The ADD Theory: A Theory of Gravity

The original motivation for this ADD theory was to explain why gravity as a force is so much weaker than the other forces, something we call the hierarchy problem. We want to construct a theory where gravity is actually very strong, but it's diluted because most of its influence is kind of traveling off into dimensions of space we don't experience. And physicists like really heroically built incredibly precise laboratory experiments to test the force of gravity with ultra high precision and ultra short distances. But sadly, I guess, inverse square law held up. So it appears that there aren't any millimeter sized extra dimensions, although we can only put limits.