Star Trek Nerd: What are force fields and why dont we have them?

[taylaron]

sorry about the fantasy factor here guys, but having a kind of barrier that can repel mass and be "mass less" without having any visible infrastructure would be quite valuable.

so the question is: What are force fields? (like the ones in star trek)
what would they compose of? and what keeps us from that technology?

i'm not talking about the effect that magnetic or electric fields have upon charged particles. simply the science of a fantasy (or is it?)
The effect of of repelling both protons, neutrons, and electrons.

*note
does any "theory of everything" in quantum physics (etc..) Predict such a phenomenon in the universe?

 

[D H]

so the question is: What are force fields? (like the ones in star trek)

The ones in Star Trek are of course works of fiction.

what would they compose of?

They most common construction material is http://uncyclopedia.org/wiki/Unobtainium" .

and what keeps us from that technology?

They're works of fiction.

 

[Hurkyl]

They most common construction material is http://uncyclopedia.org/wiki/Unobtainium" .

For further reference, see here.

 

[taylaron]

I suppose you can't question the science behind a fantasy...

 

[masudr]

Couldn't we have an electric vector field such as

[tex]
\vec{E}(x,y,z) = -E_0 \vec{j} e^{-y/\xi}
[/tex]

where [itex]E_0[/itex] is a large positive number, and [itex]\xi[/itex] indicates how "thick" the repulsive wall is.

This would work because all the negatively charged electrons on the outer shell of all normal objects on Earth will be greatly repelled if they approached the z=0 plane from the region y > 0.

Or have I made a glaring error somewhere? If it would work, maybe we could discuss possible methods of creating such a field (haven't thought about it properly, but can't think of any obvious candidates).

 

[HallsofIvy]

An electric field does not only affect the "outer shell". All "normal objects on earth" are electrically neutral and contain as many protons as electrons.

 

[russ_watters]

I suppose you can't question the science behind a fantasy...

Right. It's like asking why we don't have unicorns. They just don't exist and that's all there is to it.

 

[seycyrus]

I have seen some efforts that create a localized plasma around an object, which interacts with objects and energy crossing the plasma.

Sorta looked like a force field from the movies.

 

[jtbell]

They most common construction material is http://uncyclopedia.org/wiki/Unobtainium" .

I think it was Robert A. Heinlein who wrote a short story that went something like this:

Someone followed up on the observation that toilet paper and other sheetlike materials tend to tear everywhere except at their perforations (holes). He discovered that he could enhance the effect if he made the holes bigger. Continuing further, he removed all the substance and produced the strongest material known to man, which he dubbed "Nothing."

The best part was that he could take the removed raw substance, recycle it into new sheets, and use it to make more Nothing!

 

[peter0302]

We can at least say how a forcefield would NOT work. :)

A simple magnetic field doesn't work because macroscopic objects are not magnetically polarized.
An electric field wouldn't work for the same reason.

You certainly could make an invisible wall that would be very painful to step through, but it wouldn't physically block anything.

Yeah, so pretty much there's no known way of doing it. :)

 

[maverick_starstrider]

what if you were emitting obscene amounts of photons such that the radiation pressure would repel any incoming object (although you'd also instantly cook everyone around you to, but that's just an added bonus)

 

[peter0302]

It would be the momentum from the photons, and sure it would be possible to do. Do some calculations (E=hf) and tell me how many photons at, say, the infrared range (we want it to be invisible) we'd need to create enough energy to withstand a 100kg man coming at the forcefield at 10 mph. Then tell me how hot that would be.

Yeah, no.

 

[masudr]

An electric field does not only affect the "outer shell". All "normal objects on earth" are electrically neutral and contain as many protons as electrons.

What if the parameter [itex]\xi[/itex] in my description above was 5 orders of magnitude smaller than the Bohr radius? The electrical neutrality of atoms wouldn't matter as we'd push back the electrons before the protons could even feel the field.

 

[peter0302]

How would you make a field so narrow?

Also I'm not certain that works, since at any given moment the electrons have an equal probability of being on the wrong side of the atom, and therefore the protons would be attracted and it would all even out.

What you're talking about is artificially replicating what happens when solids touch. But that has more to do with the fact that the structure of the solid is stable and so resists being broken apart. There's a lot of QM involved. It's not simply the electrons from one block are repelling the electrons from the other block.

 

[Ivan Seeking]

There is ongoing work with "plasma windows" that somewhat resemble the fictional force fields imagined for windows and doors, on Star Trek.

Hershcovitch likens the plasma window to the “force field window” in the shuttle bay area of the Starship Enterprise in Star Trek. The “force field” separates atmospheric pressure in the Enterprise from the vacuum in outer space. In the plasma window, hot ionized gas particles are trapped by electric and magnetic fields. The particles, like any gas, exert pressure, which prevents air from rushing into the vacuum chamber housing the electron gun.

The plasma window is about 40 times as hot as the air at room temperature. This intense heat makes the ionized atoms and molecules move around faster and collide more often with air molecules, thus stopping most of them when they try to cross the plasma window. The electron beams can still pass through it unharmed, making it a viable non-vacuum electron-beam welding device.

The development of the original idea of the plasma window was made possible by a technology maturation grant from DOE’s Energy Research Division and Laboratory Technology Program. Also, Hershcovitch acknowledged the help of students participating in DOE’s Energy Research Undergraduate Laboratory Fellowships program in designing and piecing together the plasma window.

http://www.bnl.gov/bnlweb/pubaf/pr/2001/bnlpr121101b.htm

Also, I would imagine that if not now, eventually it might be possible to design materials that can be powered for added strength. Something like this might mimic some of the properties of the fictional "shields" on Star Trek.

 

[masudr]

How would you make a field so narrow?

I'm not discussing the practicality of the method (just yet), just investigating if the method would work or not.

Also I'm not certain that works, since at any given moment the electrons have an equal probability of being on the wrong side of the atom, and therefore the protons would be attracted and it would all even out.

That's quite correct, but if the electron is on the other side as it were (or, I should say, in all the systems of the ensemble of systems where the electron is on the other side), the field would still be weaker at the proton site than the field that is affecting the electrons nearest the "wall of field".

What you're talking about is artificially replicating what happens when solids touch. But that has more to do with the fact that the structure of the solid is stable and so resists being broken apart. There's a lot of QM involved. It's not simply the electrons from one block are repelling the electrons from the other block.

Oh yeah, I hadn't thought of it like that (I did a course on electrons in solids last year, and absolutely hated it *shudders*). I suppose then we cannot aim to replicate that exact behaviour due to what you say. Still I don't see any obvious objections to what I've proposed (apart from the practicality).

 

[johanw]

You would have to use gravity instead of electricity. This "reduces" the problem to create and structure artificial gravitation fields.

 

[peter0302]

Yeah I confess I don't understand materials science that well myself at the quantum mechanical level (i.e. the different types of lattice structures or what have you). All I know is enough to know that it's not just a simple coloumb force at work. :)

Gravity!? How would you propose to make gravity repulsive?

 

[taylaron]

what about the whole "white hole" concept? (compared to black holes...)
given this graviton actually shows up in the LHC; and we discover an anti-graviton; then mebe...

 

[OAQfirst]

If you're going to have an invisible force field, how will it stop a laser? That part never did look right in Star Trek.

 

[masudr]

You can't stop a laser unless you have something that is opaque to the frequency the laser is operating at.

 

[vociferous]

I think that there are several ways one could make a "force field".

Magnetic fields could work, but they would have to be ridiculously strong. If you have a strong enough magnetic field, it will magnetically polarize even non-conductive compounds. You may have seen the famous picture of a small frog being levitated by an extremely strong magnetic field.

http://www.phys.ufl.edu/courses/phy2049/spring08/images/FROG.MPG

Another possibility would be some kind of static electrical field, like that created by a Van de Graaff generator.

A third option, which is the one I believe the writers of the show take, would be to "warp" space, similar to how the warp drive is supposed to work. I think that this is also supposed to be the basis for the "cloaking field." The idea that space can be warped is not new, but other than gravitational fields, it is mostly speculation as to how it could be done.

 

[Charlie G]

I suppose if you had a strong enough magnetic filed the diamagnetism of most objects could repel and prevent them from getting beyond the field, but with a field that strong you might have hauge chunks of magnetic materials flying at whatever is generating it lol.