Why dark matter is dark but not atoms

Dark is 'dark' because it is formed from dark energy a hypothetical type of energy I believe.

 

Sorry I meant "dark matter is dark"

 

No dark matter and dark energy have nothing to do with each other. The term dark merely infers that little is known about the two. Dark matter is considered a non baronic weakly interactive particle. The only known force interaction is gravity. Hence why its so difficult to detect
Dark energy is the energy that is accelerating expansion.
Dark matter and Dark energy is covered in numerous posts. I would suggest looking through the threads.

 

Well, not quite. The 'Dark' in 'Dark Energy' is precisely this -- it just means we don't know what the heck it is. The 'Dark' in 'Dark Matter' however tells us that whatever it is, it doesn't interact electromagnetically (hence dark).

There's a lot of speculation and misinformation going on here, and I can't help but think that a simple trip to wikipedia would clear a lot of it up: http://en.wikipedia.org/wiki/Dark_matter

 

Good point It was late when I typed that and I was half asleep. Talk about addiction lol