GENERAL KNOWLEDGE

GK

BIG BANG THEORY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If a star’s spectral lines are blue shifted it means
A
That the star is getting closer to Earth
B
Moving parallel to the Earth
C
That the star is getting farther away from Earth
D
That the star is going to explode
Explanation: 

Detailed explanation-1: -For example, if a star is moving toward us, its lines will be observed at shorter wavelengths, which is called “blueshifted". If the star is moving away from us, the lines will appear at longer wavelengths, which is called “redshifted". This is called “Doppler shift."

Detailed explanation-2: -If a star approaches or recedes from us, the wavelengths of light in its continuous spectrum appear shortened or lengthened, respectively, as do those of the dark lines.

Detailed explanation-3: -Doppler shift So, if a star is moving towards Earth, it appears to emit light that is shorter in wavelength compared to a source of light that isn’t moving. Because shorter wavelengths correspond to a shift towards the blue end of the spectrum, this is called blueshift.

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