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So in many sci-fi franchises, there are these things called "grav-lifts" that supposedly cancel the pull of gravity of whatever they are placed on the bottom of.

So is this possible?

I understand that we don't have gravity manipulating devices, but in theory, would such a device be possible?

If not, is there a way to mimic this effect? And I don't mean hovercraft such as we have today with an air cushion. I mean actually being able to hover or lift-off with a similar device.


Edit: I seem to be getting a lot of elevator-related answers. I am not asking for levitation for the use of something like an elevator, I am asking it in the context of a hovering/flying vehicle

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    $\begingroup$ even if it was possible: going up would be like falling with your head first. extremely uncomfortable. $\endgroup$
    – ths
    Dec 7, 2020 at 23:58
  • $\begingroup$ @ths Not if it applied to all parts of your body equally. If we're making stuff up, why not? $\endgroup$ Dec 8, 2020 at 4:12
  • $\begingroup$ @AzorAhai-him- I think ths meant that if you were reversing gravity, it would feel like falling headfirst, rather than being lifted. $\endgroup$
    – jdunlop
    Dec 8, 2020 at 4:32
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    $\begingroup$ Or do you just mean a platform that's able to hover without any visible means of support, such that you could stand on top of it? That's quite a different thing from cancelling the pull of gravity, but it's certainly quite common in SF. It would help to clarify. $\endgroup$
    – N. Virgo
    Dec 8, 2020 at 4:48
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    $\begingroup$ @Nathaniel : in that case it wouldn't be any kind of "canceling the pull of gravity", it would just be a platform levitated probably by electromagnetic means. That's possible with today's technology. Probably they don't build them because of the costs involved, and safety concerns. But maglev trains exist, powerful electromagnets exist, so a platform raised by a series of circular electromagnets around it in a tube would be feasible. However, likely the fixed electromagnets would envelop it completely, so it would feel claustrophobic. And in case of a power failure you'd plummet down to death. $\endgroup$
    – vsz
    Dec 8, 2020 at 8:40

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Easy answer: No. Maybe.

More complicated answer...

If you ignore the word "grav" and look for any way to create levitation, it's hypothetically possible to create a magnetic field aligned to oppose the Earth's magnetic field to levitate an object. We see this the basic form of this effect already with superconductors. (Image courtesy the Royal Society of Chemistry.)

enter image description here

However, today we can only do this using another magnet as the base reference for the levitation. In other words, while the science has the potential to lead to "anti-gravity" (or simply "levitation"), we can not in any way do it today.

The problem, which is well explained here is that the Earth's magnetic field is so large and so spread out that it is both weak and uniform at any point on or above the Earth's surface. This means that you need an enormously intense magnetic field, even using superconductors, to levitate. And with technology today, that's flat out impossible simply because we have no way to lift the weight of the energy-providing device along with the Clarkean magnetic emitters.

And that's the core problem of why, knowing today's technology, the only valuable answer is "no Maybe." Thanks to various laws (like the really inconvenient laws of thermodynamics), we can't (perhaps, yet) see a way to produce that much power with a device that's so light that there's lifting capacity to add a burden.

But...

While the answer is that it's impossible today to do it, it isn't implausible such that it couldn't be used in a story. We have nuclear reactors that drive mighty aircraft carriers through the buoyant medium of salt water. The fact that we can build energy-creating systems that can propel objects much heavier than themselves implies that we just need to find the right combination of materials to do it for the sake of levitation.

Having said that...

The astute observer would quickly notice that I'm talking about levitation on a planet. Levitation on a space ship could be much, much simpler thanks to the need to bring the repulsive force with you. A plate on the floor that generates a strong magnetic field that the plate you stand on pushes against. It would be a neat trick to keep them aligned with any stability... but that's not beyond the possibilities of reason.

But the ability to walk around with a single plate and levitate anywhere on a planet or in space?

No. Maybe.


Edit: @ChrisH linked a great article that changes my "no" to "maybe."

Which, among other things, demonstrates the levitation of a live frog. Frog... Human... it's just a matter of scale, right?

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    $\begingroup$ " a magnetic field inverse to the Earth's magnetic field" that's surely a typo, JBH? You mean inverse to Earth's gravity, right? (the Earth's magnetic field is tiny and has nothing to do with anything about raising objects with magnets.) $\endgroup$
    – Fattie
    Dec 8, 2020 at 12:03
  • $\begingroup$ @Fattie, My answer is about magnetism, not gravity. It's poorly worded, but anti-gravity only comes (insofar as Humanity can understand) from negative mass. It would have been more accurate to say "a magnetic field aligned against the Earth's magnetic field." The only experiments levitating against the Earth's magnetic field (diamagnetics) have been successful only when the poles are reversed. However, you're not correct when you say "nothing to do...." It's possible, just not practical in any way, shape, or form. Please remember the context of the OP's question. $\endgroup$
    – JBH
    Dec 8, 2020 at 12:50
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    $\begingroup$ hi @JBH ! you may misunderstand me. The Earth's magnetic field is parallel to the surface of the Earth (and indeed, heading roughly towards the North pole). In your room, say, the (absolutely tiny) "Earth's magnetic field" will be directed from your sofa towards (say) your TV, horizontal, along the floor, parallel to the surface of the Earth. "inverse to the Earth's magnetic field" would just be from the TV to the sofa. Maglev trains, etc, or the photo in your answer, have (incredibly powerful) magnets which push UP towards the ceiling. $\endgroup$
    – Fattie
    Dec 8, 2020 at 12:57
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    $\begingroup$ hi @JBH , hmm, if you have basic training in Vectors and some physics, you'd see that it looks like you may have made a typo you just haven't noticed. Notice your sentence "possible to create a magnetic field inverse to the Earth's magnetic field to levitate an object" - such as in the blue photo. In the blue photo, the direction of force of the mag. field levitating the puck is pointing upwards; the direction of force of the Earth's mag. field in that photo is sideways (and it has no relation, at all, to the experiment.) You could ask on the Physics SE site for clarification. $\endgroup$
    – Fattie
    Dec 8, 2020 at 14:10
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    $\begingroup$ Diamagnetic levitation was used by Nobel winner Andre Geim, see first reference in link to levitate a live frog. Scaling up to humans (and enough height) is only probably impossible $\endgroup$
    – Chris H
    Dec 8, 2020 at 16:48
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In Newton formulation of gravity $F=G$${m_1 \cdot m_2}\over r^2$.

The general relativity formulation is a tad more complex, but it also states that a mass bends space time, and than bending causes what we see as gravity.

In both formulations the only way to make gravity a repulsive force would be to have a negative mass. A negative mass would be such that if you pushed it with your finger it would move toward your finger, not away from it.

Needless to say, at the moment we have nothing closer to that. So those devices are purely fictional.

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  • $\begingroup$ We do have negative energy, though, with the Casimir effect. $\endgroup$
    – nick012000
    Dec 8, 2020 at 11:40
  • $\begingroup$ @nick012000 Keep in mind L.Dutch is only talking about the force of gravity. Also keep in mind that the Casimir Effect is quantum and as yet has no application in the macro world. And if I understand it correctly, it doesn't express negative energy, that's just a mathematical convention to distinguish between attractive and repulsive force. Magnets don't have negative energy, either, but they do have attractive and repulsive forces that can be mathematically expressed as negative values. $\endgroup$
    – JBH
    Dec 8, 2020 at 13:01
  • $\begingroup$ That isn't quite correct. In general relativity you can create a small region with a repulsive force by taking a torus-shaped matter distribution and accelerate its spin around the circular torus axis (the way a smoke ring turns). There will be a "repulsive force" in that small region - though the object as a whole still attracts of course: aapt.scitation.org/doi/10.1119/1.1969340 $\endgroup$
    – S. Move
    Dec 8, 2020 at 14:16
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If They're Stationary, Probably

As has been pointed out by other responders, negating gravity is hard or impossible. Maglev, as suggested by @JBH, is an approach. But, assuming that your "grav lift" is an architectural feature like an elevator, then there is another potential approach:

Acoustic Levitation

So, recent developments in acoustic levitation use acoustic vortices to suspend objects larger than the wavelength of the sound. It can be ultrasonic, and therefore not (directly) dangerous to human hearing, but at the moment the best that can be managed is a 2cm polystyrene ball.

To levitate bigger, more massive things (humans, say) would require both better control over the vortices and a lot more acoustic power, but those are engineering challenges, rather than a matter of overcoming physical laws.

Now, this wouldn't be practical for something that was less elevator-like, you're not going to get a landspeeder from this, because the emitters have to surround the levitated object (at least in one plane), but if you absolutely, positively have to move a human (or similar masses) through the air from one place to another without putting them in a small mobile room, this is probably your best bet.

(It is, however, enormously less energy-efficient then lowering a small room attached to a cable, and then hoisting it back up again.)


I am including a link to a video demonstration under the fold, because the link might eventually go bad, but it is supremely cool to watch.

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  • $\begingroup$ "negating gravity is hard or impossible" quite a statement :) $\endgroup$
    – Fattie
    Dec 8, 2020 at 12:04
  • $\begingroup$ @Fattie Why do you think JD's statement to be unusual? Considering the expenditure of energy and effort just to put a satellite in orbit, he's absolutely correct. An illogical observation may suggest that a child's simple jump "negates gravity," but that's a false assumption because the child doesn't stay there. An airplane or a hot air balloon would be good examples of less expensive levitation, but those are outside the context of the OP's question. He/she wants anti-grav, not flight. $\endgroup$
    – JBH
    Dec 8, 2020 at 12:53
  • $\begingroup$ +1, I hadn't thought about acoustical levitation. Great idea! $\endgroup$
    – JBH
    Dec 8, 2020 at 12:53
  • $\begingroup$ @JBH - the "hard" part is funny. one can simply type "negating gravity is impossible" $\endgroup$
    – Fattie
    Dec 8, 2020 at 12:59
  • $\begingroup$ @Fattie Except that you'd be wrong. We negate gravity every time we launch an object beyond Earth's gravity well. Perhaps part of the problem is that you're confusing the OP's intent (to lift something against the force of gravity but not mechanically) with actually changing the effect of gravity, e.g. to stand on but underneath the plate because the plate is creating an attractive gravity that is greater than and contrary to planetary gravity. I'd need Firestryke to clarify, but I don't believe that's what he/she is asking. $\endgroup$
    – JBH
    Dec 8, 2020 at 13:08
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Well, some time ago there seemed to be an accidental discovery of a "gravity shielding" effect in an experiment by Eugene Podkletnov at the university of Tampere in Finland. Created a lot of buzz for a short period and then died, so it was probably nothing, but I have come across arguments why it might be possible according to the known laws of physics.

I believe it involved a spinning magnetic field in a superconductor, reducing the effect of gravity on all objects above it by some small percentage.

Some random links that might help you on your way: https://electrogravityphysics.com/gravity-shielding-finland/ https://en.wikipedia.org/wiki/Eugene_Podkletnov

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No, not in the way these "grav lifts/antigrav lifts" are depicted in the literature.

Surprisingly, this has nothing to do with (anti-)gravity.

A typical scenario would be: you return from lunch, enter the mgea-skyscraper at ground level, step into an "antigrav tube" and move up to your office on the 240th floor, where you and your lunch arrive, quite possibly, separately.

The idea of this kind of life was perhaps inspired by a paternoster lift (https://en.wikipedia.org/wiki/Paternoster_lift), and movement in the lift tube is usually described just like that of paternoster lift, just without cabins.

Now, with constant and human-manageable velocity (the passenger enters and exits the lift on his/her own, by means of a handle), this trip will take some time (let's say 15 minutes for single 240 floor trip). Basically, when you arrive at ground level, you can immediate embark on the return trip to your office because the travel time leaves no time for lunch. Which saves you from the embarrassing situation of you and your lunch arriving separately.

Obviously, one "solution" would be to have constant acceleration (and deceleration) in the grav lift. So, on the trip from your 240th floor office to ground level, you would accelerate for the first half the trip and decelerate for the second half. Mathematically, with about 1 g-force of acceleration, you could expect to arrive in maybe 20 seconds. Practically, you will crash into Guido from the 120th floor after 10 seconds, at a speed of 350km/h. Lunch separation issues are now the least of your worries.

Again, this is about how the lifts are depicted in the science fiction literature. You might add accelerator tubes which bring the passenger up to some fixed travel speed before entering the main tube, and some clever exit system which pulls the passenger out of the main tube upon arrival at the pre-selected destination and slows them down in a separate decelerator tube. But that's far from being as "elegantly simple" as the grav lifts depicted in the literature.

Another solution would be to "bundle" passenger with similar trips (this is actually done in real life right now, to increase the bandwidth of conventional lifts). You might even provide cabins for these "passenger bundles" (groups).

Oh, wait. That's too much like a boring ordinary lift. Note that in very tall building, even the boring ordinary lift already accelerate (and decelerate) at 0.5 g-force - and this is already a bit of a lunch containment issue for some people.

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    $\begingroup$ But having an ~1g acceleration (calibrated to whatever planet you're on) is so convenient. You step in at the bottom and it accelerates you for the first half of your trip and then you simply continue on your trajectory upwards for the second half until you arrive at your destination at a perfect standstill (do be quick about grabbing the hand hold for the exit, because you won't be there long). On the way down you just jump and halfway down the 1g deceleration catches you. Having a different from average air resistance/surface area may result in not reaching your destination...in one piece. $\endgroup$ Dec 8, 2020 at 19:42
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Bonus Answer: Directional Gravity

One issue with gravity is that it's omnidirectional. So if you can generate artificial gravity to lift an object away from the surface of the Earth (meaning 1 g-force of gravity), it would also affect everything else in the vicinity. And that's vicinity on a planetary scale. Basically, it would appear that you just created an Earth-size gravity source, in additional to the already present Earth itself. That sucks. Literally.

The obvious solution is directional gravity (often called a "tractor beam" in the science fiction literature). To provide useful directivity to radiation (radiation like electric fields, or sound emitted/radiated from a speaker), the wavelength of the radiation must be significantly smaller than the dimension of the emitter. Obviously, with higher frequency we have smaller wavelengths, so higher frequencies will work better (like in audio, where higher bass is "hard to direct" and the treble is "hard to get omnidirectional").

We know that gravity waves exist. if we could generate gravity waves with device whose dimension is significantly that the wavelength of our (high-frequency) gravity waves, we could end up with directional gravity waves. That won't be perfect (just look up "antenna directivity" in Google), but it's clearly an improvement over good old omnidirectional gravity.

Now, gravity waves don't help us very much, I guess. If they act like radio or sound waves, they do not move stuff around but cause stuff to vibrate around some position.

All credit goes to jdunlop for mentioning Acoustic Levitation. I currently cannot rule out that gravitational vortices can be generated, just like the acoustic vortices mentioned by jdunlop - and that these could be used as some kind of "tractor beam".

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There's a simple way to solve this: Superconductors. A superconductor is a material that's been chilled to the point where there's little, if any, electrical resistance, and running an electric current through a superconductor produces a powerful magnet. That magnet can be used to provide enough force to negate the weight of an object.

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