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Building a Miniature Magnetic Earth
Doofus writes "There was an interesting story on NPR this morning about a geophysicist who has constructed a miniature earth to model the earth's dynamo effects.
Dan Lathrop, a geophysicist at the University of Maryland, has constructed a 10-foot diameter stainless steel sphere. He intends to fill the sphere with molten sodium and spin the sphere to examine the propensity for the system to generate its own magnetic field.
The article includes both video, in which Lathrop spins up the sphere, and audio, including the conversion of magnetic wave functions in prior experiments into audible sound: literally the music of the spheres."
I have seen this before in a Discovery Channel show.
Miniature earth? Stainless steel? I know it's been a while since I took my geology courses, but the Earth isn't made of stainless steel IIRC. And the phrase "harmony of the spheres" has a much more poetic ring to it.
Wait, don't fill it up with anything. The model is accurate right now!
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We're going to go create our own dome, a dome within a dome. So don't come knockin on our door!
Hasn't he been doing this for awhile now? I am fairly certain I have already watched the documentaries of this machine in action.
A 10-foot sphere filled with sodium? Damn... talk about playing with fire.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
But while nature has an easy time making magnetic So, yeah -- he's been trying (but failing) for a while.
Couldn't he have gone to the local fairground and used one of those cyclotron things where you get stuck to the side of a giant drum? Take the people out, fill it with sodium. Or one of those candy sugar spinny things that makes clouds on a stick? They're awesome. Science is awesome and has lots of sugar. Wait, salt is sodium chloride, he could make candy floss out of salt? What has science done!
Task Mangler
A group at New Mexico Tech was working on a similar experiment using a cylindrical chamber filled with liquid sodium and a way to introduce turbulence to create magnetic fields. This was started over ten years ago. Their group page is a bit out of date, though.
My first thought upon reading the summary here was "Man, I really hope they disabled the sprinkler system...
What I'm listening to now on Pandora...
...the start of a howie mandel joke?
Well, sass that hoopy. Bypass construction notwithstanding, should be an interesting project. Frood really seems to know where his towel is at.
(Too easy)
But while nature has an easy time making magnetic fields, scientists do not. This is Lathrop's third attempt. there we go. but the point still remains, yes - he's tried and failed before. Hopefully this time he'll manage it.
we can throw it in a lake when he's finished? That's a *lot* of sodium.
Do you have ESP?
You fools, you are all wrong. The truth is that we live IN the hollow earth!
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
I saw the documentary too - they've been been mucking about with magnetic fields for a very long time; although their approach seems to be very accident prone. This should clarify things a bit:
http://www.youtube.com/watch?v=KfoXOydWFMM
Namaste, and good luck.
shouldn't you be commenting on youtube videos or something?
Don't drink and post.
This guy now seems to bring this "sodium party" thing to a new, unprecedented level...
What the heck is wrong with them, didn't they ever see "The Core"?????
ARGH!!! They're going to screw up the magnetic fields and we're all going to d... er... never mind.
Sig?
M=D x V
M=0.97g/cc * 14,826,654cc = 14,381,854.38g = 14,381.85438kg ~ 14.4 tonnes
It sounds like you're dating the wrong guys. Maybe you need to raise your standards.
Swiss Cheese is both flat and hollow.
When our name is on the back of your car, we're behind you all the way!
He's got Balls of Steel!
-- Who is the bigger fool? The fool or the fool who follows him? --
Class D fires are not fun.
You're not doing them right, then.
When our name is on the back of your car, we're behind you all the way!
It has been proven by the Wisest Human on Earth, Dr. Gene Ray that the world is a CUBE!!
Education vaporized your brain by not being taught the four corners of CUBIC CREATION!!!
I think you may have a dodgy calculator - using your figures, I get:
10 foot dia = 1.52m radius
vol = (4/3)*PI*R^3 = 14.8 m^3 = 1.48 * 10^7 cc
Comes to just over 14 metric tonnes of molten sodium, which is frankly disappointing: I put more than that in a good hot curry.
I gotta wonder if they thought about installing and FM-20 or other extinguisher system in the room, and disabled the sprinklers. If they didn't, someone let me know what building it's in so I can stay away. Far away.
"As God is my witness, I thought turkeys could fly." A. Carlson
Don't you need the solid iron core, so that you have the 2 iron pieces separated by the liquid (sodium) mantle ?
I want to delete my account but Slashdot doesn't allow it.
Oh, never mind - should have RTFA.
"As God is my witness, I thought turkeys could fly." A. Carlson
It would be music of the sphere. Singular. Sounds much less enchanting for some reason. Must be an innate preference for plurality.
Invenio via vel creo
use water to put out a sodium fire. Water is pretty impressive at conducting heat away, even if it is reacting at the same time.
You just have to use a lake-full!
So, how is spinning a neutral liquid metal going to create an electric field?
Are they hoping that rotating Sodium will be like moving a solid piece of Iron through the magnetic field of the earth, inducing current in the Sodium, which then creates a secondary EMF, which then creates a secondary magnetic field...?
Without Earth's magnetic field are they lifting themselves by their own bootstraps?
Running with Linux for over 20 years!
Andy
Sounds like an interesting experiment. However, I have to wonder how accurately it can possibly represent the mechanisms in Earth's core. Just a few things off the top of my head:
I wouldn't be surprised if some kind of magnetic dynamo CAN be created on this small scale, but I'd hesitate to directly apply anything learned here to the physics at Earth's core. Still, worth doing. Just be careful with the sodium. Why not use mercury? At least you could do it at room temperature.
Dr. Lathrop is hiring Hilary Swank to drill into the core of the sodium to get it spinning ... for added realism. yup
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I hope they remember to dry it out before they put in the sodium.
"How to Do Nothing," kids activities, back in print!
A miniature ball with its own force of gravity. Who else thought this is a Katamari Damacy in the making?!
I noticed the article mentioned the Earth's internal turbulence. Would the way the Sun's and Moon's gravitational pull deform the earth's geometry be a partial cause of turbulence within the earth's molten core?
If no, why not?
If yes, is this experiment accounting for something like that?
Would something like this even have an effect on the magnetic field?
Several groups such as Glatzmeir at Harvard have tried computer simulations. Since it is a non-linear, turbelent phenomena they have to make a very small grid with a large number of grid cells. It took 80 days of NSF supercomputer time in the mid-1990s.
Plus there are some uncertainties:
(1) The equations of state at the high pressures and temperatures inside the earth arent well known. People have squished minerals in diamond presses or in super-guns to measure the equations of state. However a Berkeley group claims the inner-most core is twice as hot as others claim. A factor of two uncertainty is not good.
(2) The coupling of elastic equations with magnetic equations is not well thought out either. People have done each independently fairly comprehensively, but not both together.
The Harvard guy got some interesting results:
(1) There is an inter-play between the solid inner iron core and liquid iron outer core. The solid holds magnetisation better than the liquid. So he sees over a hundred thousand year simulation a "flickering" as the field looks like it might reverse then really doesnt. Then eventually it reverses about every 40,000 years. This is a little faster than observed in rocks. Currently the earth's magnetic field is abotu 10% weaker than meaured right around 1800. People think is this more likely a "flicker" than an impending reversal, but who knows?
(2) The model predicted convection spins the whole core once time extra about every 400 years. Convection is driven by both thermal and magnetic force. Seismologists have looked for this "extra core day" and think they have found it. There has been comprehensive global seismic data for about 45 years, or about a tenth of a rotation. Seismologists have see inner core velocity anomalies moving about this rate. You know a theory is really fabulous when it predicts something completely unexpected such as extra core days, and then scientists verify it.
to simulate the thing (how novel) and of course, it would run Linux!
Hackers have long memories. It works both ways.
n/t
I just read Slashdot for the articles.
I was reminded of the novel "Richter 10" by A. C. Clarke and Mike McQuay, where they use a somewhat similar (albeit much more complex) device to predict earthquakes.
"When information is power, privacy is freedom" - Jah-Wren Ryel
The major flaw in this model's design is gravity, on two levels. One level being that the sphere doesn't exert gravitational effects on itself because it is too small in mass. The other level is that the sphere is under the gravitational pull of the earth.
The only way to negate the latter would be to put the 10-ft sphere experiment in orbit.
I'm no geophysicist, but I have a hunch gravity has a huge impact on the equation when it comes to the generation of the Earth's magnetic field.
Authority questions you. Return the favor.
Great Balls o' FIRE....
(well, if he's standing too close..."
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
One'd think that the cognizant city, state, county, and federal agencies would have building plans prior to issuing permits, and emergency plans for emergency response.
...
i would think there'd have been a requirement to install Halon 1301 or its successor/s (but not PKP, due to nasty corrosion effects...) to trip after evacuation of personnel. With all those magnets around, a magnetic trip mechanism could work if mechanical linkages fail or are burned out, releasing the agent.
(Assumption here) For a fire department to arrive without KNOWING the particulars of the site, and not using time en route to ascertain the particulars is not very effective -- IF that is the case here. Still, employees of such facilities need to be REQUIRED to be first responders.
http://www.periphman.com/fire/fire-suppression-systems.shtml
http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=5vd&q=halon+fire+suppression+system+corrosion&btnG=Search
But, i know when aboard ship, we were trained that if the helo crashed on our flight deck, and the fuel tanks ruptured and ignited due to friction or electrical ignition, the landing gear (made of alloys... magnesium and or titanium, IIRC) WOULD burn like hell and there was no point in trying to salvage the helo NOR in trying to suppress the fire. The main recourse would be to use a forklift or brute manpower to jettison it. Failing that, the ship would have to make hard rolls at speed (assuming we were underway AT a decent clip) and toss it off that way. Otherwise, the bird would burn down into the hull very quickly and then there'd be NO removal and it would continue to burn down into the hull.
For INSIDE fires involving exotics, sand and constant water deluge could COOL, but not necessarily extinguish the burning. The danger there is that aboard ship (particularly one not underway (not moving; AT SEA doesn't mean "underway", a ship not making headway (forward movement) is either anchored, station-keeping, or if stopped, "underway with no way on"...), shipping (taking on) huge amounts of shifting ballast (fire-fighting water) could lead to stability issues or restricted maneuvering to keep it inside flooding boundaries or to manage drainage.
http://www.chaoticsynapticactivity.com/2006/05/17/the-morning-of-the-attack-on-the-uss-stark-ffg-31/
Fire Fighting Appliances
http://www.mcaorals.co.uk/Firefighting%20Appliances.htm
Stability
At Shipboard Fires
http://www.marinefirefighting.com/Pages/Newsletters/Newsletter6.htm
THE IMPACT OF THE USS FORRESTAL'S 1967 FIRE ON UNITED STATES NAVY
http://www.stormingmedia.us/30/3019/A301924.pdf
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
Hmmm. Filling it with liquiid sodium would make some fairly violent volcanoes if a leak ever arises!
There's a eutectic alloy of sodium and potassium that's liquid at room temperature. I guess they're not using gallium, which is safer than sodium, because it's incompatible with steel.
But isn't there a question begging to be asked. Since when is the Earth's core made of sodium? Anyway most of the papers that said you could have used this metal to physically model the Earth's core have been withdrawn. And if you use any iron alloy they lose all magnetic properties when heated to a few hundred degrees C. No one has ever gone beyond this. Oh,I know there are great computer simulations out there, but having done some myself I know that the more complex they become the more they resemble warcraft.