*Note: I will be using the words “dimension” and “universe” interchangeably here. If this is not correct some please point it out to me.
Thinking about interdimensional travel this morning on the way to work I suddenly came up with a really nagging thought. Supposedly, a universe is a closed system. The amount of energy that was present when the universe began is constant throughout. No energy can be created or destroyed, but with travelling from dimension to dimension this is exactly what one is doing. If I were to be able to enter another dimension I would be introducing energy into a closed system. For all intents and purposes energy would have been created from that universe’s point of view. If I would to take something with me when I left I would leave a void that that energy filled hence destroying energy.
Is this one reason why travelling from dimension to dimension is impossible? Has any Sci-Fi writer or serious researcher ever tackled this problem? And what would happen to our universe if energy were suddenly created or destroyed?
I suppose so… another reason that travelling between universes might be impossible might just be that there aren’t any other universes to travel to.
In order to travel there we have to interact with something that is, by definition, out of our reach.
A system is only closed if matter can’t enter or leave it, so I’d guess that if inter-universal travel was possible, we’d have to consider our universe as an open system. The total amount of energy/mass in all the universes combined should be constant though - at least until we find a way to go beyond that…
A dimension is a scale of measurement, including (and especially) directions of travel. While the definition of a universe is debatable, there really is no overlap between the concept of a dimension and the concept of a universe.
Where it gets interesting (at least to me, and if I understand the way of things more or less correctly) is that you can’t get out of the universe by travelling along any of the three spatial dimensions. In the same way, the universe is bounded in time at the beginning and at the end. There isn’t any “before” the universe or “after” the universe.
But if it were possible to travel along a different dimension - imagine a railroad built along a line that is perpendicular to length, width and depth, all at the same time. That, I suppose, might get you somewhere. Of course, if you travel even an infinitesimal amount along this railroad, you’ve left the universe.
Or put another way, you’ve made the universe an open system, so you won’t get a summons for violating conservation laws.
Or - and here this depends on the question, “What is the universe?” - you’ve expanded the universe by adding another dimension to it.
Possible to create a way to travel in a direction that just doesn’t occur in the universe? I’ll be garsh darned if I have any idea. I don’t see why not, but then again I don’t really understand why pi can’t equal 4.
I think ryoushi nailed it–if you can get there, then it ain’t closed.
Also, the Ame.Her.Dic. has
di·men·sion n. Abbr. dim. 1. A measure of spatial extent, especially width, height, or length.
u·ni·verse n. 1. All matter and energy, including Earth, the galaxies and all therein, and the contents of intergalactic space, regarded as a whole.
Why would you want to use “dimension” to mean “universe,” when you can just use “universe”?
I guess my brain was warped by all those cheesy Sci-Fi movies I used to watch as a kid where they travelled from the “3rd Dimension” to “4th Dimension”.
Very well, please replace dimension with universe in my OP. And thank you for the replies.
Dimension sounds so much cooler. Didn’t you ever watch Teenage Mutant Ninja Turtles? <Krang voice>Shredder! We’ve got to get the Technodrome out of Dimension X!</Krang>
