Why doesn't the moon have magnetic poles like the Earth?

Answer 1

What forms a planet's magnetic field is its spin. This is seen in the planet Venus, whose mass is similar to that of Earth. Venus has very little spin and a very slight magnetic field. Earth having a greater spin has a greater magnetic field.

The reason for a magnetic field forming as it does within a large solar mass is due to the energy of rotation increasing as one moves from either pole toward the equator. What happens as the energy of rotation meets at the plane of our planet's equator , each moving with an opposite spin to that of the opposite hemisphere, is that a strong shearing action is created through this area where a plasma exists. When there is a strong shearing action through a plasma (a state of mass existence where electrons no longer directly associate with individual atoms) a strong electric field is generated. When an electrical field is formed a magnetic one automatically exists at right angles to the electric one. It is for this reason we have opposing poles within our planet - hemisphere energy of rotation (known as the Coriolis Effect) brings it about. The moon has no spin.

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Answer 2

Well, the moon has a megnetic field but, unlike Earth, it's not produced by a dipolar magnetic field. Also, the magnetic field is almost entirely crustal in origin, meaning it's from material in the moon's crust. The Earth, on the other hand, has a geodynamo at it's core which is the reason why we have a two poles. There is a theory that the moon once had a geodynamo as a core, but it has since "died." this theory relies on the fact that lunar magnetizations are somewhat clumped towards opposing poles of the moon.

Answer 3

Hello!
The answer lies in the different compositions of the Earth and Moon. Our home planet is made up of four different layer: crust, mantle, liquid outer core, and solid inner core. The Earth's magnetic field is produced by convection currents in the outer core.

The moon, from what we can tell by seismic recorders left there by astronauts, has a very different structure. Although it also has a crust, a solid iron core, and a mantle-analogue called the lithosphere, the moon's outer core is not fully liquid. It is described as "plastic". This isn't to say that there are huge deposits of Hefty bags in the moon's interior - just that the material there has a higher viscosity (resistance to flow)
than a regular liquid. So the moon's outer core is halfway between a liquid and a solid and it doesn't move around like the Earth's outer core does, so It can't keep up a strong magnetic field. Although the moon did have a magnetic field to begin with (we know this because we've examined the crystal structure in moon rocks), magnetic fields tend to fade over time
unless there is something replenishing them. That process doesn't work on the moon so these days it has no magnetic field.

I hope this helps explain it.
Take Care!

Answer 4

It does have a magnetic field. The poles are weak:

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The Moon has only a very weak external magnetic field in comparison to the Earth. Other major differences are that the Moon does not currently have a dipolar magnetic field (as would be generated by a geodynamo in its core), and the magnetizations that are present are almost entirely crustal in orgin. One hypothesis holds that the crustal magnetizations were acquired early in lunar history when a geodynamo was still operating. The small size of the lunar core, however, is a potential obstacle to this theory. Alternatively, it is possible that on an airless body such as the Moon, transient magnetic fields could be generated during large impact events. In support of this, it has been noted that the largest crustal magnetizations appear to be located near the antipodes of the giant impact basins. It has been proposed that such a phenomenon could result from the free expansion of an impact generated plasma cloud around the Moon in the presence of an ambient magnetic field.[19]
(Source: see below)
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One reason is likely due to the same process that earth is undergoing at the moment, where the poles are weakening and thought to be in the process of reversing. In the middle of the reversal process, the poles would appear to disappear, though there would still be a weak magnetic field.

Answer 5

The magnetic poles on earth are created by the molten core of the planet. And the movement of the this liquid metal. If the center of the earth cooled and became solid then the earth would no longer have the poles and magnetism as we know it. I belive the moon is a dead 'planet' and that it is just a solid, so to speak, mass all the way through, with no molten core.

Answer 6

The moon has no global magnetic field like the Earth because it no longer has an internal dynamo.

Answer 7

the earth's core is hot, spinning and made mostly of metals. this creates magnetism and the poles.
the moon's core has pretty much completely cooled and solidified. it is basically just a rock, activity ceased long ago.

Answer 8

the moon doesn't have magnetic poles because it doesn't have a liquid metal spinning core like the earth

Answer 9

it does! Why not?