# What dangerous side effects might occur when using a bubble of spacetime to enter hyperspace? [closed]

I'm creating a fictional hyperspace to enable FTL travel. It's sort of a mix of Star Wars, Star Trek, Halo, and probably a bunch of other stuff. I've run into an aspect of it that either requires some handwaving or a bit of math that's beyond my understanding. It goes something like this, please bear with me:

Hyperspace is perpendicular to our normal spacetime. As you go "deeper" into hyperspace, coordinates get compressed. Imagine our spacetime represented as a square plane and hyperspace as an inverted pyramid below it (or a disc and a cone, if you like). Since all points eventually converge at the "bottom", if you can go down into hyperspace and travel a bit, when you come back out you will have moved father than normal and faster than light (effectively). This compression occurs in smooth gradients, not distinct layers like subspace in Star Trek.

Like Star Trek though, you need a field that creates a bubble around your ship. This makes an area of normal spacetime that protects your ship. Then you can push into hyperspace with this bubble and manipulate the shape of the bubble to move around in hyperspace. Hyperspace wants to push you out (or keep you out), and gravity wells magnify this effect. So you need enough energy to stay in and you need to plot a course that avoids gravity wells.

I'm not asking about the energy requirements though, because I have a fictional power generator that we don't worry too much about.

Since you naturally pop out of hyperspace near gravity wells (or even if your drive fails), the main dangers with this drive system, in my mind, seem to be regarding the field that makes the bubble. Anything contained within the bubble goes into hyperspace, which allows for stuff getting cut in pieces, like what happens in Halo 2 when the Covenant ship jumps while it's still over the city (It brings chunks of buildings with it into deep space).

The field that makes this bubble in my fictional universe can vary in strength from nothing (off) to a level that allows for the transition to hyperspace, then beyond, until you don't have enough energy to go any deeper into hyperspace. I think that these bubbles repel each other (kind of like magnets), such that two ships in hyperspace would not collide. I also think there must be a gradient of some kind between normal spacetime and hyperspace, however slim, at the edge of the bubble.

Given all that, my questions are:

1. What might happen to matter at the inside and outside surfaces of the bubble at the moment of transition?
2. Could there be dangerous effects even before the transition to hyperspace, as the field strength is increasing?
3. What might happen to propellant expelled/ignited if the ship fired its conventional engines while inside the bubble (or any other matter contacting the bubble, really)?
4. Might there be any dangerous radiation inside or outside the bubble, especially due to any matter caught in the transition?
5. Does it make sense that the bubbles would repel each other (does it seem internally consistent)?
6. What visual effects might there be to an outside and/or inside observer (especially during transition)?
7. Any other potential dangers from creating or collapsing this bubble?

Bonus/Epic Fail: Are these questions even answerable with my description of hyperspace?

Edit to attempt to make things less broad:

Based on a4android's answer I'll refine the definition of the bubble by saying that it is impermeable in both directions (hopefully lending credibility to the idea that bubbles repel each other). Also that you can't see out of it, probably for the same reason.

So really the main concern is: what happens to matter when it's sheared at the edge of the bubble as the ship enters hyperspace? (For example, might it become superheated, converted to energy, etc.) Are there any known rules of physics that might inform my description of the effect, or do I just make up whatever seems fun?

I know this isn't hard SF by a long shot, but I like it when the answers at least seem to be based on what we know about physics. I also know that's a bunch of questions rolled into one long post, so I appreciate any help you can give.

• First off, you're asking 7 (+1 bonus) questions together, which makes the question too broad. Secondly, you have created your own hyperspace system, to which we cannot possibly know the physics behind, which makes the question unanswerable - if you're looking for a list of possible outcomes/theories, this is the wrong place to ask, as that would make the question Primarily opinion based. So, all in all, I can only answer your bonus question: No, we cannot answer any of those questions. – Aify Jul 15 '17 at 5:55
• A bubble can burst? – Alexander Jul 15 '17 at 6:33
• I think 1) is worth debating and I do believe it is answerable within the definition of an answer most people here have. I'm just lazy and do not want to make a page-long post with pictures and all of that. 2-6) sound like you can just make up whatever. 7) Is nothing but a question if there should be more questions. – Raditz_35 Jul 15 '17 at 7:52
• There is no matter in space to be sheared. For the stray molecule that is, turn to quantum physics in which even atoms do not have a fixed location anyway: So you can claim the shell appearance constitutes a measurement, and collapses the waveform of any atom, just like any normal observation by lab equipment, and forces it either inside or outside the shell. Note that the two slit experiment has been shown to work even with entire molecules; like a 60-atom buckyball. If buckyballs have no fixed location, there are no atoms that have a fixed location. Take advantage of that. – Amadeus Jul 15 '17 at 23:21
• So, "As you go "deeper" into hyperspace, coordinates get compressed" - spacetime coordinates getting "compressed" is indeed just simply what happens on, eg, Earth. (ie, "gravity".) One the near versus far side of the moon, coordinates get compressed a bit - hence tides. Coordinates are compressed a tiny bit more at your feet than at your head. (There's tiny tidal pull between your feet and your head.) "This compression occurs in smooth gradients" So, there is a difference between your feet/head prow/stern - that's tidal force. – Fattie Jul 17 '17 at 11:15

This model of hyperspace, with coordinate compression increasing with depth in hyperspace, is quite good for fictional faster-than-light travel. Full marks for an elegant and well-behaved system for accomplishing FTL travel in a fictional setting. Your questions concern the behaviour and properties of the bubble of spacetime generated by a field that enables spacecraft to enter and exit the hyperspace. The bubble protects vessels in hyperspace and enables its motion there.

By and large, these properties of the bubble can be decided by yourself as its author to be anything you want them to be. However, it is possible to apply some scientific imagination to make some reasoned propositions for what is does and how it behaves.

1. What might happen to matter at the inside and outside surfaces of the bubble at the moment of transition?

There are two possibilities. Matter trapped at the surface will either remain in normal spacetime or be dragged down inside the bubble into hyperspace. If the matter remains in spacetime this might prevent the spacecraft inside its bubble from entering hyperspace. Considering the bubble is generated with considerable power the matter could be sheared off and stay inside the bubble.

2. Could there be dangerous effects even before the transition to hyperspace, as the field strength is increasing?

This seems imponderable because it depends on the nature of a fictional field and whatever effects are associated with its strength. However, since spaceships survive intact inside the bubble as its strength builds, then it is not unreasonable to assume that this also applies any other matter inside the region of the field.

Any other dangerous effects could arise from how the field interacts with matter and energy or even the quantum vacuum.

3. What might happen to propellant expelled/ignited if the ship fired its conventional engines while inside the bubble (or any other matter contacting the bubble, really)?

This depends on whether the surface of the bubble is penetratable or permeable and this permeability and penetration works either one-way or in both directions. If the bubble is an impermeable barrier to propellent or any other matter trying to exit the bubble. Then obviously this will be trapped inside the bubble. This could be uncomfortable and inconvenient for a rocket exhaust with nowhere to go. Furthermore, there will be no way for a ship to exhaust heat, which will be a rather serious problem.

On the other hand, if the bubble is impermeable to matter and energy entering it, but allows matter to exit it, then the vessel won't drown in its our exhaust. But if the bubble is perfectly impermeable, then nothing enters and nothing leaves. Again a spaceship will have problems with its own expelled reaction mass.

4. Might there be any dangerous radiation inside or outside the bubble, especially due to any matter caught in the transition?

Only if matter trapped in the surface of the bubble undergoes a transformation into energy. Other possible sources of radiation could include virtual photons and particles emerging from the quantum vacuum and being trapped inside the bubble. Effectively this like Hawking radiation being created at the event horizon of a black hole.

Radiation of this kind doesn't have to be a normal feature of the bubble. It might only be something that happens when the field strength, for example, either exceeds or falls below some critical level. This will be left as an exercise for the author.

5. Does it make sense that the bubbles would repel each other (does it seem internally consistent)?

Definitely yes. Most so, if the bubbles are impenetratable such matter and energy cannot enter them while in hyperspace. Possibly, the nature of the bubbles themselves might make the bubble surfaces impenetratable to each other.

6. What visual effects might there be to an outside and/or inside observer (especially during transition)?

An outside observer may simply see the bubble vanish as it enters hyperspace and pop into view as it exists. What an internal observer sees depends on whether normal spacetime is observable while in hyperspace. If spacetime is observable, then the distances between astronomical objects will appear to contract with coordinate compression. This will make navigation easier too.

7. Any other potential dangers from creating or collapsing this bubble?

This will be entirely depend on interactions between the field, the bubble and matter, energy and spacetime itself. This also may depend on how smoothly the bubble is created or collapsed. For example, the surface of the bubble might be loaded with a massive amount of energy, and as it collapsed this energy could be released. So a spaceship could emerge from hyperspace accompanied by a massive blast of radiation radiation and particles. For the safety of the vessel all this energy will propagate unidirectionally away from the spaceship. Any backscattered radiation might be a problem.

Bonus/Epic Fail: Are these questions even answerable with my description of hyperspace?

They can be answered with a combination of commonsense, logic and scientific imagination. Any flaws in the reasoning applied here will soon be ferreted in the comments.