GENERAL KNOWLEDGE

GK

BIG BANG THEORY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
When viewed from Earth, the light from a very distant galaxy shows a blue shift. This is evidence that this distant galaxy is
A
moving away from Earth
B
revolving around the Milky Way
C
moving toward Earth
D
revolving around the Sun
Explanation: 

Detailed explanation-1: -For a Blueshift the observed wavelength o of electromagnetic radiation is shorter than that emitted by the source. The source moves towards the observer. So if the light coming from a galaxy is showing blueshift on the earth’s surface, then the galaxy is approaching the earth.

Detailed explanation-2: -"Blueshift” is a term that astronomers use to describe an object that is moving toward another object or toward us. Someone will say, “That galaxy is blueshifted with respect to the Milky Way", for example. It means that the galaxy is moving toward our point in space.

Detailed explanation-3: -If a star is traveling towards us, its light will appear blueshifted, and if it is traveling away the light will be redshifted. This shift in color will not change the apparent color of the star enough to be seen with the naked eye.

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