Relativity makes no sense. When the planet comes close to the Sun and starts moving towards it, in a curved line due to curved space, they say that this explains gravity. But this does not explain why this curve in space would make the object move in the first place. For example, when you hold an object and let it go. It falls down because of gravity, but there is no force to initiate the pull according to relativity. There needs to be a force to pull it down, from the stationary position.