Book Assignment on Astronomy

The Red and blue shift concept are fundamental and integral to charting in the process of universe expansion. The shifts bring out a clear description of how changes in light are affected by the movement of objects such as stars and galaxies across space farther away or closer to the earth, the movement portrayed by the general elements existing in the space. This is known as the Doppler's shift. It asserts that galaxies themselves move through static space-time.

When galaxies show an equal number of redshifts and blueshifts mixed uniformly in all directions, this will imply that the universe is a static, with no random movement taking place and in this case what is happening is that the observed shifts are as a result of the random galaxy motions that is taking place within the universe.

In the process that all the galaxies are showing blueshifts with a size that increase in proportion to the distance covered, However, this would indicate a serious collapse of the universe. In some instances, the galaxies on one half of the sky might show redshifts while the other half show blueshifts, showing an opposite movement in the whole process of operation. Basically, the interpretation of this is that the earth's galaxy is perceived to be moving through a static universe at a higher speed than that of the random motions of other galaxies. When this happens, all the galaxies in the direction of the earth galaxy will appear blueshifted, and those in the opposite direction would appear redshifted. This generally shows a clear differentiation on the whole moving process. Similarly, it is also identified that this configuration could also take place when the earth's galaxy is static with no single movement, and the rest of the whole world is flowing past it (Seeds and Backman).

Calculate the distance of the galaxy that has a z of 0.02.

Technically, the distance of galaxies can be calculated using the Hubble's law; this is one of the scientifically recognized standards when it comes to calculation of the existing distance. On the other hand, the Hubble's law demonstrates that the velocity of an object is directly proportional to its distance covered by the object when the whole object is subjected to motion. This means that the farther away an object is, the faster it is likely to be moving away from an observer and hence ones action leads to initiation of various movements.

Given, the redshift of a given galaxy as z=0.02, we can use the Hubble's constant to calculate its distance through a formula; velocity (km/s) = H x distance (Mpc). This is recognized as one of the recognized standards that yield the whole formula, and hence the result can be achieved accordingly.

Taking, into consideration and understanding that the speed of light is e, 3 x 105 km/s, we are in a position of calculating the velocity of the galaxy. In that, for velocity to be realized, then the speed of light can be achieved by calculating the redshift and multiplying with the speed of light.

Velocity = speed of light x redshift

= 3 x 105 km/s x 0.02

= 6000 km/s

Hubble's constant is given by; 65 km/s/Mpc.

Therefore, distance = velocity/H

= (6000km/s)/65km/s/Mpc

With the final results being considered as

= 92.31Mpc

Where; Mpc means Mega-parsec a measure of distance commonly used by astronomers, and it equals 3.2 light-years.

Work Cited

Seeds, Michael A., and Dana Backman. Horizons: Exploring the Universe. Cengage Learning, 2016.