I'm not a mathematician or physicist so please don't ask me difficult questions :smile: . But I think this: 'An alternative to dark matter is to suppose that gravitational forces become stronger than the Newtonian approximation at great distance' (http://en.wikipedia.org/wiki/Dark_matter)...
Hi, I'm new and I wonder if this will explain the pioneer anomaly. I think of the universe as an expanding hypersphere. Maybe gravity goes out to the 4th dimension and therefore it takes a 'shortcut' to voyager and slows it down more than calculated. I hope this makes sense to you.