GK
BIG BANG THEORY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
It means the star is staying the same distance from Earth.
|
|
|
It means the star is moving away
|
|
|
It means the star is getting closer to Earth.
|
|
|
None of the above
|
Detailed explanation-1: -Ever since 1929, when Edwin Hubble discovered that the Universe is expanding, we have known that most other galaxies are moving away from us. Light from these galaxies is shifted to longer (and this means redder) wavelengths-in other words, it is ‘red-shifted’.
Detailed explanation-2: -Redshift is an example of the Doppler Effect. As an object moves away from us, the sound or light waves emitted by the object are stretched out, which makes them have a lower pitch and moves them towards the red end of the electromagnetic spectrum, where light has a longer wavelength.
Detailed explanation-3: -A star appears to be redshifted when it is moving away from the earth. In this case, the wavelengths of the emitted light by the star seems to have shifted towards the red end of the electromagnetic spectrum.
Detailed explanation-4: -The fabric of space expands. This is the cause primarily responsible for the redshifting we see of distant galaxies. Light travels through the fabric of space, which is expanding as time progresses since the Big Bang, and that expanding space stretches the wavelength of the light that travels through it.