Drude

I was watching TV and I suddenly tumbled across a discovery program(I presume it was discovery channel) that showed use of high intensity laser to cause deviation in path of an oncoming asteriods in space in order to give a it a little deviation angle while in space , to prevent it from crashing into earth and then I did a little brain storm and came up with the following:

we know that electromagnetic waves obey the relationship E/B = c (where E is the electric field and B is the magnetic field).

we also know that according to the works of James Maxwell, and Rudold Hertz, the intensity (or average energy per unit area) of any electromagnetic radiation is given by the follwoing expressions:

Intensity = U/A.t = Emax . Bmax / 2. mue. c Where mue =4pi * 10^(-7)

since we know E/B=c we can deduce the followings:

U/At = Intensity = Emax . Bmax / 2. mue. c = Emax^2 / 2.mue.c = c . Bmax^2 / 2.mue

Now lets assume that we need to suspend a mass of "m" against the gravitational pull of the gravity of a planet with gravitational constant of "g"

we know the weight of the object is F(mas) = mg = W

we also know that in order to suspend the particle we need to apply an equal force in the opposite direction; now, lets ASSUME that I intended to use a laser light (a form of electromagnetic radiation) to counter balance the weight of the object.

It would be logical to call this counter balancing force F(em) or F(electromagnetic). Based on Newton's laws we have:

F(em) = F(mass)

or in other words weight equal the electromagnetic force,

we have then,

F(em) = m . g (Formula 1)

now lets also use the momentum relationship and conclude that any force of F is related to a momentum in a time frame of t, by the relationship F = p /t ; in other words Impulise = F . t = Change of momentum = p

Since this law is universal it applies to the F(em) and we have:

F(em) = p /t , and substituting this in formula 1 we have,

delta(p) / delta(t) = m . g (formual 2)

Now, lets go back to James Maxwell and Rudolf Heinrik Hertz for a second and recall that they proved that if an electromagnetic radiation hits a surface , upon impact it would leave an "electromagnetic pressure" on the surface. In other words, upon contact a momentum is delivered to any surface and that momentum is given by the expression: p(absportive sruface) = U / c , and p(reflective) = 2U /c

therefore we can say that delta(p) or change of momentum is equal to 2U/c for a reflective surface. Replacing inside the formual 2 we have:

2U/(c.t) = m . g

or in other expression,

U/t = m . g . c . 1/2 formula 3

we also konw that intensity of any electro-magnetic wave is given by (as mentioned before):

U/A = Intensity = Emax . Bmax / 2. mue. c = Emax^2 / 2.mue.c = c . Bmax^2 / 2.mue

so (U / At) . A = Intensity . A = U/ t = A. c . Bmax^2 / 2.mue

replacing the ebove in formual 3, we have:

A. c . Bmax^2 / 2.mue = m . g . c . 1/2

or in other expression of the above formula we have,

QUOTE
Bmax = Radical { (m . g.  mue)/ A }
formula 4

The above formula means that in order to suspend a mass of "m" in a place of gravity of "g", we need an electromagnetic ray of Bmax which acts on a ideally reflective area of A we have to obey the formual above.

Now , the prupose of my post was to ask a series of questions

1)why cant we then, float objects by use of strong magnetic fields?
2)if floating of an object is possible, then why cant we make "hover" shoes that use high energy gamma radiation? [ignore the biological effects, just the fysical barrier]
3)I also thought we could used this to move space ships in space, where "g" is so small it almost approaches 0 , to propell space ships using solar winds or even simply sun rays.
4)I spoke with a well known physicist about this and he asserted that though it is very possible, in reality we ca not create Bmax of such high values (the values needed for B max is very large...try puting your own weight and see!). I asked him however, why we can not use black holes in space for this purpose and frankly he didnt have any answer. So what do you think?

(Rest assured however, all formuals are right and you can find them in Physics by Serway, Cuttnell, College physics, Qunatum physics version I, and also in Encylopedia physics online).
Guest
Phil look at all this stuf, Dru has printed and blinks eyes.
icecycle
The math makes my brain hurt.
(I am eventually going to ask a math question; it will be very stupid; trust me.)

OK, to turn that asteroid you would use reaction mass from abolative heating of the surface; light pressure just won't do.

You can use a magnetic field to float something , however, the magnetic field is very strong. Sometimes the magnetic apporatus breaks.

Gamma radiation, see above, light pressure will not do.

Hover boards, et all.

It might be possible to use Meisner effect, if you were above a terrain that allowed temporary magnetic effects to be applied, in the case of substances only having paramagnetic qualities, too much power would be required.
rpenner
The dimagnetic properties of living tissue are such that a 10-20 tesla field is needed to counterbalance the weight of a very small frog.

IgNobel Prize, 2000

From the High Field Magnet Laboratory at the University of Nijmegen:

The Frog That Learned to Fly (Molecular Magnetism and Levitation)

Levitation Movies

The same source states that 33-60 Tesla is the current state-of-the-art for very small bore solenoids, so the only magnetic levitation of a human I have seen is a Sumo wrestler standing on a plate of high temperature superconductor over a magnet. (or was it vice-versa). Anyway, dimagnetism is very weak compared to superconducting Meisner effect.
Drude
QUOTE
The dimagnetic properties of living tissue are such that a 10-20 tesla field is needed to counterbalance the weight of a very small frog.

IgNobel Prize, 2000

From the High Field Magnet Laboratory at the University of Nijmegen:

The Frog That Learned to Fly (Molecular Magnetism and Levitation)

Levitation Movies

The same source states that 33-60 Tesla is the current state-of-the-art for very small bore solenoids, so the only magnetic levitation of a human I have seen is a Sumo wrestler standing on a plate of high temperature superconductor over a magnet. (or was it vice-versa). Anyway, dimagnetism is very weak compared to superconducting Meisner effect.

Very useful info . Thank you. Seeing this , it makes me believe that such technologies are not far from reality. In fact I even guess that the saucer sight seeings could be some kind of military machine using the same floating mechanism.

QUOTE (->
 QUOTE The dimagnetic properties of living tissue are such that a 10-20 tesla field is needed to counterbalance the weight of a very small frog.IgNobel Prize, 2000From the High Field Magnet Laboratory at the University of Nijmegen:The Frog That Learned to Fly (Molecular Magnetism and Levitation)Levitation MoviesThe same source states that 33-60 Tesla is the current state-of-the-art for very small bore solenoids, so the only magnetic levitation of a human I have seen is a Sumo wrestler standing on a plate of high temperature superconductor over a magnet. (or was it vice-versa). Anyway, dimagnetism is very weak compared to superconducting Meisner effect.

Very useful info . Thank you. Seeing this , it makes me believe that such technologies are not far from reality. In fact I even guess that the saucer sight seeings could be some kind of military machine using the same floating mechanism.

The math makes my brain hurt.
(I am eventually going to ask a math question; it will be very stupid; trust me.)

OK, to turn that asteroid you would use reaction mass from abolative heating of the surface; light pressure just won't do.

You can use a magnetic field to float something , however, the magnetic field is very strong. Sometimes the magnetic apporatus breaks.

Gamma radiation, see above, light pressure will not do.

Hover boards, et all.

It might be possible to use Meisner effect, if you were above a terrain that allowed temporary magnetic effects to be applied, in the case of substances only having paramagnetic qualities, too much power would be required.

Thanks for the info. however I am pretty sure that in free space ether when an asteroid has no acceleration (net force is zero) a ray of high intensity laser can easily cause it to gain an angle of deviation and barely miss the earth.

The force of impact
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