Oh, science. Sometimes you confuse me.
That is an example of something I will never, ever, say. Science makes a world of sense. Unlike some laws humans have created, the laws of gravity
a) Physically cannot be broken, no matter how hard you try or how rebellious you feel, and
b) Aren’t completely stupid and meaningless. Because if you don’t follow the laws of science – the basic laws anyway – you literally cannot be real. I know sometimes people use literally to exaggerate, (i.e. “I would literally die!) but I mean literally, as in you physically cannot exist in the Universe!
Sometimes I don’t want gravity to be a thing, but actually, no, I don’t, because if gravity didn’t exist we would not, would never, exist.
That would be pretty bad.
And then there’s spacetime..wait a second! Why is there a squiggly red line under spacetime? You don’t get to squiggly red line Stephen Hawking!
Never mind, they had the squiggle under lightsaber too. They’re just not very smart.
Anyway, spacetime. Stephen Hawking describes other theories as a railroad, a linear construct, but he goes on to say time is more like multiple tracks that can circle back to any station at any time. He also says that time and space are tangled together, and you can’t effect one without effecting the other as well. The Doctor, (from the BBC series Doctor Who) describes it as ‘more of a ball of wibbly-wobbly….timey-wimey…stuff.’ which is essentially the same concept put more whimsically.
Therefore, if you were to, theoretically, create a time machine, it would also have to be space machine, relatively, therefore figuring in the fourth and fifth dimensions, space and time. This purely hypothetical machine ( Time And Relative Dimensions In Space ) would warp space and time around it.
As for interdimensional travel, there would be a possibility of aforementioned travel assuming you mean dimensions in the sense of the multiverse theory, which proposes multiple Universes, (a delightful oxymoronic phrase) and not the dimensions in the sense of the second and third dimensions, which are used most often in Mathematical equations and made a delightful Doctor Who episode with two-dimensional beings and the T.A.R.D.I.S shrinking(though not on the inside!). If you’re talking about the multiverse theory, which also has been used in a Doctor Who episode, this implies there are doors, gateways, or some other form of travel. The machine mentioned must either be able to locate and withstand the pressure and energy of such a door, or must be able to create a door. Alternately, the ‘fabric’ between dimensions could be portrayed as a sheet of paper rather then a wall, and in that case you must find a rip, or you must be able to procure the force necessary to create a hole yourself.
How are the multiple dimensions located relative to each other? Are they too in a ball, so you can go from Dimension A to Dimension B to Dimension X, then back to A again? Or are they straight, so they can only go A to B to D, etc.
The multiverse theory proposes the Universes are the same as our own except for one or more crucial differences, like Albert Einstein became the president of Israel, or Isaac Newton decided he would stay inside and read.
Therefore, we can assume most of these universes are governed by, basically, the same laws as our own, because these laws are required to sustain life. If spacetime is a constant across the multiverse, it is to be reasonably assumed that, naturally, the multiverse takes the same shape as spacetime, because a universe includes space, time, and matter. This means, logically, you can go from A to B to W to X, and you won’t have to go through twenty-four dimensions to get back to A again. Instead the multiverse acts as a spherical grid, where the intersections are the dimensions. You can go from one side of the sphere to another with enough force, as well as the intersection next to you.
But what of time? If you traveled from your Earth in A, then to B, W, and X, when you returned to A, how much time would have passed if it took a year? In this scenario spacetime is a constant through the universe. Think of a infinite clothesline. Each piece of your laundry is an individual universe. The clothesline is spacetime. The clothes themselves aren’t touching outright, but all of them are touching the clothesline. If you were strong enough, you could go to one to another, with different colors and shapes and sizes, but it will always be the same clothesline.
But if you took an accurate clock on your Alphabet Adventure, it doesn’t mean it would match up with an equally accurate clock when you returned to Earth in Dimension A. This is part of Einstein’s Theory of Relativity, called personal time. This states that there is no universal clock as previously believed, but instead time was warped depending on the speed of the object moving. This means your time machine, unbelievably powerful, would also have to move very fast. You would still be around the same age, and your best friend will have had children already!
Also on the subject of the multiverse theory is timelines. The popular theory is that every decision creates an alternate universe where a different choice was made, it was made in a different way, something (whether as uneventful as tripping or something as drastic as a fistfight) prevented you from making the choice, or the universe catastrophically ended. These, and an infinite amount of other scenarios, have happened in infinite dimensions in an infinite amount of ways. For example, in another universe, you never read this. In another, I never wrote it. And in yet another, we’re are all shrimp-people. Yes, shrimp-people. It’s possible, especially with infinity.
End of Part 1