hypothetical hyperspace stuff for that book I mentioned earlier

[Archabacteria]

Original thread is somewhere down there.

Basically, for a part of the book, the main method of interstellar travel involves 'phasing' into an alternate universe where c=10 trillion km per second (incidentally, I decided after knowing this, but rather randomly and not based on any logic, that the night sky would be almost white due to the light coming in from everywhere- feel free to say that this is completely inaccurate) and I wanted to know what this would change between universes besides the speed of light being much higher, such as other forces being weaker or stronger, or, put another way: what would have to change for light to go that fast?

As for how that makes a difference in how fast they can go, I have some other hypothetical stuff that somehow manipulates gravity fields to achieve acceleration. Don't ask how. And yeah, they can only accelerate and decelerate when fairly close to a massive body.

 

[Eagle1Division]

C, it's a constant, and I get a feeling all your electronics would instantly fry...

 

[Archer]

A universe in which the speed of light was instantly increased (by what ever power you want to use) would be functionally indistinguishable from our own. Light would still travel one plank length in one plank time as observed from within this new "universe" (all non-dimensional constants would remain the same.)

In other words, even if the speed of light were increased dramatically, you would still measure the same amount of time as you pass from point A to point B since your measure of the passage of time, and the distance between the points would be altered in proportion to the new value of C.

Reference: Michael Duff (Comment on time-variation of fundamental constants)

 

[Archabacteria]

That's useful to know. So I don't have to worry about electrons going faster or gravity being stronger or things like that.

Now with the speed of 1 average light year a second as the C, what percentage of C am I going at if I leave a planet orbiting a star 18.79 light-years from Earth and it takes me five months to get there? When originally coming up with the amount of time it would take to get places I came up with large enough numbers that they wouldn't have to accelerate the whole time. If anyone thinks I can go faster without breaking anything, go ahead and say so.

Also, I'd like to know the amount of relative time it took from a stationary reference on the planet vs the ship's clock. If you need any more numbers for that part, I have rotation period and revolution, in our hours and days.


('day' length (encompasses both day and night, the term is just my shorthand for the rotation period): 32 hours; year length: 2-- days (lines because I still haven't figured out the orbital characteristics well enough to calculate anything, but I'm pretty sure that it's quite a bit closer than Earth is to our sun, but not as close as either Venus or Mercury. It's a K0V star and I don't have access to climate data anymore- have to buy a program.)

 

[jthill]

e=mc^2, right? So I think if you up c, either the mass drops or the energy content spikes -- by a factor of 1,000,000,000,000,000,000,000,000, 1e24. That's a yotta difference. The earth would weigh as much as a large-ish cat. The sun would weigh less than a supertanker. No idea what else would change in consequence, either that way or the photons-hit-like-bullets alternative.

(added by edit: yeah, I think that paper's point isn't that changing c wouldn't change anything, but that the true nature of the change would be to underlying ratios, that the math permits rewriting that as different changes to other constants. They're criticizing a paper claiming that black holes could distinguish a change in e from a change in c by pointing out that mathematically they're equivalent statements. I'm not a physicist so I may be misreading it, but the point seems straightforward enough that I think I understand)

 

[Archabacteria]

Photons hitting like bullets would be fine- shields would hold for a few weeks and then they would drop back into normal space to recharge. Of course, if they're any faster than say, a railgun in velocity, then there might be a problem.

As well, with things weighing a lot less, there's the difficulty in getting an orbit.. Or would that be fairly consistent, since everything's mass is less?

And another thing of an idea I had was that if they return to normal space at higher than c, the ship would reduce speed to whatever percentage they were at in the other universe's reference, with the rest of the energy being shed off as tachyons. Possible or more likely to kill everyone for a good radius?

 

[jedidia]

That's useful to know. So I don't have to worry about electrons going faster or gravity being stronger or things like that.

The trouble is that, subjectively, you wouldn't go any faster after all...

The trouble with alternate universes is: If you want travel in one to mean travel in another, they have to be linked in space and time (otherwise departing from one universe could result to insertion in the other universe at any place and time, which is not what you'll want). So they're not as parallel as one might think. However, serious differences like different fundamental constants (like the speed of light) beg the question of how such a link is supposed to exist, as the phenomenae of time and space are pretty much linked to that (or vice versa, who knows...).

So your first giant handwave (apart from a parallel universe existing at all) is a parallel universe that is linked with ours in space-time yet has different physical constant.
If you handwave this, you're still left with the above problem: On falling back to the "real" universe, you might indeed have crossed a significant stretch of way in not much time passing. However, in your parallel universe you won't have expierienced this short. You'd expierience it as the same time as it took you to reach the same point travelling in the real universe (which again begs the question of what kind of link could possibly exist between two such universes, as the passage of time is obviously not consistent. Then again, the passage of time isn't strictly speaking consistant within a single universe, but I could imagine that you'll get some causality problems).

At least that's what's falling out of my brain when thinking about the topic, it doesn't mean it's accurate... But I'm pretty sure it's either this, or your brain will explode from overheating upon entering the parallel universe, never mind the electronics. Choose your destiny!

 

[T.Neo]

A problem I see here is the fact that if you elevated c, you'd still need to travel extremely fast to get anywhere effectively "faster than light". And that is extremely demanding; just accelerating up to 0.9c is demanding, and it'd still be demanding even if you didn't have relativistic effects (they make things a bit worse at that stage; the faster you go, the more relativistic effects... affect things).

An easier option might be to somehow slip into a universe that is smaller than ours but still somehow linked, so you'd travel say, half a lightyear in the other universe, and travel one lightyear in our own. You would be going far slower than light, but still arrive at your destination faster than a beam of light would.

 

[Archabacteria]

An easier option might be to somehow slip into a universe that is smaller than ours but still somehow linked, so you'd travel say, half a lightyear in the other universe, and travel one lightyear in our own. You would be going far slower than light, but still arrive at your destination faster than a beam of light would.

This sounds much better. I'm still between this and wormholes, acknowledging that making one takes a lot of energy and perhaps a dash of exotic matter. In fact, I was considering having wormholes later be the staple technology for large distances and the other system for relatively short distances of say, Earth-moon.

 

[T.Neo]

Well, one of the advantages of wormholes is they may actually be credible in reality, and out of all FTL concepts, they probably seem to be the best in terms of actually maybe possibly potentially working. They do have a lot of problems, such as needing to be very massive, requiring exotic matter, needing to be placed far away from other gravitational sources, and they need to be physically shipped to a destination at STL speeds before you can travel through them.

Maybe part of the magic of your "hyperspace" is being able to transport wormholes through it at effective FTL speeds...

Either way, if it's (relatively) easy to travel through hyperspace, then it tends to become a preferred option, rather than bothering with gigantic and problematic wormholes.

If you want to go at FTL speeds to the Moon, you'd be wanting to go extremely fast. At the speed of light travel time to the moon is on the order of seconds. Any powerful enough drive (and if you're building wormholes and travelling through hyperspace, you should have extremely powerful drives) should get you to the Moon in maybe a matter of hours, though the duration of your travel time would depend on how many Gs you can sustain.

 

[Archabacteria]

If you want to go at FTL speeds to the Moon, you'd be wanting to go extremely fast. At the speed of light travel time to the moon is on the order of seconds. Any powerful enough drive (and if you're building wormholes and travelling through hyperspace, you should have extremely powerful drives) should get you to the Moon in maybe a matter of hours, though the duration of your travel time would depend on how many Gs you can sustain.

Hmm, probably right. Perhaps wormholes could link important worlds so that ships with less resources can go through that instead of spending extra time in hyperspace.

As for G's, the species that has this technology evolved on a higher gravity world- the mass of the planet is around 2.9861e+25kg, and the circumference is around 75,000km (slightly less at the poles, of course). ((In fact, in the map I made with the aforementioned program, it was exactly 75,000km, but I would suppose that that is kind of difficult to have, a nice, round number on such uncertain things as an oblate spheroid.)) It also has a mean density similar to that of Earth (or at least I think so, feel free to prove me wrong, I don't know anything past Algebra II- and I'm still learning that one), all of which give me no idea of the G a creature on the planet would have to withstand to survive.

However, I'm also thinking that they have titanium in their bones in about the same places we use calcium. I don't even know if titanium could ever make an organic molecule necessary for the 'spongy' structure that helps keep the bones flexible enough to not be brittle.

 

[jedidia]

(or at least I think so, feel free to prove me wrong, I don't know anything past Algebra II- and I'm still learning that one)

No high math needed to calculate what you need there.

surface gravity = GM/r^2, where G is the gravitational constant = (about) 6.673e-11, M the mass in kg, in your case 2.9861e25, and r is the circumference / Pi, that's basic geometry.

So we end up with (6.673e-11 * 2.9861e25) / ((75e6 (meters) / Pi)^2) = 3.496 gravities. I didn't even get to Algebra II, by the way, my school education finished at basic algebra and trigonometry. This stuff is really basic, all you have to do is look up the equations and put your numbers in.

Now, considering that a world with that surface gravity has a potentialy very dense atmosphere, you could make your high-G dwellers rely on buoyancy (how is that spelled again?) rather than exotic bone structures. If there's anything you WON'T find on a world with that surface gravity it's heavy organisms. Sturdy yes, but probably pretty small and lightweight. Yes, it's a bit counterintuitive, but here's the deal: I can drop my cat from my balcony without any danger whatsoever, but when an elefant misteps and falls over while running there's a very good chance of fatal internal injury because he's smashing himself to death with his own weight. Ergo, cats would fare way better in a high-g environment than an elephant.

 

[T.Neo]

However, I'm also thinking that they have titanium in their bones in about the same places we use calcium. I don't even know if titanium could ever make an organic molecule necessary for the 'spongy' structure that helps keep the bones flexible enough to not be brittle.

I'm not sure about titanium, there are several reasons why it wouldn't be as biologically suitable as calcium hydroxipatite, and a titanium mineral might not even be that much stronger.

If my potentially highly incorrect assumption is... correct, the square-cube law (also explained in J.B.S. Haldane's essay, On Being The Right Size) will affect the size and shape of organisms, and as gravity increases, an organism with a constant mass would decrease in size roughly by the cube root of the weight increase. By this logic a 1.5 meter tall 80 kilogram organism would be around a meter tall and would weigh around 280 kg.

Essentially it has to do with supporting oneself under the force of gravity. Other size-related things such as eye structures, and the structures within the digestive tract and respiritory system don't change. 80 kilograms of mass is still 80 kilograms of biomass; it's just that here, that 80 kilograms weighs 280 kilograms.

The mass doesn't decrease with the size increase, because that volume is effectively just being repositioned to support the animal better. In short, organisms will be stockier and generally smaller, but they won't be tiny or pancake-shaped.

Essentially, compare the shape of an 80 kilogram organism on Earth with a 280 kilogram organism. 280 kilogram organisms exist, but they're more limited than 80 kilogram organisms. Same goes for jedidia's falling cat example; a 280 kilogram organism can survive a short fall, but a shorter fall than an 80 kilogram organism. It isn't like they'll be terrified of heights; they'll just be more weary of them.

Other things scale differently; for example, if the tree analogues there work anything like the trees here do, they'll need to pump fluids up from their roots using transpiration, which limits their size. I assumed that this would result in a linear height decrease.

Atmospheric buyoncy probably won't help much (you'd need huge gasbags and they'd just be fragile and impractical), but another thing a thick atmosphere helps with, is flight. A thick atmosphere can make flight much easier, and could even make flight easier than it is on Earth, despite the higher gravity.

So these guys will naturally be able to withstand higher G accelerations than we can (they can accelerate far faster than we can and walk around the cabin in perfect comfort, whereas we would have to be relegated at least to soft foam acceleration couches).

Of course, higher acceleration means you need a sturdier structure. And you need a more powerful engine. Which means you need to deal with more waste heat. Which means you need larger waste heat mitigation systems. Which means you need more mass. Which means you need a sturdier structure. Which means you need more propellant. Which means you have more mass overall and you need a bigger engine to accelerate it...

It isn't impossible, but it does become an evil vicious cycle. It would be very diffiicult to achieve.

Of course, handwave a little and invent a perfect mirror, along with maybe a matter-to-energy conversion drive, and you've now got a spacecraft that can have a thrust power in the petawatts and not have to worry about waste heat, can achieve high accelerations, has an insane specific impulse, can be extremely rugged, and use anything easily deliverable to the engine for propellant.

In short, pretty much the ultimate fantasy of any sci-fi fanboy.

 

[jedidia]

In short, pretty much the ultimate fantasy of any sci-fi fanboy.

Given that from his description they are a very advanced civilization planting artificial wormholes all over the galaxy, Such a handwave for their propulsion tech should be forgivable. Just don't get into the technical details, lest you end up with Star Trek technobabble. As long as the race is sufficiently advanced and doesn't share its technology nor any details of it, you can fall back to "we sure would like to know how they do it, but they never tell..."

Atmospheric buyoncy probably won't help much (you'd need huge gasbags and they'd just be fragile and impractical)

A planet with 3.5 g surface gravity could have a very dense atmosphere without handwaving, which would make the arangement not all too impractical when compared to others. It still would beg the question of how they managed to get into Orbit on a world with 3.5 g and 10 bar atmo density, though...

I'm not saying it *has* to be, but for that surface gravity it might be a good solution.

 

[Archabacteria]

A planet with 3.5 g surface gravity could have a very dense atmosphere without handwaving, which would make the arangement not all too impractical when compared to others. It still would beg the question of how they managed to get into Orbit on a world with 3.5 g and 10 bar atmo density, though...

I'm not saying it *has* to be, but for that surface gravity it might be a good solution.

This species won't, but I can see there being gas bag creatures around. Perhaps the kind that feed on flying photoplankton and other such airborne things.

As for the rest of the advice as to the species, I've taken this into consideration and figure it wouldn't be terrible to have them be shorter. Five feet (152.4cm) sound around right? The tree-climbing subspecies can be even smaller, of course.

And with that much atmosphere, I would guess that they would have a hard time adapting to an Earth atmosphere even at sea level. Perhaps some genetic modification or cybernetics would explain it. But I'm sure their skin wouldn't rip open like a certain species from Mass Effect, right?

And I was pretty much going to go with 'I have no clue, they haven't told anyone' for the technology. Including the part where it gets so advanced that people are flinging fireballs. Something about turning air into hydrogen and mixing it with the right ratio of air in a sphere.

 

[T.Neo]

The only difference they'll have is probably oxygen availability. Dealing with that is simple; just use an oxygen mask.

They shouldn't rip open, after all, sea creatures from about 10 meters under the ocean don't rip open when they're brought to the surface. Rapid decompression would be a problem for them though; they'd have to decompress slowly for the same reason divers have to ascend to the surface slowly.

I hope for evolution's sake they don't look like humans... :shifty:

 

[fsci123]

Well any planet with 3.5 G would probably have a mass of 6-9 earth mass which places it on the border of a gas giant... So it may have an atmosphere of supercritical fluid which is pretty interesting... It could e like an ocean of air except it would be a great notice

 

[Archabacteria]

Nope, it's exactly 5 earth masses. Look down a few posts for how we got 3.5G.

And no, they don't look like humans. I can't go into details very much, but they fit in the classification of mammals but have some other interesting features.. Like scales. There is skin beneath that which has hair, so don't stare too hard at that sentence. While I can try to make things as alien as possible, there's only so much I can do when I want a sentient species on two legs. Eventually, it will resemble something, no matter what you change.

 

[jedidia]

Mind you, you don't *have* to have that dense an atmosphere, I just thought it might be a better solution than titanium alloy as bones...

Something about turning air into hydrogen and mixing it with the right ratio of air in a sphere.

Not much hydrogen in (our) air, except for water vapour, and water brings the right ratio of oxygen for a hydrogen explosion with it. Maybe something they can only do at a certain humidity, that could put an interesting restraint on their super-powers.

 

[T.Neo]

A planet with 3.5 g surface gravity could have a very dense atmosphere without handwaving, which would make the arangement not all too impractical when compared to others. It still would beg the question of how they managed to get into Orbit on a world with 3.5 g and 10 bar atmo density, though...

You probably won't get that much help from buyouncy with 10 bars of atmospheric pressure though. Even relatively small gasbags would probably be far too impractical.

Fortunately the point of my long, rambly and potentially utterly wrong post about square-cube law is that you shouldn't need such extreme features as gasbags or titanium bones to stay alive...

But I generally don't see a problem until you get into the aburdly high G levels, where an 80 kilogram organism weighs 800 kilograms...