There have been much talk about how powerfull Rikudo Sennin really was so here's a little teory about it.
When Nagato used Shinra Tensei on Konoha i think (not completly sure) that it was bigger than the Chibaku Tensei he used against Naruto later. So if that's true then in theory Rikudo Sennin should also be able to create a Shinra Tensei bigger that the moon. I know it sounds a bit crazy but if he could then he would in theory be able to push planets, and yea of cause he would die if he pushed the planet he was on cause he can't breate in space. But if he really could do that, then as a suicadal attack he would be able to push a planet into the sun exploding the whole solar system! And yea this is probaly just bullshit but you got to admit that it would be cool