In short, Dark Matter is an invisible 'glue' that binds the universe together.In astronomy and cosmology, dark matter is matter that is inferred to exist from gravitational effects on visible matter and background radiation, but is undetectable by emitted or scattered electromagnetic radiation. Its existence was hypothesized to account for discrepancies between measurements of the mass of galaxies, clusters of galaxies and the entire universe made through dynamical and general relativistic means, and measurements based on the mass of the visible "luminous" matter these objects contain: stars and the gas and dust of the interstellar and intergalactic medium.
In other words, Lucas was First.The Force is a binding, metaphysical and ubiquitous power in the fictional universe of the Star Wars galaxy created by George Lucas.
But wait, there's more....
In other words, it's a destructive force that's tearing the universe apart, which sounds an awful lot like....In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe.
The Dark Side (of the force):
I'm surprise Lucas hasn't sued the astrophysics community for copywrite infringment.The dark side is portrayed as the evil aspect of the Force..... th mystical energy which permeates the universe.