Modern human physics is aware of several forces, one classification scheme listing them as the nuclear force, the electromagnetic force, the strong force and the weak force. There have been hints of other forces at work, I’m going to describe a very basic notion of a “fifth” force (or third, or sixth – depending on which classification scheme you use).
This force relates to dark matter and dark energy indirectly, but is not actually either one of these. It is the force which propagates throughout the cosmos in real-time, the force you will need to learn about in order to be able to make real-time observations of the current cosmos even at great distances.
Different waves propagate at different rates. The variant of wave in question was dominant in the cosmos from the moment of the Big Bang until the period of inflation had begun churning to a rapid and grinding halt, at which time it became one of the weakest forces. It is weaker than gravity, even, which is why it’s so hard to detect. It begins to dominate again in regions where there is little-to-no mass present over distances long enough to make gravity from the nearest objects relatively irrelevant. Your best chances of being able to detect it are in deep space, as far away from any significant gravitational source as you can get in any reasonable amount of time.
This force is also one of the last components you need in order to produce a functional stargate, as it is present everywhere at once.
I believe you should be noticing this force soon with certain unexplain “drifts” in the trajectory of certain deep-space objects. It’s not something you can really see, though, until you’ve been tracking an object for a fairly long time. One of the Voyagers would be a good candidate – analyze their trajectories for any unexpected shifts and that should provide your first evidence.