Question

Is there anything that can block the effects or decrease the effect of gravity? Any experiments that tested it? Magnetism can be blocked and why not gravity?

Answer 1

Both magnetic and electric fields can be manipulated to be zero, but that is much more difficult for gravitational fields. The main reason is that there are two kinds of electric charge but only one kind of mass. That is not to say it is impossible. For example, there is a point between the earth and the moon where the field is zero, where the attraction to the earth is equal and opposite the attraction to the moon. But, in order to have any effect on the field near the earth, you need to manipulate giangantic masses. As far as we know, there is no such thing as "antigravity".