Would a space shuttle that travelled to a parellel universe that was in the past or present state of our world be considered a time machine? I have been debating this with a friend for a while for a while. He argues it does i think it doesn't.
Let me give you a example to illustrate why not . BM is sitting in a room with a cup o' joe on the table. Now, you have two choices (ok, a plenty more, but let's just approximate): to drink the coffee or not to drink the coffee. At this moment, the universe splits apart into two (mostly) identical universes: one where you drank the coffee, and one where you didn't. Let's take it further. Say, BM is a coffee addict, if he doesn't get his cup of coffee, he will die. So there is a parallel universe where you are dead/dying and one where you're healthy and alive. You can travel from one to the other (as long as you are alive), but that's not time travel. It's a completely another space-time continuum. Whatever you do there, it doesn't affect what happens in the other space-time continuum (which is a prerequisite of 'real' time travel).
sorry to inflict physics on those who are not interested
Let me give you a example to illustrate why not . BM is sitting in a room with a cup o' joe on the table. Now, you have two choices (ok, a plenty more, but let's just approximate): to drink the coffee or not to drink the coffee. At this moment, the universe splits apart into two (mostly) identical universes: one where you drank the coffee, and one where you didn't. Let's take it further. Say, BM is a coffee addict, if he doesn't get his cup of coffee, he will die. So there is a parallel universe where you are dead/dying and one where you're healthy and alive. You can travel from one to the other (as long as you are alive), but that's not time travel. It's a completely another space-time continuum. Whatever you do there, it doesn't affect what happens in the other space-time continuum (which is a prerequisite of 'real' time travel).
sorry to inflict physics on those who are not interested