Dark matter Or anti-light

To every force, there is an equal and opposite force, A truth. We've are all told at school. A Star/Sun emits light so powerful it can push a planet into a different orbit. As a sun is round then these forces balance out and the Sun remains in.the same place, That doesn't explained the "opposite" force. Is this what Dark Matter is? The attraction that holds galaxies and solar systems together that gravity doesn't explain n