Lenz's Law navigational deflector


my solution does not help against "space" weapons like: plasma weapons, laser weapons

(directed-energy weapons https://en.wikipedia.org/wiki/Directed-energy_weapon)


When a spaceship travel at high speed in space, every stone or rock that's standing in the spaceship's path will puncture a hole through the spaceship.


see question by AStopher and answer by Valorum here:


star trek force fields use gravitons which are theoretical particles, which we don't (yet?) have.

in another place they hint to anti-protons. this suffers from the following difficulties: it's very expansive to make (humanity so far made only a few nano grams),

but even if we had anti-matter available, it will explode so hard when it touches the space stone that it will destroy the ship more than the stone ever would.

another impossible solution comes from Prof. Michio Kaku here (thanks to silichip from DailyMotion for the video) :

Physics of the Impossible: How to Build a Force Field?


Kaku suggests we use plasma (which is a gas so hot that the electrons separate from the gas atoms) that you hold with magnets.

one huge problem is: where do you get the energy to heat a gas like that for so long?

another huge problem: in order to produce the magnetic field that holds the plasma, you need a chamber (closed container) around it, and the space stones will hit this chamber and destroy it.

see in Wikipedia about Stellarator (the coil) : https://en.wikipedia.org/wiki/Stellarator  and Tokamak (again the coil) : https://en.wikipedia.org/wiki/Tokamak  .

if the "rings" of the spiral of the coil are not closed but open to the side where the space stones are coming, we can't produce the magnetic field to hold the plasma and it will vent to space.

another huge problem: even though the plasma vaporizes the incoming stone the conservation of momentum still means this burning steam of what used to be stone will hit and penetrate your ship.

next Kaku talks about lasers, making a lases beam crisscross the surface of the spaceship using mirrors.

this suffers from all the above downsides: energy for the laser, one mirror broken by the first spec, and then rest are useless, the burning steam will still hit the ship etc.

next Kaku taks about physically armoring the spacecraft with nano carbon tubes. today they are very very expansive and small, but let's say that in the future they are available:

it would be like a car accident in an old car that doesn't absorb the energy of the collision. the vehicle will survive, but it will pass all the energy to the crew which will die.

Kaku illustrates with swinging golf balls into a chain-link fencing. but in his metaphor the the fence has posts set into the ground (made of steel tubing). this transfers the energy to the ground.

in the real case whatever holds the net in space will not to be rigid so it will transfer the energy of the impact to the spaceship.


How Do Star Trek’s Deflector Shields Work? (Because Science w/ Kyle Hill) - skip to about minute 2:30 .

Kyle suggests deflecting incoming things that have electric charge using Lorentz force.

this idea is mostly good - it solves most of the problems that arise in Kaku's "solutions".

Kyle doesn't explain what's the shape of the spaceship in order to create this field so i will assume the best one i can think of (for the required magnetic field) - a torus (doughnut or bagel shape).


there is no impact at all, no hot vapor with enough momentum to penetrate the ship and no "stiff" non-absorbing crash.

the magnetic field extends outside the spaceship so it doesn't suffer from the "closed container" problem of the plasma.


where do you get the energy to flow electric current around the torus (doughnut) for so long?

maybe instead of an electromagnet we can use a permanent magnet but then it will be so massive that you can't accelerate it and decelerate it (let alone fight a planet's gravity).

another huge problem that is discussed in the video: "what if they have a neutron bomb?", or in other words, the magnetic field doesn't effect objects that don't have an electric charge.

not just neutrons, any object that doesn't have a "net" charge, because it has roughly as many positive and negative particles, this includes all space rocks!

can we "put" electric charge on the incoming object?

The ancient Greeks noticed that amber attracted small objects when rubbed with fur. the Greek word for amber is "electron" (ἤλεκτρον).

but even if we can rub off some electrons from the incoming object it's only on the surface so that's not enough.

can we "give" the object a bigger electric charge?

maybe in the front center of our spaceship we can have an electric rod like when people do demonstrations with a tesla coil, that will shoot lightning at whatever is coming?

this will work only if that object is conducting electricity, and even then not always, because if the object is conducting all around (like a metal rock), it's indise is in a Faraday's cage.

so maybe if we can't effect the inside we can effect the outside? what if can add to each incoming object something with electric charge?

it's not like we have an incoming letter and put it in an envelope, these things might come close to the speed of light. so what we need it a very tough "cup" that will catch it.

this "catcher" can be made from a strong metal like titanium which is very expensive especially considering we can't collect it back after it's deflected.

but we can't just put one little "catcher" because we don't know where the incoming object will be. we also don't know what size the incoming object will be.

so we end up arranging something that looks like a hierarchy of "catchers" in layers: the front most layer has many small "catchers" the size of drinking glasses on a tray. the next layer has fewer but bigger "catchers" the size of buckets. the next layer had even fewer but even bigger "catchers" the size of open barrels. and so on.

let's say a tiny meteorite is incoming, it will be catched by one of the cups and because of the spaceship's magnetic field it will be gradually pushed aside away from the spaceship.

this method also has problems of its own: the layers that are far from the magnet are in weak magnetic field, and also a catcher can flip and "drop" its content (the object) in the direction of the spcaeship.


if the object comes exactly in front of the ring, there will zero deflection because it will be pulled equally to the left and right etc, and it will destroy the spaceship.

this is a low probability scenario but if it happens it's catastrophic - like breaking one mirror in the laser scenario we talked about.


my solution uses the "catchers" system but instead of Lorentz Force that deflects, i use Lenz's Law which works like in the following two videos by MIT and "Sixty Symbols":

so the whole spaceship will be a long tube made of copper.

More Magnets - Sixty Symbols


or the whole spaceship will be a long aluminum tube:

Physics Demo -- Lenz's Law


and because of the currents that are induced in the tube it will slow down the "catcher" that contains the incoming object.


now the "catcher" doesn't need to have electric charge, but instead the catched needs to be a magnet. for example neodymium magnets.

this method keeps has all the advantages of the "Lorentz Force" method, but doesn't have that method's disadvantages:

it doesn't need energy, it's totally passive; we collect the "catcher" after it slowed down the incoming object so the catcher's cost is not important because the catcher is recycled; the "catcher" has no reason to flip because there is no rotation moment because all the forces act along the same line which is along the tube; and finally if the object comes exactly in front of the ring it's still stopped.

after the incoming object was slow down considerably by the Lenz's Law, if it didn't stop completely, it is caught by the next layer of "catchers".

we can make the tube very long, as long as calculations of worst case scenario will show that is needed.

at the back side of the tube will live and work the crew.


after each colission with a space rock the spaceship must reset the "catchers" to their initial location.

i think this means the spaceship has to slow down and stop mechanically move the catchers back into place. since the crew move them slowly there is not a strong force working against the crew.

by the way this elongated shiny shape might be the shape of part of the UFO sightings that look like a cigar!