[meteorite-list] More data

[mexicodoug]

Tracy wrote:

"Thought experiment... Jupiter is known to have some heavy magnetic fields, 
as well as intense radiation.  Would an iron asteroid spending several 
thousand years or so whipping through Jupiter's magnetic field develop a 
notable magnetism of its own? "

Hi Tracy, Listees (2nd posting attempt),

Probably not magnetized, Great thought either way - and considering even 
stony asteroids containing metal flecking are also included.  The magnetic 
field of Jupiter at it's strongest points near the surface is like being a 
centimeter away from a kitchen magnet (~8 Gauss at one centimeter distance, 
even thought the magnet manufacturer says it is 3000 Gauss, and at the 
surface it is 200 Gauss).  Ever notice how a rare earth magnet is nearly 
useless just two or three centimeters away - same story even though it is 
rated for 15,000 Gauss!

Following Pete's line of thinking, to become magnetized, being in a 
not-to-excessive magnetic field isn't enough, the material (iron asteroid in 
this case) would have to have a net orientation with respect to the magnetic 
flux for the effect to be cumulative.  Like the repeated "stroking" he 
mentions against a magnet in a lab - in the same direction.  There is 
nothing magic about the touching of the object to the magnet while 
"stroking", just that if it touches, you have the most powerful and parallel 
oriented part of the field (radius closer to zero, assuming the magnetic 
field drops off with distance from its center: this effect you can see with 
the drop off mentioned with the kitchen magnet).

In the case of Jupiter, you obviously wouldn't be touching Jupiter's metal 
core (of hydrogen metal), so that would be in the lab like passing 
("stroking") the iron to be magnetized without touching.  It works fine, 
just takes longer and doesn't provide the exposure to the maximum flux 
available (thus, decreases the strength of the resulting induced permanent 
magnetism).

Some questions to ask:

a) How strong is Jupiter's magnetic field?  (maximum already answered, 
Jupiter's magnetic field at any asteroid-whipping distance weaker than 
Earth's field at Earth's surface.)

b)And how does it decrease with distance from Jupiter (the size of the 
field)?

c)Could something pass through Jupiter's magnetic field repeatedly without 
being part of the Jovian System (i.e., without orbiting Jupiter)?

d)Under what circumstances could the passes through Jupiter's magnetic field 
be cumulative and not randomly counterproductive?

e)What is the field strength in the Tail of Jupiter's magnetic field for 
some hapless asteroid caught in plane and between the two giants?

f)Does Jupiter's magnetic field stay stationary at any points (like on Earth 
and Mars, a net moment can be recorded at particular points on the 
surface.)?

g)If caught in a Kirkwood gap, could an asteroid get close enough making 
enough passes, to be magnetized and instead of being captured, be 
slingshotted Sunwards?

h) How close would a piece of iron need to pass to Jupiter to get magnetized 
enough above the noise ratio enough to be observed qualitatively?

Complicated questions - the observation I have:

If Jupiter's toroidal magnetic field has a 10 million kilometer diameter, at 
the edge of the torus, the escape velocity will be about 7.07 km/s, locked 
around Jupiter.  Earth's escape velocity is 11.19 km/s.  Or looked at 
another way, to escape from this weak edge of this 10 million km Jupiter 
field torus, an object is midway (rms) between Mars and Earth escape 
velocity from escaping the rocky planets' ground level.  Beyond the edge, 
there is not much a net field.  Maybe an object orbiting relatively along 
Jupiter's field flux line vectors would be magnetized effectively, if such 
an orbit were possible (if it were polar, would it need to do a flip each 
time it passed one of Jupiter's magnetic poles, haven't though about that.)

So all things considered, along with the fact that Mars has an atmosphere, 
maybe the odds of escaping Jupiters magnetic field (while in orbit) are 
about as likely as meteoroids from Mars, and this is the edge of the field 
where it is weakest.  Not saying impossible!  Saturn has it's own 
asteroid/meteoroid belt - the "rings", so things do collide and something 
might escape if it happened just right ... Incidentally - the same would be 
true for a fragment from Saturn's rings in your thought question.  But the 
only authentic Saturn brought to the list's attention so far was the one in 
Anne Black's driveway, which hopefully never suffered such a collision :-)

One other observation, is that roughly in the plane of the solar system, the 
Sun lifts and pushes back down again her ballerina skirt enough (though at a 
factor perhaps only 1/1000 of what Jupiter could do under optimal conditions 
closer in to the giant planet) to scramble magnetic moments, and to make 
things even more interesting, flips direction every 11 years.  I am thinking 
about this like a rare meteoroid escaping Jupiter being a videotape that the 
Sun incessantly plays, rewinds and fast forwards for millions of years until 
the day we get a piece of Jupiter in our driveway (or in my case, just the 
sidewalk right of way...), and pop it in the VCR and hope for "contact"...

Hope I've not gotten on too shaky ground with your question, but now it is 
time to ask if there is a doctor in the house who can answer it for real?

Best wishes and great health,
Doug

PS, the question on heating from the magnetic field of Jupiter via induced 
electrical current, I think you would need to be way too close to have any 
hope of observing this. Europa is thought to have a metal core, but it is 
shielded by some sort of a conductive ocean.  So the satellite moon has its 
own independent magnetic field. If we take the case of Jupiter's closest big 
satellite, Io, we note it is heated and has volcanos, and is believed to 
have a Ni-Iron core.  But Io's heat was seen to be generated by Jupiter's 
gravitational interaction (frictional compression), and not to have any 
magnetic field of its own - basically being a magnetic slave to Jupiter. 
Still, it is an interesting case, because the volcanos spew ions that 
connect it to Jupiters in an electric circuit in the vast Jovian magnetic 
field, and nearly a million amps are generated!  The other two big moons of 
Jupiter are thought to have basically non metallic cores, so my take-way is 
that any power dissapated from such hypothesized eddy currents is minor 
compared to other interactions with Jupiter.  This is a PS because it is 
based on volcanically shaky ground, but I thought you might appreciate that, 
living life in that neighborhood of Earth :-)


----- Original Message ----- 
From: tracy latimer
To: mexicodoug ; meteorite-list at meteoritecentral.com
Sent: Tuesday, December 04, 2007 1:31 AM
Subject: RE: [meteorite-list] More data



> A secondary argument, is, will magnetic properties persist after 4.5 
> billion
> years of gradual relaxation in the metals (and formation of Widmanstatten
> bands)? Is there a source in the Solar system capable of magnetization? I
> bet you can aswer those well...

Thought experiment... Jupiter is known to have some heavy magnetic fields, 
as well as intense radiation.  Would an iron asteroid spending several 
thousand years or so whipping through Jupiter's magnetic field develop a 
notable magnetism of its own?  Might it also undergo heating from eddy 
currents?

Tracy Latimer





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----- Original Message ----- 
From: tracy latimer
To: mexicodoug ; meteorite-list at meteoritecentral.com
Sent: Tuesday, December 04, 2007 1:31 AM
Subject: RE: [meteorite-list] More data



> A secondary argument, is, will magnetic properties persist after 4.5 
> billion
> years of gradual relaxation in the metals (and formation of Widmanstatten
> bands)? Is there a source in the Solar system capable of magnetization? I
> bet you can aswer those well...

Thought experiment... Jupiter is known to have some heavy magnetic fields, 
as well as intense radiation.  Would an iron asteroid spending several 
thousand years or so whipping through Jupiter's magnetic field develop a 
notable magnetism of its own?  Might it also undergo heating from eddy 
currents?

Tracy Latimer





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Initiative now. Join in! =