simpler way for non-math people to understand this is to place a large leaden ball on a rubber sheet suspended between four poles. The rubber sheet will sag from the weight of the lead ball, and if you spin a marble on the sheet it will circle the lead ball, just as the earth circles the sun. The reason is not that there is any attraction between the sun and the earth but that the earth follows the straightest path it can follow in curved space-time.