Dark Matter is bad science.
Let me see if I got this right: a bunch of scientists wanted to measure the mass of the universe. They did a bunch of calculations and then compared the results of the calculations to the observable universe and found that they didn't match and that the universe had much more gravitational pull than their calculations said there should be. So the scientists then said: "Hey, our calculations can't be wrong - the universe must be wrong." And they came up with the idea of some invisible matter to compensate.
Their calculations were supposed to conform to the universe, the universe isn't supposed to conform to their calculations.
Bad, bad science.
I will be utterly shocked if they ever completely confirm that Dark Matter exists.