I ' m not an expert but I ' ll take a shot . Einstein ' s theory of relativity has explained gravity as we know it for a long time . Objects effect space the same way a heavy ball sitting on a trampoline would effect other objects on the trampoline . The heavier it is , the more it warps the trampoline to pull other objects toward it . If light , it would only warp a small amount , so an object would not pull toward it unless they were very close together . So for example , the Earth warps enough space to pull all of us on top of it constantly , but only enough to hold the moon in orbit further awayWhat scientists have struggled to explain is why relatively doesn ' t work at the particle or quantum level . There , I ruined your day .