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#26 2012-05-08 23:05:17

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Artificial Magnetosphere - Electromagnetic Induction

GW Johnson said:

Might it not be easier to just replenish atmospheric gases every few centuries-to-millennia with asteroid/comet impacts,  than to attempt planetary engineering on the scale of adding a massive moon?  Or building a planet-girdling conductor and energizing it?  Just the odd thought from an old guy.

Well I agree that that is closer to our actual scope of abilities, so you are not wrong.

However placing a moon into a geosynch and bonding it by gravitation does present the possiblity that the spin of the planet Mars can be used to generate large amounts of power as the apparatus attached to that moon cuts the magnetic lines of force of the plasma from the sun.

On the other hand if it did slow down the crust and create a magnetic field, that magnetic field could not extend to geosynch or it would choke off the process.

But the captured moon notion is for a race of beings beyond human kind I would think.  If humans ever achieved that, then they would have graduated to a new level in my opinion.

So, I think you may be quite correct, long before that achievement the most likely method could be to capture asteroids into Mars orbit, and cook the volitiles out of them with solar concentrators, to produce a thicker atmosphere.  But then you are left with the metals and slag.  Why not make a artificial moon, make it big, and make it multi compartment hollow for habitation?  It might be a long time before it was large enough to actually be used to slow down the Martian crust, but well talk is cheep, and I will be a long time gone before anyone makes those decisions.

Spacenut said:

The internal heat of the planet is probably produced by the radioactive decay of potassium-40, uranium-238 and thorium-232 isotopes.

Well, I will agree that those are big.  However I am also inclined to entertain the notion that:
1) Photons striking the sunlit side of a planet cause a different electical charge than the dark side has, and I expect ground currents to run deep into the Planet, producing heat.
2) I expect that the solar wind which is magnetic and very energenic induces currents into the Earth and Mars, in diferent ways, because Earth has a significant magnetic field and Mars does not.  However, Mars must have significant feromagnetic metals that are not oxidized, and further down, other materials under heat and pressure may exhibit magnetic properties.

As you know Europa and Io use tides to heat up. 

Until recently that might not have been thought of either.

So, if this were to prove true, then Volcanism is caused not only by radioactive decay, but by electrical discharge due to solar energy, and also the solar wind.

So, if this were true, then it is possible that the Earth could remain habitible to life even after the heat from radioative decay is greately deminished.

If this were true, it would also indicate that Mars, and the Moon would be hotter inside than the radioactive decay theories predict.  I could be wrong, but I think that that may already have been confirmed for the Moon.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#27 2012-05-09 23:16:58

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Artificial Magnetosphere - Electromagnetic Induction

One of the wonderful things about NewMars is no matter how grandiose my ideas, someone will out-do me. My idea is to use a planet circling conductor, not to generate the magnetic field directly, but to manipulate currents in the planet's outer core. Some think that's too grandiose; creating an artificial moon definitely out-does me.

Ok, let's look at numbers. Earth's mass 5.976e+24 kg. Mass of Luna (Earth's moon) 7.349e+22 kg. Ratio of the two is 81.3:1.
Mass of Mars 6.421e+23 kg. Mass of Ceres (largest asteroid in our solar system) 9.43e+20 kg. Now say you move Ceres into Mars orbit (I have no idea how), and crash both Deimos and Phobos into it. Deimos mass 1.8e+15 kg, Phobos 1.08e+16 kg. The new moon would have a total mass of 9.430126e+20 kg. In other words the two moons of Mars would not add anything significant. The ratio of Mars to this new moon would be 680.9:1. Gravity dissipates as the inverse square of distance, so it would have to be 1/2.894 the distance between Earth and our Moon. Mean distance from Earth to the Moon is 384,400 km, so this new moon would have to be 132,826.9 km from Mars. Phobos is 9,380 km from Mars, and Deimos is 23,460 km, so it's possible. In fact you wouldn't have to crash Phobos or Deimos, just move Ceres. But how do you do that?

When discussing asteroid mining, I keep saying we know how to move a mountain on Earth: one truckload at a time. You don't move the mountain to a city, you mine the mountain in place. Gold mines smelt ore at the mountain, then deliver 98% pure gold bars to a refinery for further processing. We would do the same thing, bring smelted gold bars back to Earth. Even if you could move an asteroid into Earth orbit, it would be a very bad idea. If you miss, an asteroid impacting the Earth would be very very bad. Now you want to move the largest asteroid in our solar system into Mars orbit. Uhhh...

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#28 2012-05-09 23:31:10

RobertDyck
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Re: Artificial Magnetosphere - Electromagnetic Induction

Spacenut wrote:

The internal heat of the planet is probably produced by the radioactive decay of potassium-40, uranium-238 and thorium-232 isotopes.

Actually, most people believe the core of a large planet like the Earth is a natural nuclear reactor. Neutron radiation will breed uranium-238 into uranium-239, which decays in minutes into neptunium-239, that decays in hours into plutonium-239, and that is fissile. Neutron radiation will breed thorium-232 into thorium-233, which decays in minutes into protactinium-233, which decays in about a month into uranium-233. U-233 is more fissile than U-235. Heavy elements will tend to sink to the core, so it's highly likely there's a natural reactor there. In fact, I've been told the largest uranium deposit in Canada has never been mined. The reason is it's a low level reactor, producing a lot of radiation. Human miners can't approach. Since that exists in the crust, it's highly likely a large one exists in the core.

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#29 2012-05-10 18:28:21

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

I am reminded of a post that was made with a friend of the past that frequented here ....I believe that there are 7 natural nuclear reactors

http://en.wikipedia.org/wiki/Natural_nu … on_reactor

http://geology.about.com/od/geophysics/a/aaoklo.htm

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#30 2012-05-14 20:43:37

RobertDyck
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Re: Artificial Magnetosphere - Electromagnetic Induction

It was interesting to see how much farther Ceres would be from Mars to have the same relative effect that Luna does to Earth now. Ceres would be much farther from Mars than Deimos. So let's try that with Vesta: mass 2.5907e+20 kg. Mass ratio of Mars to Vesta is 2478.48:1. It would have to be 1/5.521 as distant as Luna. That puts it 69,620.3 km from Mars. Deimos is 23,460 km from Mars, so it's still pretty far out. That would orbit Mars every 6 days 22 hours 12 minutes 47 seconds. The calculation for Ceres would orbit Mars every 17 days 15 hours 39 minutes 27 seconds.

Putting Ceres in orbit about Venus: 25,282 km. That would orbit Venus every 16 hours 58 minutes 48 seconds. Wow

Last edited by RobertDyck (2012-05-14 20:52:38)

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#31 2012-05-14 23:05:43

RobertDyck
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Re: Artificial Magnetosphere - Electromagnetic Induction

I wonder. The idea of moving the largest asteroids got me thinking. One proposal to deflect an asteroid was to use material from the asteroid itself as propellant. A giant rocket. To ensure we don't consume the mass we want as a moon, it would require high specific impulse. High temperature can break down rock, a kiln to make cement will break calcium carbonate to CO2 gas and metal oxides. I have also thought a fusion power reactor requires inertial confinement, not magnetic confinement. After decades of research, all experimental nuclear fusion plants consume more energy than they produce, it's time to conclude that approach doesn't work. But a torus with hot gas, not plasma, would not require magnetic confinement. Constrict the gas at one point to accelerate it, like a wind tunnel, and accelerate above the speed of sound to deliberately create a shock wave. Shape the shock wave as a cone with wide end at the Venturi walls so it focusses at a point. That point in the shock wave will increase pressure and temperature to plasma. Engineer it so the gas is at fusion ignition at that point. So the hot plasma will be surrounded by gas alone, nothing solid. Fusion will act as the flame of a torch. Once the gas is past that "fusion torch", it will expand. Not just expand to gas, but significantly expand to cause thermodynamic cooling. Line the walls of the fusion torus with high temperature ceramic down stream of the torch, and inconel everywhere else. Inconel is nickel chrome alloy, able to withstand temperature even higher than titanium alloy. It's heavier than titanium alloy, as heavy as steel. Now what if we take some of this super heated gas, and create a secondary "fusion torch" with ground rock powder injected into the stream. Would it break down minerals into elements, and vaporize metal? Silicon boils at 2900°C, aluminum at 2519°C, magnesium 1090°C, calcium 1484°C, sodium 883°C, potassium 759°C, and of course oxygen at -182.9°C. These are typical elements in rock; at least plagioclase feldspar common in basalt. Of course temperature high enough to vaporize metal would melt any exhaust cone. We could use thermal decomposition to first release gas such as oxygen, producing a partial oxide like SiO. That can happen at 700°C. Then create laminar flow inside the exhaust nozzle so that not-so-hot gas flows between vaporized rock and the exhaust nozzle. The nozzle itself would require regenerative cooling. If we could achieve thousands of seconds Isp with strong thrust using rock as propellant, we might be able to move an asteroid. How much deuterium would the fusion reactor require? If gas from the "fusion torch" is not recirculated, it would require close to 100% fusion to be fuel efficient. That's why I was thinking a fusion reactor would be a contained torus, recirculating fusion fuel. Low reaction rate would be Ok, the gas would come around again and again. But how do you get the heat out to vaporize rock?

::Addition:: Silicon dioxide is particularly resistant to high temperature, it doesn't decompose but boils to gas at 2,230°C. Aluminum oxide boils at 2,977°C. The Space Shuttle Main Engine was known as SSME by NASA, and as RS-25 by the manufacturer. Temperature in the combustion chamber reaches 3,315°C. Although the Shuttles have been decomissioned, the engines are being recycled for SLS, so I can use the present tense. The point is rock as propellant is possible.

Last edited by RobertDyck (2012-05-30 23:32:55)

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#32 2012-05-20 20:58:31

SpaceNut
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From: New Hampshire
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Re: Artificial Magnetosphere - Electromagnetic Induction

It dawned on me that the remant field might be able to first be reinforced to aid in allow for a partial field to protect the crew while working for a more permanent one. I am still puzzled by how the field intensity and the lines of flux actually are shaped...wth regards to the orbital axis...

http://science.nasa.gov/science-news/sc … st31jan_1/

http://www-ssc.igpp.ucla.edu/personnel/ … /mars_mag/

http://mgs-mager.gsfc.nasa.gov/Kids/magfield.html

http://www.bing.com/images/search?q=Mag … ORM=IDFRIR

http://denali.gsfc.nasa.gov/research/pu … 901W01.pdf

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#33 2012-05-26 05:31:40

JonClarke
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From: Canberra, Australia
Registered: 2005-07-08
Posts: 173

Re: Artificial Magnetosphere - Electromagnetic Induction

RobertDyck wrote:

Actually, most people believe the core of a large planet like the Earth is a natural nuclear reactor. Neutron radiation will breed uranium-238 into uranium-239, which decays in minutes into neptunium-239, that decays in hours into plutonium-239, and that is fissile. Neutron radiation will breed thorium-232 into thorium-233, which decays in minutes into protactinium-233, which decays in about a month into uranium-233. U-233 is more fissile than U-235. Heavy elements will tend to sink to the core, so it's highly likely there's a natural reactor there. In fact, I've been told the largest uranium deposit in Canada has never been mined. The reason is it's a low level reactor, producing a lot of radiation. Human miners can't approach. Since that exists in the crust, it's highly likely a large one exists in the core.

Evidence that "most people" think the Earth's core is a natural reactor? 

Evidence that the largest uranium deposit in Canada can't be mined because its a "low level reactor"?

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#34 2012-05-26 06:37:12

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

I still think that a 2 step approach is needed by using solar and nuclear power to create pulsed fields not only in orbit but also at the surface by creating a grid of smaller fields.....

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#35 2012-05-27 02:37:23

karov
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From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Artificial Magnetosphere - Electromagnetic Induction

do we really need to activate the interior liquid phase "dynamo"?

I think planetary scale https://www.google.bg/search?aq=f&sourc … propulsion  is more than enough.

The terraformed body has atmosphere which is ready bubble ( plasmoid http://en.wikipedia.org/wiki/Plasmoid ) material.

The plasmoid magnetosphere could be powered by captured solar wind. ( "just" face one or more of the "poles" of the plasmoid configuration into direction of the source of solar wind ... )

The conductor ring for capturing the solar wind energy for maintenance of the plasmoid magnetosphere could be made of smart http://en.wikipedia.org/wiki/Dusty_plasma.

The dusty plasma ring could be used for light and in general EM optimization of the planetary environment of question, too. ( like the giant reflecting lenses of paulbirch.net ).

AND if the underbody is too small the whole plasmoid complex could work as giant http://en.wikipedia.org/wiki/Plasma_window for atmospheric retention, etc.

It could manage not only nano- and microscopic objects ( iones, molecules and dusticles ), but also bigger ones like in- and out-going shipping traffic ( "geo"magnetic levitation -- http://settlement.arc.nasa.gov/Nowicki/SPBI133.HTM )

If I'm allowed to use such analogy -- one does not need an active volcano around for home heating, far more efficient and safe methods are available.

... and all of them although seeming fragile, are in fact more eternal than the heavy geologcal machinery ones, due to their intrinsic positive feedback-ness.

They use as energy and mass source and manage well exactly these forces which usually are destructive.

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#36 2012-05-29 21:22:34

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Artificial Magnetosphere - Electromagnetic Induction

I like where this is going.  I guess I don't care how the capture mechanism for energy works.  I prefer the capture of solar wind energy, simply because that is what rips the atmosphere of Mars, and conquering it first just feels good.

Then indeed if I have a marginal understanding of your proposals, some utilization of the captured energy to produce sufficient blockage of the worst damage the solar wind can do, making it worthwhile to add atmospheric components.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#37 2012-05-30 18:41:55

SpaceNut
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#38 2012-07-01 09:56:23

SpaceNut
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Re: Artificial Magnetosphere - Electromagnetic Induction

http://science.nasa.gov/science-news/sc … enportals/

"We call them X-points or electron diffusion regions," explains plasma physicist Jack Scudder of the University of Iowa.  "They're places where the magnetic field of Earth connects to the magnetic field of the Sun, creating an uninterrupted path leading from our own planet to the sun's atmosphere 93 million miles away."

Observations by NASA's THEMIS spacecraft and Europe's Cluster probes suggest that these magnetic portals open and close dozens of times each day.  They're typically located a few tens of thousands of kilometers from Earth where the geomagnetic field meets the onrushing solar wind.  Most portals are small and short-lived; others are yawning, vast, and sustained.  Tons of energetic particles can flow through the openings, heating Earth's upper atmosphere, sparking geomagnetic storms, and igniting bright polar auroras.

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#39 2012-07-02 03:04:33

karov
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From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Artificial Magnetosphere - Electromagnetic Induction

SpaceNut wrote:

http://science.nasa.gov/science-news/sc … enportals/

"We call them X-points or electron diffusion regions," explains plasma physicist Jack Scudder of the University of Iowa.  "They're places where the magnetic field of Earth connects to the magnetic field of the Sun, creating an uninterrupted path leading from our own planet to the sun's atmosphere 93 million miles away."

Observations by NASA's THEMIS spacecraft and Europe's Cluster probes suggest that these magnetic portals open and close dozens of times each day.  They're typically located a few tens of thousands of kilometers from Earth where the geomagnetic field meets the onrushing solar wind.  Most portals are small and short-lived; others are yawning, vast, and sustained.  Tons of energetic particles can flow through the openings, heating Earth's upper atmosphere, sparking geomagnetic storms, and igniting bright polar auroras.


Energy extraction? These power-lines sound a bit like the A.Bolonkin's "plasma cord" plasmoid "cables"...

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#40 2012-07-16 01:24:08

orionblade
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From: Hampton Virginia
Registered: 2003-01-14
Posts: 60

Re: Artificial Magnetosphere - Electromagnetic Induction

I have done some back of the envelope calculations on this very topic recently, and I will post merely the results - if anyone's interested in seeing the actual calculations, I don't mind scanning and posting an image of my notes at some point.

In any case, I assumed the worst - a single loop of "wire" - the most malleable/ductile superconductor we have currently is niobium-tin, or in some cases niobium-tin-copper compositions. Assuming this is a single large cable to be unspooled in orbit around Mars, "spun up" as an MRI machine's magnet is powered up, and the whole thing encased in a fairly thin, thermally insulating conduit, and provided with a solar shield around its periphery, this should be able to maintain a low orbit at roughly 200-250Km.

I chose this altitude, versus geostationary, since we want to use the lowest current possible to generate a magnetic field, and the least amount of material possible. Further, the rotational motion of the coil relative to the spin of the planet may add a bit to the effective current, if only a negligible fraction.

My calculations left me somewhat disappointed: For an Earth-equivalent field of roughly 70 gauss, a one-meter diameter niobium-tin alloy superconducting cable, assumed to be solid for purposes of calculation, cooled with liquid helium, would be sufficient, but would require roughly 100% of our annual worldwide niobium mine output for a period of roughly a century, and nearly 10 years worth of Tin production. Taking into account mines that are planned or currently under construction, this could be reduced to roughly 65-70 years. The cost is astronomical, just for materials.

On the bright side, this technique is aided by the damn-near absolute-zero of outer space, so the portion of the cable eclipsed by the planet's shadow should provide enough cooling to allow something as simple as peltier junctions mounted every few meters to counteract any solar irradiation incurred beyond what a properly-spaced reflector could not handle on the day side. Since the whole cable would ride through the shadow every 90 minutes or so, and the solar shield/reflector could be composed of solar panels, the feasibility, if not the initial cost, becomes evident.

Further, the calculations assume that there is absolutely no planet in the middle of the coil. Since Mars has quite a bit of iron through its surface, mantle, and core, presumably, this would become a ferromagnetic core, increasing the field strength. Also, I neglected any plasmadynamic effects. If the field were caused to oscillate, or even held steady, but allowed to gather energy as an electric guitar pickup does, from the moving, time-varying plasma current, one could assume that the power for the coil could be had on-site, and only a minimal current required for start-up, with the current building in opposition to the solar wind, so long as seasonal variations were somewhat sizeable. Depending on the effective permeability of the planet as a magnetic core, the entire thing might well be scaled down by an order of magnitude or two. Further, with vastly superior deflection of electrons than protons, an electron-rich solar wind would allow the induced electric field to do most of the work. Another concept I failed to explore further, mathematically, would call for a non-single-loop coil geometry. Multiple turns wouldn't get you very far, but a helical or interlaced loop geometry could enhance local field strengths such that the aforementioned plasmadynamic effects could yeild a higher electric field strength, and thus better shielding. In any case, any shielding effected would be better than nothing, and the atmosphere should build.


Please consider this one key fact that is often overlooked: Mars' atmosphere is in a state of dynamic stability - it is continually losing atmospheric gas to nonthermal loss mechanisms, yet its atmosphere continues to remain at a stable, if low, pressure and density. If we inhibit even a small fraction of the loss, the atmosphere would build. If on the other hand, we build the atmosphere, we will be losing, perhaps the same percentage, but much more of the atmosphere. We'll be driving the reaction towards loss by adding gas to a lossy system. If we instead reduce loss mechanisms, the gases will add themselves, from whatever surface or subsurface sources are already in operation (anyone notice the detection of subsurface Methane sources not too long ago?). I'll have to look up the effective velocities, and calculate turning angles required for various orbits, perhaps writing up a system of equations and optimizing them for minimum material required (low loop current vs. shorter cable). It may very well be that a geostationary ring would require vastly lower current to achieve an adequate turning angle of maximum solar wind velocity, since it is further from the planet, or it could be that we would be better off with a larger diameter cable much lower in orbit, permitting a larger field but with considerably less cable length to encircle the planet at a lower altitude.

Either way, i would point out that any solution with a multitude of orbital components that are not physically connected, will be subject to magnetic attraction, or at least torques, which would require continual energy input to overcome. I think a single loop, or some variation on this Dyson-like ring is a better bet, since the loop would auto-inflate to a nearly perfect circle under the influence of its own magnetic field, much like a loop of string floating on a soap bubble. Individual magnets would pull together, and multitudes of loops would at the very least rotate to become a toroidal magnetic field, and the gaps between the loops would actually cause a degree of focusing.

It has also occurred to me that a slightly weak magnetic field might result in protection near the tropics, but deposition of solar wind components near the poles - thus heating the poles somewhat, but also adding hydrogen and helium to the atmosphere. Admtitedly, these would boil off rather quickly, but there should be enough radical production that water vapor would be created, and gravitationally retained within the atmosphere... I am uncertain as to the equilibrium state with high incidence angles for stellar wind particles on the atmosphere, if they would eject atmospheric particles more, or if they would be captured at a greater rate than the loss mechanisms... it's an interesting mathematical problem.

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#41 2012-07-16 02:11:41

orionblade
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From: Hampton Virginia
Registered: 2003-01-14
Posts: 60

Re: Artificial Magnetosphere - Electromagnetic Induction

Oh, and another point...

The magnetosphere may only be needed for a while... the artificial one at least.

Think of the planet as your body, for a moment.

The core is powered by nuclear reactions which occur at a relatively constant rate, at least measured over short time spans less than the half-life of the material in question.

If Mars and the Earth are roughly equal in age, and we don't expect the Earth's core to freeze out to nonproductive (magnetically, at least) levels for a billion years or so, then given Mars's 70-ish % surface area compared to Earth, we should expect about 70% of the core life span, given the same radiative cooling apparatus, and roughly equivalent deposition of radioactive elements. Just give-or-take, so Mars should have a geologically active core/mantle. The problem is, it doesn't seem to.

Now, think again of Mars as your naked body. Your core is fueled largely by glucose, but we can neglect that for the moment, and on a small timescale, give you a meal's worth of energy, just as Mars has a formation's worth of radioisotope/thermal energy.

We put you naked into the desert. You are rather warm. You burn very few calories and your core temperature begins, very gradually, to rise. Your energy is largely coming from solar radiation, so your body does not need to burn its calories to maintain heat, but only for motion and brain function. Nontheless, it burns more than it needs for heat, and thus you must sweat to cool off... Mars can't do this, so it would just heat up if we moved it in, to say Venus' orbit. Venus is rather warm, as well.

If we instead, put you out in the middle of the arctic, you would freeze to death in a matter of minutes to perhaps an hour. You are naked. There is no insulation between you and the cold of your effective outer-space, and thus the dominating factors of your body temperature are your metabolism (equivalent to the decay rate/loading of radioisotopes in Mars' core/mantle) and your surface area (likewise on Mars, though spherical).

If I then give you a parka, and boots, and nice thinsulate undergarments, and shove you out onto the tundra, you will be fine for HOURS. Keep your face covered, please, so your nose will remain intact.

You have the same surface area, the same calories to burn at roughly the same rate, but you have insulation which slows the escape of heat from your core to the space beyond your body.

Likewise with Earth. We have an atmosphere. It traps sunlight/infrared radiation, keeping the surface warm, which slows the rate of heat flow between the core and the surface. Temperature differential is where it's at. If you've got two articles that are close in temperature, in physical contact, then heat flows slowly. If one is ice cold and the other is near molten, then the heat flow is rapid. The Sun may not have enough energy to actually melt the core, but it does have enough energy to warm the surface of our planet to an average of 72 degrees. This may be just enough, or plenty enough for the Earth to maintain an active core. If the Sun were flicked off, however, then in a matter of hours, our atmosphere would fall as a layer of oxygen and nitrogen snow, no matter if the core kept molten or not.

I think Mars lost its atmosphere and froze to death.

The large impact basin directly opposite the elevated plateau where Olympus Mons and her sisters reside, the semi-equatorial cliff, the vast lava plains... i think a large impactor disturbed the atmosphere, jacked up convection currents, and before everything got established again, the core cooled too quickly, since Mars' surface area to volume ratio is higher than Earth's. (Smaller diameter spheres have more surface area for their volume, it's the whole pi*r^2 vs pi*r^3 thing, with all those constants thrown in, the volume grows way faster than the surface area, so the ratio of the two also grows with increasing r...) So, it lost its heat very quickly when the atmosphere was disturbed, and then stripped by the solar wind. This would explain why there is little or no nitrogen. Carbon and Oxygen exist in solid form all over the place. just about every rock is an oxide of something, and there are plenty of carbonates and carbonaceous meteorites. Nitrogen, however, only exists as ridiculously unstable solids, as nitrates, which are explosive or ridiculously combustible. You would not expect primordial nitrates to stick around on a hot protoplanetary surface, or even subsurface. They would decompose into oxygen and nitrogen, and if there were no magnetic field, the nitrogen would be stripped off as a gas. Later, when a magnetic field re-established itself, you would be able to build an oxygen/carbon dioxide atmosphere, but you would have no nitrogen reservoir from which to pull.

Someone stole Mars' parka, and all its nitrogen was in the pockets.

So, we can walk around on a terraformed mars (using only the artificial magnetosphere), but we will not be able to grow plants (no nitrogen) and we won't be able to light a campfire (no woody plants to burn) without spontaneously combusting everything around us (no buffer gas... 100% oxygen + 2-300ppm CO2... *POOF*). So we must find an appropriate buffer gas. As far as I can see, given Mars' low gravity, our only options are Nitrogen, Argon, or CO2 itself, which would be rough since we can't breathe high concentrations of CO2... and you'd need at least 20-30% non-oxygen gas to keep the whole place from being positively explosive. I mean, forget trying to repair your spacecraft with any kind of welding equipment - as soon as you got hot enough to weld, the atmospheric oxygen above 90-ish% concentration would start a self-sustaining burn on virtually any kind of steel or aluminum you were working on... kerpoof, there goes the neighborhood.

Just something else to ponder... if we warm the atmosphere, is there enough radioactive material in the core to re-heat and re-melt it, and get the dynamo going again... it should self-start, if molten, just due to momentum and convection... then god forbid, we'd have plate tectonics again, and future Martians wouldn't be relegated to living on a nearly spherical dune-swept marble, but a dynamic, mountain-range-building, living planet. Can you imagine what Himalayan mountains would be on Mars? Equal thermodynamic forces acting opposed to 1/3 the gravity... Mountains that reach to the sky!

*breathes*.

I shall sleep now.

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#42 2012-07-16 04:54:47

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 3,172
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Re: Artificial Magnetosphere - Electromagnetic Induction

You mean like Olympus Mons?

Re. a buffer gas, take a look at the Minimal Martian terraformed atmospheres thread. Midoshi's done a lot of posts there (though a lot are missing after the Great Crash). It seems like CO2 toxicity isn't the problem we thought it was, since Sheep have managed to adapt to 120mb pCO2, and I think humans have adapted 60mb pCO2. Given how we transport CO2 in the blood, I wouldn't be surprised if the upper limit was much higher than this. I'd still like to see the effects on developing fetuses, though. It would seem to be a relatively simple and cheap experiment that would yield valuable information; perhaps one of the space colonisation groups could fund it.

Also, there's at least some nitrates on Mars... Possibly enough for Nitrogen to exist as a significant trace gas. We might have to genetically engineer the plants.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#43 2012-07-16 05:12:07

Impaler
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From: South Hill, Virginia
Registered: 2012-05-14
Posts: 286

Re: Artificial Magnetosphere - Electromagnetic Induction

Let me bring some better Geologic knowledge to bear here.

Yes surface area to volume ratio is a BIG part of why a small planet would cool off faster.  But most of the rest of your speculation is way off base.

First the surface temperatures of the two planets while very different from our biological needs doesn't amount to squat (~ 50K) when compared to the heat of the interior (thousands of degrees K) and no significant difference in cooling rate would be expected from this.  I don't even think Venuses 700 K atmosphere acts to slow the rate of heat loss from the solid portion of the Planet.  The atmosphere no matter how thick or hot is in thermal contact with the surface and just forms a part of the overall thermal gradient between the core and space ware ultimately the heat is being lost and solar radiation received.  What matters is if the material is a good insulator and compared to rock an atmosphere is terrible because it convects.  In fact if the Earth didn't have convection of rock in its Interior the heat of the core would still be at practically the same temperature today billions of years later.  In considering the cooling of ANY planet the convection/conduction ratio will dominate and we don't know enough to characterize Mars cooling other then to say that it looks to have cooled more then Earth.

Second the assumption that Mars would have the same endowment of Radioactive elements per unit volume is way off, Mars is very very low in Density (Mars 3.94 vs Earth 5.51) indicating a lower metal content which would reasonably lead to a lower endowment of Radioactive elements and less heating.  In fact Mars density is so RADICALLY LOW when compared to the very similar densities of the other inner planets that is indicates their was something significantly different about Mars from the very start.

Third, its been know for more then a hundred years the the heat of gravitational collapse was a the principle initial heat source for the accreting Earth, Mars would also have been heated in this way but being a shallower gravity well it would have been heated less per unit of mass.  As each in-falling bit of matter is accelerated faster and faster to impact with the already accreted matter the heating logically gets more efficient.  This explains why small asteroids are completely undifferentiated.  Some of the recent talk about 'nuclear reactors' is a bit over-hyped to the general public.  We have know since the discover of Radium that Radiation was making SOME contribution, but the radioactive elements are most definitely NOT in the core.  While Thorium and Uranium are heavy atoms they form light Mineral and would thus be part of the crust and Mantle, but it should make little difference ware internal the heat is generated.  I've heard numbers in range of 20/80 collapse/radiation as the total cumulative heating budget.  It's possible that Mars didn't get hot enough after accretion for it to differentiate to the same degree as the Earth and it lacks a Magnetic field not because of an over-solidified core but rather from an and under-melted one.  We just don't know.

So basically nothing that we do to the surface will affect the Martian core on Geologic time scales, if at all.

Last edited by Impaler (2012-07-16 05:27:46)

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#44 2012-07-16 11:55:19

orionblade
Member
From: Hampton Virginia
Registered: 2003-01-14
Posts: 60

Re: Artificial Magnetosphere - Electromagnetic Induction

Hmm.

Ok, first, Nitrogen. We BATHE in it here. I think we'll need a bit more than trace amounts for a successful nitrogen cycle on Mars. Just my thoughts. Or, as mentioned, acclimatization or genetic engineering to handle the different gas ratios. Who knows, maybe some latent adaptation from early Earth will come to bear in the otherwise silent genetic code of terrestrial plants when transported to the new environment.

I'll poke around the other thread on buffer gases before I prattle on about Nitrogen again, thanks for the link.

As far as the core temperature, I have two chief points to address. I'm making this quick, as I've been outside mending a fence for my chickens, and I'm terribly hot and uncomfortable, so please don't take a short/terse post as any sort of argumentative tone, I'm simply sticking to my chair at the moment, and that may color my responses. Ick.

So, the first point is the cooling time of a planet from formation. I am on a slow connection, but IIRC, Lord Kelvin calculated the age of the earth to be somewhere in the 5-10,000 year range, based on the surface area to volume ratio of Earth (at that time known fairly well) and he was, from what I recall, within an order of magnitude on all his calculations. So let's be terribly generous and call it 100,000 years. Earth's core should have cooled and solidified a billion years ago, then, if there is no process heating things up inside.

Nonradioisotopic mechanisms available are tidal heating, magnetospheric interaction with the Sun, and impactors. either way, it's been more than 100,000 years since the last impact large enough to liquefy any significant fraction of the planet, and all three of these processes would affect Earth's orbit. The Moon seems a possible candidate for the tidal option, which would not alter Earth's orbit appreciably, but would have circularized and tidally-locked the Moon. Oh wait. The moon is tidally-locked.

Did that happen more than 100,000 years ago? I think, quite likely, it did.

So we are left with, as far as I know, either a magically self-sustaining magnetic dynamo, which would violate conservation of energy (since Earth's orbit isn't perpetually decaying toward the Sun at an appreciable rate) or, radioisotopes in the core/mantle.

I'm not sure why one would assume that the core had no radioisotopes in it. These isotopes are all heavier than, and generally soluble in, liquid iron. We need not have a significant loading of radioisotopes to add heat to the system and keep it molten, but it must be present. I tend to think even if they were all segregated somehow to the mantle, then you might just have enough to melt the outer core and keep it fluid. Just barely.

Now, this brings us to the thermal gradient. As we drill down in the earth, past the first few feet of soil, the temperature of the Earth increases at a few tens of degrees per thousand or so feet, as I believe was posted earlier.

Think of it this way, we have what amounts to a light bulb, providing relatively constant illumination to a sphere of material of known transparency. As the thickness of the sphere is increased, the illumination at the surface of the sphere falls off with the inverse square of the radius of the sphere. By the time you reach the surface, the temperature differential between, say, 100 feet down, and 1000 feet down, isn't terribly high. Tens of degrees. The heat flowing out of the body is spread out over a rapidly increasing surface area as you get away from the core, or even the mantle. This temperature gradient is exactly what you'd expect to see if there were something hot in the center of a body, radiating outward, just as the light bulb. The heat gets "dimmer" as you move outward, since the total heat input is the same, give or take, for each increment we examine, but the surface area explodes as the square of the radius. We're a couple of thousand miles from the core, standing here on the surface. Think of a bonfire. Stand next to it and you're likely to singe your eyebrows. Stand 100 feet away, and you're likely to barely feel its warmth. Wrap it in concrete, and the difference is even more substantial.

Think then, as well, of a furnace in a home. My oil furnace burns at a couple of thousand degrees, yet the outer shell rarely gets over 80 degrees farenheit. Admittedly there's a bit of a cooling system involved, carrying hot water to the rest of my house, but the thermal mass concept is the same - even with the circulation pump shut off, the inside surface of the furnace may be upwards of 600 degrees farenheit, but the outer surface will never exceed 80 or 90 degrees. Why? Because the fire box is only about a foot by a foot square by a foot and a half deep. The outside of the furnace is a full 5 feet long, three feet wide, and four feet tall. (Yes, this is ridiculously large, my house was built in 1957, but that's beside the point)

So all the heat of the core has to leave through the surface. If a planet is light, and not terribly dense, as Mars is, and we can assume it had some sort of geological activity in the past, then one must ask, where did it go? I posit that simply it was on a knife-edge, in terms of equilibrium. It got just enough radioactive elements to keep it hot for just long enough, and either we've witnessed the end of its geologic age due to radioactive depletion, or it's got round about as much hot rock as it had prior to a cataclysm, but it has lost just enough insulation to let it freeze up, its heat rejection outstripping its heat generation by some factor sufficient to cool it in the time since the cataclysm until now, or at least a few hundred thousand to a few million years ago, based on crater evidence @ Olympus Mons, etc.

So the atmosphere can in fact provide a substantial insulation for a molten core tucked away thousands of miles deep. The sun, or any surface activity really, won't have much effect on the core temperature - you're not going to shine a flashlight on an aluminum can and melt it any time soon - but a small heat source, properly insulated, can last a very, very, very long time.

Also, keep in mind that the subsurface temperature within 10-12 feet of the surface of Earth stays at a relatively constant 55-60 degrees in most places. Our average air temperature is slightly higher.

I am a blacksmith in my spare time, and I should also mention that, a properly insulated knife blade, or really any piece of metal I'm annealing, can go into my bucket of perlite or dry kitty litter glowing orange-hot, and many many hours later, still be hot enough to burn you, while the outside of the container isn't even warm to the touch. Direct physical contact, but decent insulation results in a very slow cooling time. I've thought for a long time about mounting a hot metal rod in a thermos bottle and seeing how long it takes to cool down from ~2000 degrees, what with the vacuum insulation and vapor-deposited aluminum mirror surface keeping things toasty.

The question is, what's the cool down time, and what's the actual rate at which heat from the core leaves the surface, and what energy input is needed. Then we can see if the possible radioisotopes dropped on Mars are sufficient to sustain this requisite energy output without undergoing an actual chain reaction, and then see how close we are when we factor in the insulating blanket of a nice, warm atmosphere. I dare say that if the numbers come up close, then we must assume that Mars had a dense atmosphere in the past, and its loss is what drove the core freezing event.

If it is not even close, on the short side, then we can assume that Olympus Mons and its siblings were catastrophic volcanic events resulting from a somewhat molten core and a large impact event, leading to a short-term melt/volcanism event.

But, that's just what I've come up with after some back-of-the-envelope calculations. Anyone wishing to chip in and do some of these calculations and beat me to it, feel free. I'm curious to know how far off my own estimates are.

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#45 2012-07-16 15:47:16

Terraformer
Member
From: Lancashire
Registered: 2007-08-27
Posts: 3,172
Website

Re: Artificial Magnetosphere - Electromagnetic Induction

Re. pre- and neonatal CO2 toxicity, I found this post by Midoshi, which seems to indicate that we could get away with 80mb pCO2 for a final atmosphere.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#46 2012-07-16 23:15:19

orionblade
Member
From: Hampton Virginia
Registered: 2003-01-14
Posts: 60

Re: Artificial Magnetosphere - Electromagnetic Induction

This thread:

http://newmars.com/forums/viewtopic.php?id=6052

made me think...

Why not try for an artificial magnetosphere on the Moon, to limit charged particle interactions with the surface/habs/inhabitants? With a significantly smaller radius, and with the benefit of Earth nearby, it may be possible to generate a pretty decent magnetic field with orders-of-magnitude less cable, and WAY cheaper launch costs... and then we'd have a working model to tool around with. The LHC seems like a pretty decent equivalent budget target...

Thoughts?

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#47 2012-09-23 22:01:44

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,455

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#48 2013-12-08 22:22:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,455

Re: Artificial Magnetosphere - Electromagnetic Induction

UNH Research Helps Unravel Mysteries of Earth’s Radiation Belts

rfi-8819_360.jpg


http://phys.org/news/2013-12-mysteries- … d-van.html

high-energy particles populating the radiation belts can be accelerated to nearly the speed of light in conjunction with ultra-low frequency electromagnetic waves

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#49 2014-05-26 19:06:43

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,455

Re: Artificial Magnetosphere - Electromagnetic Induction

Lower mantle chemistry breakthrough

The lower mantle comprises 55 percent of the planet by volume and extends from 670 and 2900 kilometers  in depth, as defined by the so-called transition zone (top) and the core-mantle boundary (below). Pressures in the lower mantle start at 237,000 times  atmospheric pressure (24 gigapascals) and reach 1.3 million times atmospheric pressure (136 gigapascals) at the core-mantle boundary.

The prevailing theory has been that the majority of the lower mantle is made up of a single ferromagnesian
silicate mineral, commonly called perovskite (Mg,Fe)SiO3) defined through its chemistry and structure. It was thought that perovskite didn't change structure over the enormous range of pressures and  temperatures spanning the lower mantle.

Recent experiments that simulate the conditions of the lower mantle using laser-heated diamond anvil cells, at pressures between 938,000 and 997,000 times atmospheric pressure (95 and 101 gigapascals) and temperatures between 3,500 and 3,860 degrees Fahrenheit (2,200 and 2,400 Kelvin), now reveal that iron bearing perovskite is, in fact, unstable in the lower mantle.

The team finds that the mineral disassociates into two phases one a magnesium silicate perovskite missing iron, which is represented by the Fe portion of the chemical formula, and a new mineral, that is iron-rich and hexagonal in structure, called the H-phase.

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#50 2014-08-17 15:00:32

knightdepaix
Member
Registered: 2014-07-07
Posts: 225

Re: Artificial Magnetosphere - Electromagnetic Induction

I know that the following is a very wild idea.

After reading about solar wind and planetary rings on this website, is it feasible to create multiple planetary rings above mars that composed of regolith and "dancing around" the planet near or in artificially thickening atmosphere of CO2 and perfluorinated carbons(PFC)? My ideas are instead of BLOCKING solar wind radiation with artificial magnetosphere and thickening the Martian atmosphere, why not exploiting solar wind's chemical composition to make nitrogen for terraforming use and heat up the planet.

About "dancing around", like the dancing ribbons in Ribbon dance, could each of the rings be artificially made to tidally locked in orbits so their orbits remain synchronically stable or move around the planet in duration. At any given time, the orbits of the rings at different heights would absorb or deflect energetic atoms of solar wind, any gaseous molecules at temperature of the Martian CO2 atmosphere and energy are dissipated in contributing to heating up the planet.

For traveling onto and out of the planet, spaceship could travel in curved paths through the gaps of the rings at different heights while charged particles of solar wind plasmas can only go straight, except deflected or bent by magnetosphere, which in essence does not exist.

Schematic chemical equations:
Incoming solar wind would detach/reduce/interact with CO2 to produce C and O
CO2 + hv ---> C-12 + 2O
Regolith in these rings is then interacted to produce neutron radiation that together with the protons in solar wind fuse with the detached carbon to make nitrogen ?
C-12 + n + p ---> N-14 + energy
Hydrogen forms water with detached oxygen
2p + O ---> H2O + energy

Heavier chemical elements are attached to regolith in element or as fluorides after interacting with PFCs.

Some past discussions:
http://www.newmars.com/forums/viewtopic.php?id=6824
http://www.newmars.com/forums/viewtopic.php?id=7069
http://www.newmars.com/forums/viewtopic.php?pid=117924
http://www.newmars.com/forums/viewtopic.php?pid=119898

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