Dark Energy & Light: The Mystery

[ravisastry]

Hi,

these days. I am reading a lot about dark matter and energy in news papers. i came to know that dark energy/matter constitutes almost 75% of energy of universe ? can it be possible tat, this dark energy is the same as electromagnetic radiation emitted in this universe since big bang ?

 

[nicksauce]

Nope.

We know very well how much electromagnetic radiation is the universe by measuring the temperature of the CMB. It is about 10^-5 of the density of the universe. There is no plausible mechanism whatsoever to create 100,000 times more radiation. Furthermore, the dark energy acts completely different than radiation. Dark energy accelerates expansion, whereas radiation would decelerate it.