Remarkably, it turns out there is five times more material in clusters of galaxies than we would expect from the galaxies and hot gas we can see. Most of the stuff in clusters of galaxies is invisible and, since these are the largest structures in the Universe held together by gravity, scientists then conclude that most of the matter in the entire Universe is invisible. This invisible stuff is called dark matter. There is currently much ongoing research by scientists attempting to discover exactly what this dark matter is, how much there is, and what effect it may have on the future of the Universe as a whole. 
In astronomy and cosmology, dark matter is hypothetical matter that does not interact with the electromagnetic force, but whose presence can be inferred from gravitational effects on visible matter. 
Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space. It has been noted that the names "dark matter" and "dark energy" serve mainly as expressions of human ignorance, much like the marking of early maps with "terra incognita." 
In choosing the name "Dark Matter" for this exhibition, I reflected on the 'invisibility' of dark matter, yet its powerful effect on the rest of the universe. In much the same way, our perception of, and therefore our reaction to, the environment around us is filtered and affected by many factors we are not aware of. My goal is to present the viewer with some 'dark matter' (as defined by me) and evoke / provoke a response. Much of this material would be passed by or filtered out by someone walking the same paths I did. By presenting it in this manner, it forces the viewer to consider 'what else' might they be missing.
My interest in photography began in London, Ontario in the early 1970's. I soon began processing my own film and printing my own work. I enjoyed this for approximately 10 years; most of the black and white images are from that period.
When a new interest developed, I abandoned photography and struck off in a different direction. The lure and passion have always remained, and only recently have I become involved again in it, although now it includes a digital format.
"There was a time when I thought I should be like everyone else.
Then there was a time when I thought everyone else should be like me.
Now, I just think."
Amer Neely - [ca. 1974]
 Goddard Space Flight Centre - NASA