Chapter 16.2, Problem 28SSC

To determine

ToExplain:The way astronomers can determine that our galaxy, the Milky Way is moving towards Andromeda, a neighbouring galaxy.

Explanation of Solution

Introduction:

An astronomer can use the phenomena called Dopler Shift to study about the movement of astronomical objects relative to Earth. In Dopler Shift they use the light spectrum which shows the two shifts: blue shift and red shift.

When the source of the light coming towards the observer, then the wavelength of emission light reduces and it shifts towards blue end, so it is known as blue shift.

If the object moves away from an observer, then the wavelength of emission light will increase and shift towards red end, and known as red shift.

Conclusion:

As our galaxy Milky Way and the Andromeda, the neighbouring galaxy are moving towards each other, hence the astronomers will observe the blue shift.