Special Relativity

No mass kiss my Ass

An argument in favor of Light having Mass
"Or Special Relativity"

If light were composed entirely of Photons
Then "Light" can be
Said to have no mass
But...
Here is an extremely "Inconvenient" fact
There are other elements to light
Like Energy and her Sidekick
Momentum
And by definition Momentum is
The quantity of motion of a moving body
Measured as a product of it's 
Mass and Velocity 
That's right boys and girls "MASS"

Sunlight Pressure can give a Comet a tail That is Ten Million Kilometers long
I would call that 
Pretty God-Damned Fucking Massive

Note:
Humorous attempt at Levity
No one is seriously arguing in favor of Light having Mass