Hi, new member here. I am not a scientist, so please do not assume for one moment that I have any idea that I know what I am talking about.
I am now in my 50s. I recall that when I was going through High School and briefly looked at the history of astronomy there was some point in time, be it classical, medieval, or earlier, when one school of scientific belief thought that the universe was not primarily empty space. That is to say it was believed that the spaces between the planets, moons, stars and so forth was filled with some kind of undetectable substance or solution.
The problem is that I cannot recall what that undetectable substance or solution was called. It nags at my brain every time I read a reference to dark matter or dark energy, but I simply cannot recall what it was called.
Can anybody here help me out ?
