Is this dark energy/matter?

Question

Regarding dark energy and dark matter. It’s been a while but in my high school physics class I was taught that light energy was massless. However Einstein predicted and it has been proven that light can be deflected by gravity. It would then seem to me that electromagnetic energy must possess some degree of matter, possibly at the speed of light in a form we don’t recognize. Consider a star many light years from earth, we see light energy (or other energy) that has been traveling for billions of years. We detect only that which we see or that wich has interacted with other material to produce a detectable energy and then only the energy that is directed at us. I suspect that the amount of energy we actually detect would amount to a one about a mile to the right of the decimal. It would seem to me then that the vast majority of all the energy emitted by all the heavenly bodies that have emitted energy over the eons that the universe has existed will go undetected and is still zipping around out there and that is a lot of energy. Is it possible that this is the dark energy and dark matter we are looking for? It’s a rather wordy question but that is my question.

Answer 1

General relativity predicts a certain form for the matter distribution given by light, which is consistent with the signal travelling at the speed of light. This can be interpreted as a limit of particulate matter travelling at a speed approaching the speed of light.

Current observations of dark matter indicate that it has clustered in specific, stable orbits around galaxies and galactic clusters. This observation is not consistent with light speed travel, but rather with the dark matter being in a thermodynamically cold state.