There's a lot of hype around time travel into the past or into the future using blackholes or wormholes. But's its just hype created by a lot of people who want to sell you their books. The goal of this post is to summary my previous post and to highlight those aspects of the previous post that show why time travel is impossible (as depicted in sci-movies or as discussed by astrophysicts such as Richard Gott or Kip Thorne.)
Here's a short summary:
(1) We live on a wrinkled 3D surface of a 4D sphere.
(2) The 2nd Law of Thermodynamics states that there is no way to give a particle enough energy such that it has enough mass/energy to curve space-time enough to go back to the Big Bang.
(3) Time travel is impossible. Even if you give a particle enough energy such that it is locally further back in time than its surrounding environment, as soon as you de-accelerate the particle back to normal speeds, the particle goes back to being at the same radius (time) as its surrounding environment.
(4) When you account for acceleration and de-acceleration (i.e. General Relativity), the Twin-Paradoxes and the idea of Time Travel go away completely. Therefore, when we teach Special Relativity to students in the class room, it's important to simultaneously time some of the basics of General Relativity.
(5) In the long-run, growing life is the best and fastest way to generate entropy and to expand the radius and surface area of the universe. Culture grows, music expands, art thrives, and mathematics dazzles while we expand life from Earth to other planets. It's a win-win situation for everybody. We live into an unknown future, with only the past as a rough guide on how best to grow life and expand the universe.
Here's the longer summary of the previous post: