Figuring out charge and current densities to determine size

[KickLaBuka]

Hi. It's such a relief to get some answers. Background. BS in Physics, Scott's Electric Sky, Ratcliffe's Heresy, Smolin's Trouble, done a lot of dreaming, and decided to spend a overstayed welcome with ask the astronomer at space dot com. Now I have some questions. I understand electricity and magnatism, but I do not know how the fundamental measurements we can catalogue are used as tools. What correllations do we have between the flux of light received, arc angle of the galaxy, and redshift of the hydrogen line, translate to absolute charge density, absolute current density? Sorry, I haven't looked at other posts; I'm sure this gets asked all the time. How is temperature measured and absolute temperature calculated? My guess is that temperature depends on size, charge density and current density.

Thanks, and sorry if I've asked the most repeated questions in this site. It took a while to get registered and I'll read afterwards.
-KickLaBuka