Hi folks....am back to blogging after a while now...thought of comin back with a bang...dunno how much of a bang this will be:)
So...the first thing you'll have to know in order to understand this concept wud be Doppler effect and its extension into light waves...
For those who are new to Doppler effect...
Whenever there is a relative motion between the source of sound and the observer, there is a change in the frequency of sound observed by the observer...
If the relative motion is such that the source and observer approach each other, there is an increase in frequency, and if the relative motion is such that they recede away from each other, there is a decrease in frequency as observed by the observer...
Now its extension into light waves...
Consider a similar case with light waves...
If the source moves towards the observer, we have an increase in frequency of light waves which we term as blue shift.
If the source moves away from the observer, we have a decrease in frequency which is what we call as red shift.
Practically, we don't feel this effect because the speed of the relative motion between the source and the observer is usually neglible compared to the velocity of light waves.
This redshift doesn't necessarily take place because of the Doppler effect.
Consider a photon travellin away from the earth's surface, or, let's say a gravity well...its path wud be similar to that taken up by a projectile which slows down as it gains altitude by transfering its kinetic energy to potential energy.
But in the case of a photon, it cannot lose energy by slowing down as they are always considered to travel at 'c' . So we have to comprehend the loss in energy as a lowering in frequency of the photon waves, in other words, redenning of photons. This is termed as gravitational redshifting.
Here too, u have the gravitational blueshifting, which occurs when a photon falls into a gravity well.
If you are one of those techy guys looking for a valid derivation to support this theory, get some book relating to quantum physics...
So...the first thing you'll have to know in order to understand this concept wud be Doppler effect and its extension into light waves...
For those who are new to Doppler effect...
Whenever there is a relative motion between the source of sound and the observer, there is a change in the frequency of sound observed by the observer...
If the relative motion is such that the source and observer approach each other, there is an increase in frequency, and if the relative motion is such that they recede away from each other, there is a decrease in frequency as observed by the observer...
Now its extension into light waves...
Consider a similar case with light waves...
If the source moves towards the observer, we have an increase in frequency of light waves which we term as blue shift.
If the source moves away from the observer, we have a decrease in frequency which is what we call as red shift.
Practically, we don't feel this effect because the speed of the relative motion between the source and the observer is usually neglible compared to the velocity of light waves.
This redshift doesn't necessarily take place because of the Doppler effect.
Consider a photon travellin away from the earth's surface, or, let's say a gravity well...its path wud be similar to that taken up by a projectile which slows down as it gains altitude by transfering its kinetic energy to potential energy.
But in the case of a photon, it cannot lose energy by slowing down as they are always considered to travel at 'c' . So we have to comprehend the loss in energy as a lowering in frequency of the photon waves, in other words, redenning of photons. This is termed as gravitational redshifting.
Here too, u have the gravitational blueshifting, which occurs when a photon falls into a gravity well.
If you are one of those techy guys looking for a valid derivation to support this theory, get some book relating to quantum physics...
hey mate. thanks for the comment. and nice post :). keep it goin!
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