Why isn’t iron pulled down to the Earth? Would magnetic materials like iron be lighter or a planet without a magnetic field?

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Why isn’t iron pulled down to the Earth? Would magnetic materials like iron be lighter or a planet without a magnetic field?

In: Physics

Earth’s magnetic field isn’t powerful enough to actually move anything with much mass.

That said, iron is denser than rock and it is pulled down into the earth by gravity. When the earth was forming and still completely molten nearly all the metal *did* sink to the center. Metal deposits we find closer to the surface were deposited later by asteroid impacts or volcanic activity.

Well, to begin, it’s worth mentioning that Earth’s magnetic field is extremely weak, so any force it applies would also be very weak.

Next, iron isn’t magnetic on its own. It has to be magnetized. In natural iron, this can be done by Earth’s magnetic field, but that resulting magnetization is also extremely weak.

Now, we can think about what forces the iron experiences. Think about it this way, if you’re looking at a compass, does either end of the needle get pulled down? It doesn’t. Instead, it aligns itself with the magnetic field. That’s because magnetic fields are shaped differently than other force fields (Google “magnetic field lines” to see the shape). They don’t just push or pull from the center, they have two poles and the field lines curve out between these poles.

When iron is magnetized in the crust, it’s already aligned to the magnetic field because that’s what magnetized it. It is then pulled slightly harder toward the pole it’s closer to, but not so much that it really affects anything. Earth’s gravity is far, far stronger than its magnetic field.

In summary, Earth’s magnetic field wouldn’t pull the iron down so much as toward the closer magnetic pole. However, this force is very, very weak compared to Earth’s gravity so it has no effect.