Plausible space velocities for stories.

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One of the stories here got me curious about the "Star Wars" series, for purely technical reasons. :) So, I began to watch the entire series again from I-VI. In Epi IV, Han Solo mentioned that his ship would do 1.5 light speed. Hmmmm that is just plodding along and is really not much good for space travel. In Lili's present story, she mentioned that the drive she is peddling is capable of 100,000 times light speed; something just barely useful considering the scale of the Universe, or even our own Galaxy.

Isn't it interesting how in just the space of slightly over 30 years, our sense of scale has changed so much.

Gwendolyn

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Well the problem with Han

Well the problem with Han Solos comment was that the speed he told is way too slow. You'd still need years to traverse between star systems.

In science fiction literature there are two movements: Faster than light travel is impossible, or faster than light travel is possible and the speed or the function is a matter of the plot.

OR...

Space is folded or compacted in which case the real velocity and the apparent velocity would differ. Even moving at a fraction of lightspeed in 'real' space is not going to be possible. Not because of relativistic effects (but yes, them too) but because space is decidedly not empty. It may be a 'good' vacuum but it is far from perfect and those few molecules will impact as or like radiation. There will be no 'real' space interstellar drives except on multi-generational (real slow) ships.

So there is simply no plausible space velocity for interstellar drives. It is the wrong question.

Any 'FTL' drive would also be a time machine - math requires it. So maybe someone could build a TARDIS one day, but that has another downside. Once you separate from (leave) your origin you are completely distinct from that universe. It is beyond and event horizon. There simply could not be any navigation and 're-entry' would find you in a new universe even if you could not tell the difference.

Regretfully, interstellar distances really are 'god's own quarantine regulations'.

The only feasible (possible?) drive is some form of space compaction that does not require an even horizon and no mechanism for this that I am aware of has ever been postulated .

Yuck! That sounds horribly male...

Why would being technical be male?

That doesn't follow, especially considering the fact that since limits on enrollment have very nearly vanished, women are rapidly taking up the technical fields more than men. Women are more detail-oriented in general than men are. The way the female mind works lends itself to multitasking necessary for technical tasks than does the male mind. This is part of why male geeks, nerds, dorks, etc. have always been picked on by the jockish (jock-itch?) types, as they seemed to be boys with girlish interest in techie stuff. At least, that's the perceptions that I've noticed.

Secondly... when Han Solo mentions that the Millennium Falcon can do, "... point-five above c," that was a lack of George Lucas' knowledge of anything to do with space travel and has been passed off since that the Falcon was able to do 1.05c without engaging the Hyperdrive (which is a mechanism that allows the ship pass through non-relativistic space in a form of space compaction that does not require an event horizon -- postulated by Gene Roddenberry, Isaac Asimov, Robert Heinlein, John Michael Straczynski, Ben Bova, and many other science fiction writers {including George Lucas after he actually did research between A New Hope and The Empire Strikes Back}). You see, I am one of those geekish girls, and people knowing I'm a girl instead of thinking I'm a boy doesn't change what I know. Heh. In the Star Wars universe, as soon as the geeky fans pointed out exactly what Gwen noticed to Mr. Lucas, he started to research and it has since been defined that, "...point x..." above or below c in the Star Wars universe is meant as referring to the last one-tenth of c above or below. So Solo's comment was saying the Millennium Falcon could do half of one-tenth above lightspeed without engaging Hyperdrive.

Umm...

It was the overly "authoritative" (read arrogant) reply that I meant as too masculine not the content itself. The way it was expressed not the information. Apologies.

Well another possibility

Well another possibility might be to have a bubble of spacetime where the space ship flies in. Within that bubble time flows faster, the ship ages faster than the universe around it. That means the ship might fly with speeds way lower than lightspeed, but since the bubble ages faster it might move with higher speeds relative to the universe around.

I don't know if this might work, it is just an idea of mine.

Yuck! That sounds horribly male...

Why? That sounds horribly geeky. It is a tragic cliche, that you have to be male to be a geek. Leads to a much to low influx of female participants in geekyness ^^

Hi Gwen.


Yes, your quite right Gwen even 100,000 times the speed of light is pretty useless when you think that the event horizon is deemed to be thousands of LIGHT YEARS 'accross'.

I cunningly circumvented the whole question of 'Velocity' by actually 'warping' the pertinent space around Cold Albatross to enable her to 'cross' finite distances in an instant or move an infinite distance in a finite time. Whichever way you describe this 'space warp' it enables the traveller to get to places within an instant if you wish or more manageably within a very short time thus giving the space traveller a sense of 'going' and yet not experiencing the real action of her craft. The concept of 'speed' or 'velocity' becomes irrelevant.

As you correctly point out, any correlation of travel in terms of 'distance per unit of time' instantly becomes implausible when on studies the sheer size of the universe and then try to 'pick a velocity' to suite that size.

The universe is deemed by most scientists to be 15,000,000,000 years old, so, bearing in mind at the event horizon the expansion is deemed to be accelerating close to the speed of light, then that means the universe at or even past the event horizon is close to 30,000,000,000 light years diameter. At 100,000 times the speed of light it would still take 300 years to cross, not a very practicable time scale for humans and hopelessly inadequate for external interaction with others 'left behind' on the 'home world'. And as for 'intergalactic communication', this speed is still somewhat impractical.

And let us not forget that 'dark matter' is deemed by some to be pushing the 'envelope' of the event horizon bubble outwards at an ever increasing rate as the universe continues to expand since the big bang.

As I see it, warping space is the only way to go for it gives the Sci-Fi author 'space-time plausibility'.

Thanks Gwen.

Hugs.

XZXX

Beverly.

Growing old disgracefully.

bev_1.jpg

100,000 times c...

Puddintane's picture

...is very fast indeed. It makes crossing our Galaxy roughly equivalent to the ‘discoveries’ of the Age of Exploration, a year from one edge of the Galaxy to the other, and much less than that to anywhere closer, three months to the centre of the Galaxy. Considering that most of the Earth's great empires were built firmly within the bounds of a very similar time regime, this makes the Star Trek and Star Wars scenarios very plausible. Too much speed available to an empire degenerates very quickly into a single empire, as the British Empire came close to doing, and the American Empire would have, given more will and less greed.

Cheers,

Puddin'

A tender heart is an asset to an editor: it helps us be ruthless in a tactful way.
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-

Cheers,

Puddin'

A tender heart is an asset to an editor: it helps us be ruthless in a tactful way.
--- The Chicago Manual of Style

Being a fan of SciFi, I've

Being a fan of SciFi, I've often thought of this and realized just how slow Star Trek ships were. The Milky Way is about 100,000 light years in diameter. A speed of 100,000C would easily allow for the exploration of the galaxy. The original Star Trek ships only went about 1000C at max, The Next Generation and beyond could go faster, but only for a short time.

To explore the near parts of the Universe you would need probably 100 times that speed. It is 2.5 million light years to the Andromeda Galaxy. The nearest other galaxy is actually closer than the other side of the Milky Way.

To explore the whole universe? That may not be possible, it is unknown as to how big it is, and some think that it is infinite.

Space is really really big!

I did always wonder about that quote "She'll make point five past lightspeed." Point 5 whats past lightspeed? 1.5 lightspeed is very slow.

In the RPG

In the role playing game (yes, I know) there's a "standard" speed for shipping lanes, with a ship rated to the number of times slower than "standard" speed. Most military ships are about a 1, some slower cargo ships get to a 3. So by saying he does .5, he's really saying it goes twice as fast as an Imperial cruiser.

Of course it's rubbish invented after the fact to make sense of Han's comment, but that doesn't mean we can't have some fun with it.

The Kessel Run in 12 parsecs

Remember, Han Solo also claimed, in episode IV, that the Millennium Falcon made the Kessel Run in 12 parsecs, while describing how fast she was. Since a parsec is a unit of distance, and not time, what we can conclude is that Han Solo pointed the ship where he wanted to go, and did some fancy flying, but had no clue how fast she really went.

How fast?

Whenever I've thought about travelling the galaxy I've done it this way:

Firstly, ignore that old Einstein rubbish. If your story is going to work at all you have to ignore relativity - unless your story depends on the effects for dramatic purposes.

Then look at the closest star, Proxima Centauri. That's about 4 (ish) light years away, so travelling at the speed of light it will still take you four years to get there. At that rate, it'll take someone the bulk of their life to travel anywhere that's even close to Sol, so we need to think about upping the speed somewhat.

4 x speed of light = get there in a year. A year? The closest star? Still way too long.

365 x speed of light = get there in four days. Okay for Proxima Centauri but in practice the galaxy is so big it's still too slow.

365 x 4 = 1460 x speed of light = get there in one day. Now we're talking! But Proxima is the closest star; going anywhere else is going to take much longer. It will be like travel around earth before airplanes at the very least. At those speeds it's still going to take you upwards of twenty years to get from one side of the galaxy to the other!

So, it can be done, but the numbers involved are huge (in fact I would say that they are astronomical ;) and that's why most SF authors plump for some kind of warp/hyperspace/wormhole kind of device to avoid the need to spend years of their characters life in transit.

Penny

Most, but not nearly all

If by, "... most SF authors..." you mean more than half, yes, I agree 100% with you! But there is a significant amount that also use cryogenic/coldsleep/freezietime solution: the Alien series, Lost in Space, Red Dwarf, and Avatar for example -- and even those with Hyperdrive devices tend to mention that Cryogenics were used prior to the discovery of Jumpgate or Hyperdrive technology.

food for thought

bobbie-c's picture

If I remember correctly, Han Solo said the Falcon can make it past point five the speed of light. That statement was vague enough that people can assume the Falcon can fly at 1.5 times the speed of light, or that the 0.5 refers to some other unit of measure. Many Star Wars fans say that the 0.5 is actually a classification of spacecraft, making the Falcon of the same class as emperial destroyers, in terms of speed, that is.

(btw, about the Kessel Run thing, my friend, who is a rabid StarWars fan, says that is more a reflection on the capabilities of the Navicomputer of the Falcon, that the Falcon is able to find such a short path through this asteroid-ridden part of space that ships usually have to navigate around. That to make the shortest Kessel Run is actually a mark of distinction for pirates. Actually all this explanation was just a way for the fans to rescue George Lucas from a mistake he made in his script when he used parsecs in place of light years...)

As for Star Trek, I don't really completely understand how warp speed is computed, except that it is a cube of some formula, and that Warp 1 is the speed of light, warp 2 is 8X the speed of light, and warp 3 is 28X the speed of light. Also, that in Captain Picard's time, the Voyager class of starships (which was experimental, to begin with) wad the fastest in the fleet, capable of warp 9.9, or faster than 21,000 times the speed of light (but only in limited hops). Also, per the fans, and the series Star Trek Voyager, this largely exponential formula for warp speed breaks dowm at warp 10, due to the Transwarp Barrier, or the Eugene Limit (named after Gene Roddenberry). Actually, it's because, if the formula is used for computing warp 10 and above, the speed surpasses 100,000 times the speed of light, and, given the Milky way is only 100,000 light years across, galactic travel would become humdrum, and that the drama of space epics would substantially be reduced.

If someone were to ask me, I guess, storywise, spaceship speeds of around 12 times to around 20,000 times the speed of light would be just right, because one can travel from Earth to Alpha Centaury in about a month at 12x the speed of light, or about a month to cross the galactic arm to which the Earth belongs, if she travels at 24,000X the speed of light. That's just fast enough (and slow enough) for some fine space drama to ensue.

As to the technology to allow this, well, I guess it's up to the writer's imagination. I mean, if people are able to suspend reality enough to find the TARDIS, the warp drive, or some mineral-derived liquid called Tylium will allow space travel all right, then sky's the limit for technology. Hey, why you can even claim it comes from the Omega 13 or something...

That's just an opinion, of course.

- Bobbie-the-Scifi-Geek

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Star Trek speeds

In Kirk and Spock days, Warp Speed was based on a cube times the speed of light. Warp 3 was 27 times the speed of light.

In Picard and Riker days, Warp Speed was based on a 5th power times the speed of light. Warp 3 was 243 times the speed of light.

The reason for the change was that between times, the people behind Star Trek realized how HUGE the friggin galaxy actually was.

Nice analysis...

MOST Science Fiction authors have to address the speed issue. They do it in many ways. Some invent special "engines" others incorporate other mechanisms so they can travel between point A & B without traversing the distance between them. Some authors have used light as a HARD barrier - and done the generation ship thing (or variations)... Some have "ignored" the speed issue, and just "assumed" it's solved in the future.

IMO - the type of story should drive what kind of "technology" you need to get around it. If you need things to take a few days between star systems, that gives you one speed. If you need to be able to traverse between arms of the galaxy, then you've another speed.

MOST of the time, I pick an "era" in the Earth's history - and pick the transportation times involved there. For example, if you picked 1900 - and had your "continents" in the solar system... You'd want to arrange your space drive to require about a week or two to travel between planets when they are close - and a month, when they're far away and no need for FTL (faster than light) travel. On the other hand, if you were to use star systems and the same time scale - you'd need to exceed light to get the same travel (if you have your people awake.

Another big factor is expense of travel between stars/etc. and how much "cargo" could be carried. Do you systems all need to be "self Sufficient" / what kind of trade is reasonable/possible. Just look at the history of North America - and European Colonization - what kind of things could be carried between the old world and the new? etc. If you have the same kind of travel times between your "systems" you might have similar transportation issues as far as trade... That, or you need to invent a way for transports (ships) to be able to carry sufficient "bulk" to to make it worth while. That, or you go that trade's just with luxory items.

Something else that can be considered is EXPENSIVE VERY HIGH SPEED travel vs. much slower (but useful) lower cost travel.

So many options and so many ways to handle things. The key, I think, (as has been said/alluded to by others) is that whatever you choose, it should be internally consistent and SOUND at least plausible... To support the readers suspension of disbelief.

Anne

Plausible space velocities for stories.

In Star Trek, there is the classic warp drive as well as the much faster transwarp drive. Then there is time travel and travel between dimensions.But if you are "Q" you just snap your fingers.

    Stanman
May Your Light Forever Shine
    Stanman
May Your Light Forever Shine

Don't Get Hung Up On FTL Multiples

joannebarbarella's picture

Fictionally, multiples of the speed of light have varied from one to many thousands. Actually, if a vehicle travels at one light, theoretically no time passes on board, so that is quite fast enough to travel the galaxy for those on board. It isn't fast enough for those observing from a planet.

If you travel faster you arrive before you leave.

Most modern SF writers use "wormholes" to traverse the universe. In a wormhole there is no speed, just instantaneous transit from point A to point B, the only problem being "where the f*** is point B?"

Joanne

Hmph

Generally said authors also peg wormholes as a natural side effect of a massive object's existance, to justify the wormholes connecting the star systems.

Faraway


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Space travel mumbo jumbo

Here is another wrinkle to space travel, and one that may make it practical. Please keep in mind that this is from a mind that just found out that there are presently 16 dimensions postulated by the Math Guys. Maybe what can happen is to pop yourself up to the 12th dimension to travel?

David Weber mentioned traveling in the E and F bands in one of his books. What's that mean?

Hmmmm

Gwendolyn

Hyperspace

It is all explained in the David Weber books, actually, if you look hard enough. Strangely, I'm currently re-reading my way through the whole set so far, now I've managed to find a decent chronology to fit in all the short stories in their proper slots.

But I digress... He uses the concept of 'hyperspace' and I think this means a sort of dimensional shift such that if you go from A to B in hyperspace it's a shorter distance than in normal space. Hyperspace is divided into bands, each identified by a greek letter. The higher up the greek alphabet you go, the more twisted space becomes, the shorter the distance but the more difficult it is to navigate there. Going from one band to the next requires more energy and better compensators, which means that in practice only military types and dispatch boats can use those.

I think his universe got so involved that he's ended up writing whole papers on how it all works. Some of the later books have detail descriptions of how the warships and weapons are built, even. personally, I don't need that kind of detail, I prefer to just assume that it all works, assuming some kind of internal consistency of course.

From the point of view of how things work, I much prefer the universe of Lieutenant Leary by David Drake. Spacecraft land and take off from water and actually have sails, travelling by navigating between bubble universes. Much more fun!

Penny

Mr. Weber is famous for his

Mr. Weber is famous for his "info dumps". Large chunks of text that just explain either technology, or politics or something else. They can be somewhat challenging to read, and I generally just kind of skim over them.

Many authors use the term "hyperspace" and almost all of them have different meanings for it. Some authors even use it to mean different things in different books they write.