Astrophysically speaking....

First, the big picture......

This 'dark matter' seems more like 'invisible matter' because we can't see it directly, but rather only by its effects.

Not long ago, our scientists introduced us to the Higgs boson, dubbed by the media as 'the God particle', a nickname Higgs and other physicists strongly dislike. But what if this 80% of the universe known as 'dark matter' is some sort of evidence of God? What then?

And going back for a moment to 'Uncle Albert' and his 'E = MC squared' theory,
everything in the universe is in motion - even grandpa in his lounger watching TV, because the earth is, for example, moving in eight directions simultaneously and all that other stuff out there is whizzing around and flying off in various directions as the universe expands into something we'll call The Void for want of a better definition.

So, if energy equals mass times velocity squared, then masses in motion can be considered as energy. And there are different different kinds of that. The 'Big Bang' (the original production, not the TV show) was one kind. The steam generated by heating water is another kind. And maybe 'dark matter' is some other kind that ties the whole thing together and gives it somewhere to act and react. I think what I'm trying to say is that along the space/time continuum, there is only a very limited range of 'frequencies' or physical properties that are detectable by us and beyond that lies the vast majority of that space/time continuum. And just because we can't 'see' it, it doesn't mean it isn't there, interacting with what we do 'see'. And as our technology improves, we're able to detect a little more, a little further, along that continuum. But we still aren't able to make sense of enough of it to explain the big questions, like "Where did it all come from?" or "Where is it all going?" 

Some things, like peace in the Middle East, seem to be perpetually beyond our grasp. And if we can't solve a problem like that, how can we hope to understand something like 'dark matter'?