It’s got to be somewhere...
No it doesn't. This is the latest example of physicists saying "trust us, we're smarter than you" without any evidence to back up their claims. Gravity has a multiplying effect in planetary and stellar motion, so it is the simplest answer (Occam's Razor). They may be correct and there is a substance called "Dark Matter", but for a collective group of people who shun the thought of an Almighty God, they are rather hypocritical to tell us to just have faith.
Higher dimensions?