Imagine you have a sheet of stretchable fabric. The Sun placed on this sheet
causes a "bowl" to form. This is akin to a warp in space (in reality, the warp occurs in a
4th dimension). If an object has enough kinetic (orbital) energy, it can orbit the sun and
not fall in. Frictional losses of anything rolling around on fabric
would cause it to spiral in, but in Space, there is very little, if any, friction.
Higher density objects placed on the sheet increases the warping of the sheet.
A black hole is a body so dense, its mass so tightly bound, its surface gravity
does not allow light to even escape. In this metaphor, it is like a tear in the fabric.