What would happen if you left Earth and then it was destroyed? (Potential energy and thermodynamics) So I did some research on magnetic generators and what kind of energy magnets loose when they move something. Turns out magnets loose potential energy (you need to expend energy to get the object moved closer to or further away from the magnet again,) similarly to how the energy used to get something into space becomes the potential energy stored in the distance that object can then fall. So then I thought, “what if I deleted or blew the Earth up after spending energy to get away from it". So what would happen if I did that?
 A: "Deleted" and "blew up" are not the same thing. If you could cause the Earth to explode into a symmetrical, expanding cloud of countless billions of fragments (i.e., if you "blew it up,") then that cloud still would have the same mass as the original Earth, and it still would have the same center of mass. So long as you and your spaceship stayed outside of that cloud, you would feel no change: The gravitational field outside of the cloud still would be the same as the Earth's original gravitational field.
If you could cause the Earth to simply vanish, then you would be violating the laws of physics unless you could account for where all of the Earth's mass and energy went.
A: You might be interested in the shell theorem
This way, with a thin shell and an opening, you could quickly and sharply change applied gravitational force on your space ship by going through the opening in the shell.
A: If you could delete the Earth, that would cause the concept of gravitational potential energy to be quite problematic, which is one the reasons why the conservation of mass is considered to be a solid law (there's also other issues such as Noether's Theorem).
