Why is no one trying to create a UFO-like engine out of superconductors that can levitate in Earth's magnetic field?

[Kassander]

First of all, sorry for my bad English, I am from Austria, so it's not my mother tongue.

I know that an ordinary superconductor could not levitate in Earth's magnetic field because its weight is higher than the force that Earth's magnetic field can carry. But the simple solution is to use superconductors that are hollow inside. This would drastically reduce their weight without reducing their lifting capacity. Even smarter would be to cover a light and solid material with a thin layer or foil of some superconducting material. To increase the stability of the object even more, you can choose a stable structure like a sphere and use struts in an optimized way. This would reduce the weight even more because less material would be needed to keep the structure stable.

I asked ChatGPT how much a hollow sphere with a diameter of 10m and wall thickness of 10cm that is covered with a 1mm layer of superconducting Nb-Ti could carry in Earth's magnetic field. This was its answer:

“The load capacity of a hollow aluminum sphere with a shell thickness of 10cm and a 1mm thick superconducting niobium-titanium layer in Earth's magnetic field can be calculated using the following formula:

where F is the maximum load capacity of the superconductor, μ_0 is the magnetic field constant, V is the volume of the superconductor, and R is the radius of the superconductor.

The volume of the hollow aluminum sphere with an outer radius of 5m and a wall thickness of 10cm can be calculated as follows:

where R_o is the outer radius and R_i is the inner radius of the sphere. Thus, we get:

Therefore, the radius of the superconductor is R = 5m + 0.1m + 0.001m = 5.101m. The magnetic field strength of Earth's magnetic field is about 0.5 Gauss or 0.00005 Tesla. The maximum load capacity of the superconductor can thus be calculated as:

Subtracting the weight of the superconductor, the maximum payload is about 209 tons.”

 

Since I cannot calculate this on my own, I cannot say if this is correct, but if it is, this would be a highly energy-efficient way to transport things since you don't need energy to hold the payload up. Due to the Meissner-Ochsenfeld effect, the object would be locked in the magnetic field lines. I know you could not use the full capacity of 209 metric tonnes because you need an isolation layer and a cooling system, but there would still be a lot of payload capacity available.

A second possible use of this technique would be to reach space with it. Normally, you are locked in the magnetic field lines due to the Meissner-Ochsenfeld effect. However, if you use two or more spheres and switch the superconductivity on and off, you can climb up to space like a gecko. It sounds strange and would look strange for sure, but if the calculations are correct, it would be absolutely possible. Of course, you would not have escape velocity or even enough velocity to reach an orbit, but for cheap and safe space tourism, this would be enough.

A third possible use would be to reduce costs and risks in the re-entry phase of every space-flying object. To decelerate from the high velocities needed for spaceflight, a huge amount of energy is needed. Heat shields such as those seen on the Space Shuttle or Starship are expensive and a huge risk factor in space travel. Due to the Meissner-Ochsenfeld effect, a smaller version of the calculated sphere would decelerate every spacecraft in the re-entry phase. It has to be calculated whether the amount of energy saved because of the deceleration is higher than the amount of energy needed to bring this structure in the spacecraft up to space. But since the enormous amount of energy needed to break through the magnetic field lines when a superconducting object is locked, I'm optimistic that there would be a positive outcome. In the future, when space mining and space manufacturing become topics, this could possibly save a lot of energy and money in bringing goods back to Earth.

So there are three possible ways to use this technology. But why is no one developing it? Or is there something wrong with ChatGPT's calculation?

[exchemist]

3 minutes ago, Kassander said:

First of all, sorry for my bad English, I am from Austria, so it's not my mother tongue.

I know that an ordinary superconductor could not levitate in Earth's magnetic field because its weight is higher than the force that Earth's magnetic field can carry. But the simple solution is to use superconductors that are hollow inside. This would drastically reduce their weight without reducing their lifting capacity. Even smarter would be to cover a light and solid material with a thin layer or foil of some superconducting material. To increase the stability of the object even more, you can choose a stable structure like a sphere and use struts in an optimized way. This would reduce the weight even more because less material would be needed to keep the structure stable.

I asked ChatGPT how much a hollow sphere with a diameter of 10m and wall thickness of 10cm that is covered with a 1mm layer of superconducting Nb-Ti could carry in Earth's magnetic field. This was its answer:

“The load capacity of a hollow aluminum sphere with a shell thickness of 10cm and a 1mm thick superconducting niobium-titanium layer in Earth's magnetic field can be calculated using the following formula:

where F is the maximum load capacity of the superconductor, μ_0 is the magnetic field constant, V is the volume of the superconductor, and R is the radius of the superconductor.

The volume of the hollow aluminum sphere with an outer radius of 5m and a wall thickness of 10cm can be calculated as follows:

where R_o is the outer radius and R_i is the inner radius of the sphere. Thus, we get:

Therefore, the radius of the superconductor is R = 5m + 0.1m + 0.001m = 5.101m. The magnetic field strength of Earth's magnetic field is about 0.5 Gauss or 0.00005 Tesla. The maximum load capacity of the superconductor can thus be calculated as:

Subtracting the weight of the superconductor, the maximum payload is about 209 tons.”

 

Since I cannot calculate this on my own, I cannot say if this is correct, but if it is, this would be a highly energy-efficient way to transport things since you don't need energy to hold the payload up. Due to the Meissner-Ochsenfeld effect, the object would be locked in the magnetic field lines. I know you could not use the full capacity of 209 metric tonnes because you need an isolation layer and a cooling system, but there would still be a lot of payload capacity available.

A second possible use of this technique would be to reach space with it. Normally, you are locked in the magnetic field lines due to the Meissner-Ochsenfeld effect. However, if you use two or more spheres and switch the superconductivity on and off, you can climb up to space like a gecko. It sounds strange and would look strange for sure, but if the calculations are correct, it would be absolutely possible. Of course, you would not have escape velocity or even enough velocity to reach an orbit, but for cheap and safe space tourism, this would be enough.

A third possible use would be to reduce costs and risks in the re-entry phase of every space-flying object. To decelerate from the high velocities needed for spaceflight, a huge amount of energy is needed. Heat shields such as those seen on the Space Shuttle or Starship are expensive and a huge risk factor in space travel. Due to the Meissner-Ochsenfeld effect, a smaller version of the calculated sphere would decelerate every spacecraft in the re-entry phase. It has to be calculated whether the amount of energy saved because of the deceleration is higher than the amount of energy needed to bring this structure in the spacecraft up to space. But since the enormous amount of energy needed to break through the magnetic field lines when a superconducting object is locked, I'm optimistic that there would be a positive outcome. In the future, when space mining and space manufacturing become topics, this could possibly save a lot of energy and money in bringing goods back to Earth.

So there are three possible ways to use this technology. But why is no one developing it? Or is there something wrong with ChatGPT's calculation?

One snag I can think of is that the angle of the Earth's field is steeply inclined. So instead of just floating up or staying where you were, I would have though you would shoot off or slide down at an angle. But I'm not familiar with Meissner-Ochsenfeld effect so I'll have to let someone else check the robot's maths.  

[Kassander]

7 minutes ago, exchemist said:

One snag I can think of is that the angle of the Earth's field is steeply inclined. So instead of just floating up or staying where you were, I would have though you would shoot off or slide down at an angle. But I'm not familiar with Meissner-Ochsenfeld effect so I'll have to let someone else check the robot's maths.  

Yes, in the case of the first possible usage, that could certainly pose a major problem. However, the other two would likely only be restricted by it. But I hadn't thought of that, thank you for the response!

[swansont]

38 minutes ago, Kassander said:

I asked ChatGPT

That’s not a technical resource

[Kassander]

2 minutes ago, swansont said:

That’s not a technical resource

I have also noticed that, which is why I am now asking here 😉.

[swansont]

45 minutes ago, Kassander said:

The volume of the hollow aluminum sphere with an outer radius of 5m and a wall thickness of 10cm can be calculated as follows:

where R_o is the outer radius and R_i is the inner radius of the sphere. Thus, we get:

That wall is 20 cm thick, not 10, and its volume is 62.8 m^2

A solid sphere with 5m radius has a volume of 523.3 m^3

[Kassander]

7 minutes ago, swansont said:

That wall is 20 cm thick, not 10, and its volume is 62.8 m^2

ChatGPT has calculated a volume of 524.7m³, which is exactly the same as the volume calculated by an online calculator for a sphere with a radius of 5m. In the last formula ChatGPT used 5.101m to put this in for the Radius witch is also correct. The last formula should calculate the force required to hold the payload. Therefore, there is no need to calculate the volume of the sphere's wall. In the final sentence, ChatGPT states that after subtracting the weight of the superconductor, a payload of 209t can be calculated. To know the weight of the superconductor it´s necessary to know the volume of the sphere's wall. However, ChatGPT has not shown the calculation for the volume of the wall. I don´t get where are you seeing the 20cm thickness and volume of 62.8 m^2?

[swansont]

25 minutes ago, Kassander said:

I don´t get where are you seeing the 20cm thickness and volume of 62.8 m^2?

Outer radius of 5.1 m and inner radius of 4.9m (5+0.1 and 5-0.1) given in the formula is a thickness of 20 cm, and I calculated it myself.

 

Quote

ChatGPT has calculated a volume of 524.7m³

It’s a language program, not a science program. 

 

30 minutes ago, Kassander said:

ChatGPT states that

It’s not a science program. Don’t expect that anything it says is true.

[TheVat]

Isn't the gauss for lifting any significant mass up in the thousands?

Earth is 0.25 to 0.65 gauss.  

[Kassander]

1 hour ago, swansont said:

Outer radius of 5.1 m and inner radius of 4.9m (5+0.1 and 5-0.1) given in the formula is a thickness of 20 cm, and I calculated it myself.

 

It’s a language program, not a science program. 

 

It’s not a science program. Don’t expect that anything it says is true.

Ah, okay, so this would be the correct calculation:

First, we need to calculate the volume of the wall of the sphere using the formula that ChatGPT provided but did not calculate.

The calculation would be:

((3/4)π)((5+0.01)³-(5-0.1)³=19.09m³

So the volume of the wall of the sphere is V₁=19.09m³.

Next, we need to calculate a second volume to use in the formula that calculates the force. For this, we need the entire space enclosed by the superconductor, which has a radius of 5.01m. According to an online calculator, the result of this calculation is 523.91m³. This is slightly less than the 524.7m³ that ChatGPT calculated, and the 523.3m³ that you calculated, so it seems to be fairly accurate. Thus, we have V₂=523.91m³.

So we need to use V₂=523.91m³ instead of 524.7m³ and a radius of 5.01m instead of 5.101m in the formula for the force. But would this change really make that much of a difference?

[exchemist]

30 minutes ago, TheVat said:

Isn't the gauss for lifting any significant mass up in the thousands?

Earth is 0.25 to 0.65 gauss.  

That's what I would have thought. But it would be nice if someone would care to summarise the Meissner-Ochsenfeld effect and what force it can generate. All I know is that a superconductor repels a magnetic field from its interior, but why this produces a force, in what direction, and of what magnitude for a given field strength, is something I have never studied. I had a quick look on Wiki but it was not very informative.

[swansont]

2 minutes ago, Kassander said:

he calculation would be:

((3/4)π)((5+0.01)³-(5-0.1)³=19.09m³

4/3, not 3/4.

I’m not sure the point of these calculations. The volume V in the equation is identified as the volume of the superconductor, i.e. the niobium layer, which is only 1 mm thick. It will have a volume of 3.14 m^3

But we can’t be sure the algorithm has given a formula that is correct for this situation.

[MigL]

I remember doing thinking, and calculations by hand ( or a slide rule ).
Then computers came along in the middle 80s, and all you had to do was the thinking; computers did the calculating.
I suspect that in a few years ChatGPT, or some similar AI program will also provide the 'thinking' for papers and thesis.
Oh boy !

My understanding of the Meissner effect, is that, according to one of the best theoretical explanations, the London equation, the magnetic field decays exponentially inside the superconductor over a distance of 20-40 nm. It is described by a parameter called the London penetration depth, and is not really an expulsion of the magnetic field.

I am not sure if the superconductor will act as a 'shield' to keep magnetic fields out of its interior, in the case of a superconducting sphere.

[exchemist]

9 minutes ago, MigL said:

I remember doing thinking, and calculations by hand ( or a slide rule ).
Then computers came along in the middle 80s, and all you had to do was the thinking; computers did the calculating.
I suspect that in a few years ChatGPT, or some similar AI program will also provide the 'thinking' for papers and thesis.
Oh boy !

My understanding of the Meissner effect, is that, according to one of the best theoretical explanations, the London equation, the magnetic field decays exponentially inside the superconductor over a distance of 20-40 nm. It is described by a parameter called the London penetration depth, and is not really an expulsion of the magnetic field.

I am not sure if the superconductor will act as a 'shield' to keep magnetic fields out of its interior, in the case of a superconducting sphere.

Will it experience a force?

[Kassander]

21 hours ago, TheVat said:

Isn't the gauss for lifting any significant mass up in the thousands?

Earth is 0.25 to 0.65 gauss.  

 

21 hours ago, exchemist said:

That's what I would have thought. But it would be nice if someone would care to summarise the Meissner-Ochsenfeld effect and what force it can generate. All I know is that a superconductor repels a magnetic field from its interior, but why this produces a force, in what direction, and of what magnitude for a given field strength, is something I have never studied. I had a quick look on Wiki but it was not very informative.

Sorry for my late reply. During my first few days, I could only post five comments per day, so I had to wait.

Before his last calculation, ChatGPT wrote, "The magnetic field strength of Earth's magnetic field is about 0.5 Gauss or 0.00005 Tesla." He correctly included this value of 0.00005T as he multiplied it with the formula. However, I am not sure if he calculated the formula correctly afterwards. I obtained a very small number when I used my calculator, but it's possible that I made a mistake when converting the units.

21 hours ago, swansont said:

4/3, not 3/4.

I’m not sure the point of these calculations. The volume V in the equation is identified as the volume of the superconductor, i.e. the niobium layer, which is only 1 mm thick. It will have a volume of 3.14 m^3

But we can’t be sure the algorithm has given a formula that is correct for this situation.

Sorry, I could not answer earlier because I can only publish five comments a day since I signed up yesterday.

 I told ChatGPT that it made a mistake in the calculation and it figured out the problem without any help. That is what it wrote:

But I have found another problem. When I calculate the formula, the result is

(((4π*(10^-7))(523.91)²)/(2π5.01))0.00005 = 5.4786810^-7.

This is a very small number, but I am not sure if it needs to be converted to another unit. If a conversion is necessary, it may explain how ChatGPT calculated 209t. However, when I asked for an explanation, I received answers with more mistakes. As far as I can see, these answers are completely useless:

17 hours ago, MigL said:

I remember doing thinking, and calculations by hand ( or a slide rule ).
Then computers came along in the middle 80s, and all you had to do was the thinking; computers did the calculating.
I suspect that in a few years ChatGPT, or some similar AI program will also provide the 'thinking' for papers and thesis.
Oh boy !

My understanding of the Meissner effect, is that, according to one of the best theoretical explanations, the London equation, the magnetic field decays exponentially inside the superconductor over a distance of 20-40 nm. It is described by a parameter called the London penetration depth, and is not really an expulsion of the magnetic field.

I am not sure if the superconductor will act as a 'shield' to keep magnetic fields out of its interior, in the case of a superconducting sphere.

According to ChatGPT 1mm should be enough to keep magnetic fields out. I discussed this with him before the calculation and he wrote:

ChatGPT: The thickness of the superconducting layer depends on various factors, such as the specific superconducting material composition and the desired levitation parameters. A rough estimate could be made based on the critical current density of the superconducting material. For example, if we take niobium-titanium (NbTi) as the superconducting material and assume a critical current density of 100 A/mm², then a required area of about 0.01 m² is obtained for a load of 1000 kg. From this, an approximate thickness of the layer can be calculated by dividing the volume of the required material by the required area. For a layer thickness of 1 µm, for example, a required volume of 10^-11 m³ is obtained. With a layer thickness of 10 µm, the required volume increases to 10^-10 m³. However, these values are only rough estimates and can vary significantly depending on the specific circumstances.

Me: So, if we take a 1mm thick layer, are we on the safe side?

ChatGPT: A 1mm thick layer should be sufficient to ensure the superconductivity of the material and enable sufficient load capacity. However, the actual thickness of the layer also depends on other factors, such as the type of material and application. Therefore, it may be useful to conduct further investigations to determine the optimal layer thickness for a specific application.

I asked him again and he wrote:

[exchemist]

1 hour ago, Kassander said:

 

Sorry for my late reply. During my first few days, I could only post five comments per day, so I had to wait.

Before his last calculation, ChatGPT wrote, "The magnetic field strength of Earth's magnetic field is about 0.5 Gauss or 0.00005 Tesla." He correctly included this value of 0.00005T as he multiplied it with the formula. However, I am not sure if he calculated the formula correctly afterwards. I obtained a very small number when I used my calculator, but it's possible that I made a mistake when converting the units.

Sorry, I could not answer earlier because I can only publish five comments a day since I signed up yesterday.

 I told ChatGPT that it made a mistake in the calculation and it figured out the problem without any help. That is what it wrote:

But I have found another problem. When I calculate the formula, the result is

(((4π*(10^-7))(523.91)²)/(2π5.01))0.00005 = 5.4786810^-7.

This is a very small number, but I am not sure if it needs to be converted to another unit. If a conversion is necessary, it may explain how ChatGPT calculated 209t. However, when I asked for an explanation, I received answers with more mistakes. As far as I can see, these answers are completely useless:

According to ChatGPT 1mm should be enough to keep magnetic fields out. I discussed this with him before the calculation and he wrote:

ChatGPT: The thickness of the superconducting layer depends on various factors, such as the specific superconducting material composition and the desired levitation parameters. A rough estimate could be made based on the critical current density of the superconducting material. For example, if we take niobium-titanium (NbTi) as the superconducting material and assume a critical current density of 100 A/mm², then a required area of about 0.01 m² is obtained for a load of 1000 kg. From this, an approximate thickness of the layer can be calculated by dividing the volume of the required material by the required area. For a layer thickness of 1 µm, for example, a required volume of 10^-11 m³ is obtained. With a layer thickness of 10 µm, the required volume increases to 10^-10 m³. However, these values are only rough estimates and can vary significantly depending on the specific circumstances.

Me: So, if we take a 1mm thick layer, are we on the safe side?

ChatGPT: A 1mm thick layer should be sufficient to ensure the superconductivity of the material and enable sufficient load capacity. However, the actual thickness of the layer also depends on other factors, such as the type of material and application. Therefore, it may be useful to conduct further investigations to determine the optimal layer thickness for a specific application.

I asked him again and he wrote:

To be honest I think to make progress in understanding this topic we should forget ChatGPT and have one of our physicists talk us through the Meissner-Ochsenfeld effect a bit. ChatGPT is basically as thick as mince and just plagiarises stuff it looks up on the web that it hopes is relevant, based on some algorithm. There's no reason to expect it to  be able to do this stuff properly. But does it give you references for where it gets its formulae from? If we can read those sources we might get somewhere.

Meanwhile, I've had another look at the Wiki article, which gives a remarkably simple formula for something called the "magnetic pressure" that a magnetic field exerts on a superconductor. This is Pmag  = B²/μ₀, where P is force per unit area at the superconductor/field interface, in Pascals, B in Tesla. Here's the link: https://en.wikipedia.org/wiki/Magnetic_levitation

What happens if you plug in the numbers for the Earth's field? 

 

 

  

[swansont]

2 hours ago, Kassander said:

According to ChatGPT

You are wasting our time by quoting a linguistic AI when trying to do science.

[studiot]

To be brutally honest this whole proposition reminds me of a mid 20th century science fiction story about a company called General Services Inc.

They were engaged to provide anti gravity (gravity shielding) vehicles for visiting dignitaries from other planets with greatly different gravity than Earth's.

They too came up with a magical-mystical secret formula to solve the problem in time for the visit.

I am not sure of the author I think it may have been Robert Heinlein.

[Phi for All]

4 hours ago, Kassander said:

However, when I asked for an explanation, I received answers with more mistakes. As far as I can see, these answers are completely useless:

!

Moderator Note

Very good. We've established that ChatGPT is NOT a good tool for science discussion. Can we continue to discuss the concept you mention in your OP, or is it dependent on the linguistic AI?

 

[exchemist]

I've come across an explanation , which I don't fully understand, for why a superconductor in a magnetic field experiences a force (the Meissner effect). It is said that eddy currents will be triggered in the superconductor which will form a perfect mirror image of the magnet, with like poles adjacent, so a repulsive force is generated. 

What I don't follow about this is I thought eddy currents were generated by a change in magnetic flux density, not by a static field.

Does anyone know more? 

Edited April 5, 2023 by exchemist

[swansont]

39 minutes ago, exchemist said:

What I don't follow about this is I thought eddy currents were generated by a change in magnetic flux density, not by a static field.

Does anyone know more? 

That true for a conductor, via Faraday’s (and Lenz’s) laws. A purely classical effect.

[TheVat]

3 hours ago, studiot said:

To be brutally honest this whole proposition reminds me of a mid 20th century science fiction story about a company called General Services Inc.

They were engaged to provide anti gravity (gravity shielding) vehicles for visiting dignitaries from other planets with greatly different gravity than Earth's.

They too came up with a magical-mystical secret formula to solve the problem in time for the visit.

I am not sure of the author I think it may have been Robert Heinlein.

"We Also Walk Dogs" 

- by RAH, yes.  

[exchemist]

25 minutes ago, swansont said:

That true for a conductor, via Faraday’s (and Lenz’s) laws. A purely classical effect.

Is a superconductor different, and if so why would that be?

[Genady]

1 minute ago, exchemist said:

Is a superconductor different, and if so why would that be?

Perhaps the eddy currents are generated when the superconductor first placed into the field or when the field is turned on. After that they just keep running because of the superconductivity.

[exchemist]

4 minutes ago, Genady said:

Perhaps the eddy currents are generated when the superconductor first placed into the field or when the field is turned on. After that they just keep running because of the superconductivity.

Can’t be that or the  magnetic pressure would be a function of how the field was applied.