Large extra dimensions
In particle physics and string theory (M-theory), the Arkani-Hamed–Dimopoulos–Dvali model (ADD model), also known as the model with large extra dimensions (LED), is a model framework that attempts to solve the hierarchy problem (Why is the force of gravity so weak compared to the electromagnetic force and the other fundamental forces? ). The model tries to explain this problem by postulating that our universe, with its four dimensions (three spatial ones plus time), exists on a membrane in a higher dimensional space.