the molecules of nitrogen and oxygen present in the atmosphere leading to number of chemical reactions. They are responsible for formation of number of unstable isotopes in the atmosphere of the earth.

For example, the production of C-14 takes place as follows:

$n{+}^{14}\text{N}\to p{+}^{14}\text{C}$

Due to these rays the level of C-14 remains constant in the atmosphere which is approximately 70 tons from the past 100,000 years.

They participate as a major fraction in the total amount of radiation exposure by human beings on the earth in a year. The exposure increases with increase in the altitude. Thus, in the higher-altitude cities the exposure of cosmic rays raised to 1/4th of total exposure of radiation. Thus, the airlines flying in such higher altitudes can be exposed to the radiation.

Effect on the electronics: The components of circuit in the electronic integrated circuits can be altered by the cosmic rays due to its high energy. This results in the occurrence of the transient errors for example corrupted data or wrong performance of the CPUs. These errors are called soft errors. This is problem with electronics in higher altitudes like satellites. Now, due to decrease in the size of transistors, the concern is also raising in the ground-level electronics.

Effect on the aerospace travel:

Cosmic rays is an important barrier in the way of interplanetary travel by spacecraft. Some strategies are used to minimizing the damage to the electronics and human beings due to the cosmic rays, this includes, physical or magnetic shielding for the spacecrafts.

Effect on the climate:

Cosmic rays are responsible for the major changes in the climate. The cosmic rays along with the gamma rays deriving from the local supernovae can affect cancer and mutation rates. They can affect the rate of formation of clouds and cause global warming.

Conclusion

Thus, the cosmic rays can affect the earth and its atmosphere in different ways.