What is Dark matter, well I don't know at all but I have a theory.
I've read lots on the subject and since we still don't know what it is, I thought I'd give it a shot.
First I would like to remind you I have no formal training on the subject. So please take this as completely wrong, utter crap.

Let's start with one of the responses to the Large Hadron Collider at CERN smashing particles. Is it safe to smash particles? Answer is this happens all the time in space as particles from space crash into the earth, t
hey cause tiny black holes these black holes evaporate almost as soon as they are created. Ok I take this as a given and their right, and this is where my theory starts, black holes get created every time two particles collide at extreme high speed. The sun every now and then blasts out millions of particles into space and some of these particles crash into earth. As they collide they generate tiny black holes, these black holes get pulled apart by other heavier particles around them. The way I see it, if two big black holes came close together, the smaller one would get ripped apart by the bigger or larger of the two. This also would release all the matter which is held in the singularity as some sort of force. 
This energy would look as though it came from nothing from a single point, the singularity before the other black hole swallows up most of it, if not all of this 'dark energy'. So dark energy is energy released from a black hole being torn apart. It's not matter any more because not a lot of matter can fit in a single point. E = m c 2
Back to our particles, some go further travelling out into space. As some collide into a particle and with less bigger particles around the tiny black holes last longer, until some larger particle attracts it closer and rips it apart. This process screens out larger slower particles leaving only the smallest and fastest, luckiest particles to reach the outer reaches of the solar system.
If you imagine theses tiny black holes getting created as particle collide right out in the edges of the solar system and only where there is so little matter about that they can exist for any length of time and they do. They are found floating around filling up space between the stars and the galaxies. So many of these tiny black holes, like billions of bubble washing around between the stars surrounding the galaxies.
They are small and almost mass less but like bubbles they combine their masses to produce most of the mass in the universe. They hold together the large galaxies and cause one of the two colliding galaxies to lose shape becoming clustered galaxy.
So why wouldn't these tiny black holes combine and form larger bigger stronger black holes, well some do but not most, and as they do they begin to grow in mass they get heavier they get pushed closer to bigger heavier particles and evaporate. And why most don't is because they spin around, they are curvature singularities. As they get created the two particles hit but not all head on, most just off like darts in a dart board they can still hit the board and create a black hole but not a stationary one with a direct hit. They create spinning black holes.
They spin and push off or throw each other away. The same way our sun keep us the earth here fixed in space.
So I picture a universe with galaxies covered in tiny bubble black holes, they are being created and destroyed all the time. They are all trying to get to the centre but are forced back by the heavier object. They cover every object that has mass but as there are billions of them they tend to move to the object with the most pull. In spiral galaxies they fill the top and bottom of the doughnut-shaped ring. They extend out well past the outer edges of the galaxy.
These tiny black holes change in quantity every time these events like a super nova happens.

Then as a star explodes throwing out massive amounts of mass into this the bubbles of tiny black holes bursting billions creating billion but more to the point altering the balance of mass in the galaxy and creating dark energy.
- What affects does this causes, well it moves galaxies around propelling them this way and that.
- Another affect is the amount of light coming from other stars and galaxies is reduced; the tiny bubble black holes bend and filter the light. Which is a good thing, it means we may be closer to them then we think. Just like it takes photons thousands of years typically to get from near the core of the sun to the surface and only 8 minutes and 18 seconds to reach us on earth the same happens with light from the other stars and galaxies.
- So next you’re in a space ship heading out away from our galaxy into deep space you need to shake off these bubbles and reach deep space prepare to stop a little quick then you calculated because you may bump into that far away galaxy your flying too.
- Also don't panic about running into these tiny black holes the dust particles your ship attracts around it will burst any black hole bubble. Even the mass of your ship would cause them to evaporate.
So how do we tell if this is fact or fiction, I would say its fiction until proven, so how to tell it maybe plausible.
- Look at galaxies that interact, does mass move or has moved changing the dynamics, one becoming unstable as the other has more mass then before? When they are far enough apart for large bodies not to be drawn from one to the other.
- With the Large Hadron Collider at CERN smashing particles together, if they create a black hole how will it react with other particles, is it affected by gravity?
- Test how much light comes from a quite star as it interact with a larger body, like a small star in an elliptical orbit around a larger star free of dust clouds. Does the amount of light change as the star move in and out of interactive zones?
- Wait for VOYAGER 1 to get out passed the sun interactive zone, but will it have any of the instruments on board to detect them.

- Size of the universe, it's big, very big 150 billion light years wide and 13.72 billion years young. So this would mean in 13.72 billion years the outer bits have moved 75 billion light years, how can it be more than double 13.72 billion light years wide if you’re travelling at the speed of light? I say it's only 30 billion light years wide at the most.
The end
Added on the Thursday, 15/10/2008
Edited on the Friday, 29/01/2010
By Damien Huxley