Can you "condense" a magnetic field and use a precision magnetic "beam" for space travel?

[caesartherome]

Hey all,

So I've been writing a hard science fiction novel and need real answers from someone who understands the fields better than I ( I have no formal education outside basic high school classes in physics)
The problem I have is I'm not a fan of faster than light travel but I need a way for the explorers to travel great distances quickly.
My idea is this: A precision magnetic field, or simply a "beam" that is pointed at a corresponding station and the resulting magnetic attraction pulls the craft towards it.
I have no idea if that sort of thing is possible.
So I would like to know
1) How fast is magnetic attraction for extremely powerful magnets? And would those speeds offer the explorers the ability to travel great distances in a reasonable time frame?

2) Is a "precision magnetic beam" even theoretically possible?

3) What sort of calculations can I use to make the technology seem realistic?

4) If a system like this existed, would it affect any planetary magnetic fields?

5) A zero g environment means the system would only need to ping it's target station to retain it's speed, which removes the necessity for vast amounts of combustible fuel, but how could they slow down effectively without hitting the planet or the station?

I apologize if I put this in the wrong section, again I'd really like some input on this from people who understand it better than I.

Any help is Aprreciated.

Thanks again.

-Theron.

 

[TESL@]

Here is what I bumped into earlier, something very similar to what you describe:

http://arxiv.org/pdf/1304.6300v4.pdf
http://www.technologyreview.com/view/514201/physicists-build-worlds-first-magnetic-hose-for-transmitting-magnetic-fields/

edit: Assuming you are asking the speed you can acquire using magnetic fields in (1), you can calculate the force depending on the field strength gradient, then use linear momentum change to find final speed after a given t.

 

[PWiz]

Usually when authors want to make their characters jump distances (light years, actually), they use wormholes. The problem with regular travel (i.e. actually moving through space from one spot to another, regardless of the method of propulsion) is that the traveler ages considerably less than those at the destination/origin. In extreme cases, the other individuals die of old age by the time the traveler completes the journey (with him/her aging just a few years). Does this matter in your story? What distances are we talking about over here? Do you plan on making your characters travel very close to the speed of light?

 

[caesartherome]

I'd like to keep everybody the same age if possible and try to stick to realistic possibility as much as possible.

I'm leaning towards creating a solar system that's recently been discovered. Some where in the range of 5-15 light years.
The events take place after the moon and Mars are colonized so mankind is familiar with the local solar system.

I'd like the explorers to travel as close as possible, at whatever speed magnetic attraction occurs, so I'm limited by that technology, I'll have to warp the story and setting around that.

 

[PWiz]

Magnetic fields extending over 15 light years trying to accelerate a spaceship to near-light speeds does not seem like a very good idea to me. If you want to be realistic, IMO you should just allow mankind to discover how to manufacture very small quantities of exotic matter to make wormholes. You'll then overcome the aging issue (and the need for insanely strong mangetic fields).

 

[phinds]

Changes in magnetic fields propagate at c, but are PHENOMENALLY weak at any kind of distance. Use for space travel is a total non-starter.

 

[Vanadium 50]

1) How fast is magnetic attraction for extremely powerful magnets? And would those speeds offer the explorers the ability to travel great distances in a reasonable time frame?

Speed of light. No.

2) Is a "precision magnetic beam" even theoretically possible?

No.

That pretty much removes the need to answer the remaining questions.

 

[DaveC426913]

Concur with above. I think magnetism falls off as the cube of the distance, so vanishingly small after a short distance.
Also, it is unilateral in its targets, which means before a spaceship would even feel it, you'd be pulling buildings out of the ground.
And finally, there's no way to direct it. The closest you can is to sort of shield something from it by enclosing a target in a cage of soft iron, which will route the field lines around the target.

 

[Ryan_m_b]

In the manner you describe no. Something along similar lines is beamed propulsion, there are concepts that involve firing charged particle beams at a spacecraft which it uses to accelerate via a magnetic sail:
http://en.m.wikipedia.org/wiki/Magnetic_sail

Note that without some form of FTL your characters will not be getting around the Galaxy in a hurry.

 

[Vanadium 50]

Suppose we had an iron spaceship, and stuck a magnet in front of it attached to a stick...

<evil grin>

 

[caesartherome]

Dang, I figured I could at least get a bit farther than regular rocket fuel.

Oh well, I'll think of something !

Thanks for your answers I appreciate it!

 

[caesartherome]

I was hoping it'd be at least possible because "mag-jump" sounds really cool to me!

 

[Ryan_m_b]

What's your setting like? Perhaps we can suggest a suitable fictional form of transport that would be based on realistic science but speculative enough to fit in your story.

 

[caesartherome]

The setting is the first manned mission to study life on an exo planet named Athena which orbits a super giant and has a singular tidal locked moon that has life as well, but only around the areas where it's not to hot or cold. Sol has been respectively colonized with the general Mars colonies and moon bases etc and Athena was originally placed about 5 light years from Earth ( it's a completely fabricated solar system of course).

My original plan, if this was possible, was to make a man made metal that allowed pilots to manipulate the magnetic field.
So relatively close as far as light years are concerned but they apparently won't be getting very far at all ;)

I'd like to shy away from hyper drives, light drives or the "graviton" technology. I really don't want it to sound like pseudoscience but I'd also like to stretch the rules as much as possible.

The propulsion system is only there to describe the trip in a realistic way, the main idea of the book is the biology and geology of Athena and Luna B.

I've tried the "photon drive thing" and the only way I figured that could make sense is artificial man made particles that give photons the ability to act like they have mass without actually having them, in other words space magic.

So basically no space magic haha.

 

[Ryan_m_b]

Not sure what you mean by needing photons to act like they have mass. A light sail can impart momentum, though for any reasonable acceleration you're going to need a laser as the light source powered from the solar system. Did you check out the beamed propulsion link I posted above? It wouldn't be too handwavey given the subject matter to propose really mature magnetic sail technology. Essentially the spacecraft projects a really strong magnetic field around itself, back in the solar system a powerful array of particle beam generators fire charged particles at the craft. As the particles hit the field they impart momentum boosting it up.

You could propose something like that for speeding up to a cruise speed and perhaps multi-stage nuclear/fusion/antimatter propulsion for slowing down. Whilst technically it might require prohibitory amounts of fuel and power this is science fiction. Most readers will give these sorts of things a pass.

 

[caesartherome]

Well I did have a system of gates that stayed in position in open space that acted like "train tracks" that didn't exactly send the magnetic field the entire distance. Instead it'd ping the "radiostation" as I call them and the ships traveled through these and allowed the ship to maintain the magnetic attraction for greater and more precise distances than a realistic magnetic has.

 

[PWiz]

Well I did have a system of gates that stayed in position in open space that acted like "train tracks" that didn't exactly send the magnetic field the entire distance. Instead it'd ping the "radiostation" as I call them and the ships traveled through these and allowed the ship to maintain the magnetic attraction for greater and more precise distances than a realistic magnetic has.

So you had gates at regular intervals covering a distance of 15 light years?? Wait, is this like a well-established 'galactic motorway' of some sort in your story? I mean do people in your story regularly use it for coming and going?

 

[caesartherome]

Yes and no, the original discovery was an accident. They were essentially just probing open space and found the system.
As far as localized travel yes, they use them for trade routes to the colonies and random mega space stations that dot the localized system and open space.
I guess the best way to describe it is like when Americans first branched out to explore the west and had small homesteads and pioneers in the far reaches of the land. They sent the gates pre conctructed into space whenever they had the chance so some gates haven't even been traveled thru or even locked into the system yet.

I've got the destination and the story solid from there, it's just the beginning and the realism behind the trip I'm having trouble with.

I'm thinking about scrapping the distance completely and playing off of the "nemesis idea" of a second sun near ours.

 

[Ryan_m_b]

As far as localized travel yes, they use them for trade routes to the colonies and random mega space stations that dot the localized system and open space.

So you're imagining a scenario where strung out between planets are a line of magnetic gates that pull a ship in and throw them out the other side? That's unworkable for a few reasons;

1) There's no way to direct a magnetic field as a beam, a craft would have to come very close to such a gate.

2) Planets in a solar system aren't just sitting at rest to each other, they're all orbiting the sun at different speeds. Even if you managed to get a line of gates strung out perfectly between two planets within a very short amount of time they would be spread out into completely different places.

The closest feasible technology resembling this would be some sort of magnetic mass driver/rocket sled (scroll down on the last link). You could have some sort of megastructure in orbit of each planet that's a form of coil gun; accelerating a craft and shooting it out. The speeds achieved would be impressive but not ground breaking, a 1000km tube accelerating at 20gs would only impart 19kmps by the time the craft exited. Respectable but that's something rockets could achieve.

 

[DaveC426913]

This would work wonderfully as a retro-Vernesque or Wellsian story.

I just finished reading Stephen Baxter's The Time Ships - a sequel to Wells' The Time Machine - it picks up the very moment Wells' epic story leaves off. In it, he explains that the time machine was powered by Plattnerite, a mysterious glowing substance whose properties are never clearly explained. (It's the equivalent of the "magic potions" that so often drive Gilbert and Sullivan* stories. Doesn't matter how it works, only that it does.)

*did I get that right?

 

[Khashishi]

That sounds a lot like the common science fiction technology called a tractor beam. This is kind of subjective, but it sounds less unrealistic to me than wormholes. As far as magnetic fields go, it's hard to focus it in empty space. You can arrange your magnets in an array to preferentially direct in one direction (see Halbach array), but I don't think you can get anything resembling a beam.

 

[TESL@]

1) There's no way to direct a magnetic field as a beam, a craft would have to come very close to such a gate.

Please see the second post.

 

[Durakken]

I suggest reading through Heinlein as he has some wonderful concepts in his books regarding travel at these types of high speeds.
For example he intruduces the concept that it's not that you can't breach the FTL Barrier it's just that when you do you need to do it precisely or you'll end up somewhere you don't want to be. Extending that to a more "realistic" method of using this concept than a drive you could use a Jump Gate that accelerates the mass so quickly that it overcomes the infinite mass problem.

He also introduces the concept of null-space where time and distance is irrelevant much like in a wormhole which then gets parlayed into later works as realizing that if that is the case you can move in any parrallel axis dimension and results in time travel abilities and universe hopping ^.^

 

[Ryan_m_b]

Please see the second post.

Yes I've seen it and I stand by my statement, the OP is talking about projecting a magnetic field from A to B with no intervening infrastructure. The study you linked to, as I understand it, requires a long tube to be placed between A and B. Not the same.

Extending that to a more "realistic" method of using this concept than a drive you could use a Jump Gate that accelerates the mass so quickly that it overcomes the infinite mass problem.

That isn't realistic at all, it doesn't matter how fast you accelerate you can't propel an object with mass at the speed of light or faster.

 

[Durakken]

That isn't realistic at all, it doesn't matter how fast you accelerate you can't propel an object with mass at the speed of light or faster.

I said "more" realistic. Not realistic. I'm comparing to a ship that is carrying fuel on board.

 

[Ryan_m_b]

I said "more" realistic. Not realistic. I'm comparing to a ship that is carrying fuel on board.

I'm not sure what you mean, are you suggesting it's more realistic for a ship to be accelerated to FTL speeds by a canon than to do it by accelerating on its own? Because those are equally unrealistic. I think the OP wants something that is physically possible, even if it requires some speculative engineering. FTL doesn't come into it (though I suppose at the extreme end of this you could propose wormholes that are created then moved at STL speeds to the desired destination, AFAIK wormholes are technically not impossible).

 

[Dotini]

A visible filament of magnetism. Length is maybe twice the distance from Earth to Moon. The plasma and particles may amount to 100 billion kg. Once detached from the sun, the CME may travel up to 12.75 million kph on its journey to the planets. Hitch your space jalopy to this for a wild ride in the solar wind!

 

[Durakken]

I'm not sure what you mean, are you suggesting it's more realistic for a ship to be accelerated to FTL speeds by a canon than to do it by accelerating on its own? Because those are equally unrealistic. I think the OP wants something that is physically possible, even if it requires some speculative engineering. FTL doesn't come into it (though I suppose at the extreme end of this you could propose wormholes that are created then moved at STL speeds to the desired destination, AFAIK wormholes are technically not impossible).

It's more realistic in 1 aspect, that being that you don't have to carry infinite fuel, creating infinitely massive ships.
Also it is not completely outside the realm of possibility as there are credible hypothesi that propose something along the lines of light speed being somewhat of an artificial barrier caused by how we measure and matter we generally interact with, but isn't a true barrier. I'm not arguing the point, just pointing out that there degrees of "realistic".

The problem with wormholes imo is that they're useless in terms of fast expansion civilizations if you could get them to work and you don't save on time or energy as all the ways I've heard proposed to create a worm hole requires that you link the hole and then take one side to where you want it and while doing that that causes the sides to also move in their time distance which means that if you make a wormhole and then set it up so you can travel from Earth to 4 ly away you are still, first it's going to take however long it takes you to get out there to get it out there and then when you go through it you will take the exact amount of time to get there as you would otherwise. Then there is the whole maintaining it at all times which drains energy so you need to have an energy source and somewhere secure to set it up... Though the interesting point of this is the time difference and dealing with it... Let's say it takes 1000 years to travel that 4 light years. and 2000 to travel 8. What you end up with is...

Earth Date = 2000
A desitination Date = 3000
B destination Date = 4000

Even though this is true supposing that you use no other way to travel and communicate between these points and use Earth as the base hub it will appear as though they are happening at the same time. Although this could get weird if you set up redundant wormholes on the other planets which assuming a certain formation you could end up with 1 destination's wormhole to another is ahead or behind the chronological order of another... And I don't even want to think what would happen if you tried to take a wormhole through a wormhole.

Warp of some sort to me seems more realistic, stable, and doesn't cause time problems.

The other types of travel are Slip Stream and Hyper Speed. Slip Stream is like Hyper Speed, but relies more on the idea that there are pathways that allow for FTL speed, but outside of these pathways it doesn't work. Hyper Speed relies on the concept that you don't travel FTL but rather you travel through other dimensions which allows a journey that would require FTL to apparently occur while not actually breaching FTL. Probably the best way to think of this is if you were to imagine that you could only see the end beginning and ending points of a take off of a jet and the Earth was was flat in your reality but in the real reality it was still curved. This would make it appear that a jet could arrive at point B from point A quicker than a flatworlder would believe they could because the jet didn't travel through the points between point A and B in the flatworld, but rather some dimension above flatworld that is curved.

The only one of the 4 options for FTL that is somewhat silly is the Slipstream idea which is really just a conglomeration of the other 3 with weird restriction that could come about from the other 3 but doesn't seem likely.

If you're against FTL at all, then look up the word "Torch Ship" which is the idea Heinlein uses for much of his work Basically you fire your rockets/drive continuously. This is more or less all that there is for STL ships that can travel between stars. This comes with time dilation effects. However how one goes about powering this is interesting and this is used in a number of sci-fi universes though many ignoring the slow down part... the difference in how these works is as different as your basic rocketry to solar wind style ships. And of course the speed involved in these types of ships create quite a lag between interactions between civilizations and ships...on the other hand it is also probably the safest because the practicality of attacking them in interstellar space...which is explored in a heinlein book...though i don't remember which