Magnets are everywhere. Just about every electronic device uses them including the speakers you’re using to listen to me talk right now. Deriving their name from the Greek Island of Magnesia, magnets have come to play an integral part of our modern world.

As anyone whose ever watched a certain particularly powerful mutant of the villainous variety do his thing knows, the human body contains iron. This iron serves many purposes including allowing oxygen to hitch a ride from the lungs to the rest of the body via the bloodstream.

Since we’re exposed to magnets on a regular basis every day and magnets attract iron, this brings us to the question- Could the iron in your blood be removed with an especially strong magnet or by a certain mutant with a magnetic personality? And regardless of the answer to that, is it possible to make a magnet strong enough to simply kill you on the spot? And how would this happen? And just what are the most powerful magnets in the universe?

Before we get to all that, it’s important to understand why magnets effect iron in the first place.

Iron exhibits a property called ferromagnetism because the four unpaired electrons in the outer shell of each atom have the quantum configuration to give it a strong magnetic field and make the iron atoms act like microscopic magnets. The poles of these magnetic atoms will align with an outside magnet creating an attractive force since the opposite poles are attracted and facing one another. The protons and neutrons in the nucleus of the atom also have their own magnetic fields, but they’re much weaker than what’s created by the electrons and don’t have any significant effect on the overall magnetic field of the atom.
Iron also has domains, which are about a millimeter across and consist of magnetically aligned atoms. If a strong enough magnetic field is applied, the magnetic fields of all the iron atoms in all the domains will also align. If a magnetic field is applied for long enough, the domains in the iron will remain aligned even after the magnet is gone causing the iron to become magnetized creating a permanent magnet. There are also some other metals that exhibit this ferromagnetic property including nickel, cobalt, and gadolinium as well as certain alloys or mixtures of metals and can be made into permanent magnets. You may have a few on your refrigerator.

So that’s why the two love to tango, now let’s talk about potentially ultra strong magnets that may or may not be capable of ripping iron from your blood or killing you in other ways. Enter electromagnets

A magnetic field is created when an electric charge accelerates. You might also have created an electromagnet in school by coiling a wire around a nail and attaching the ends of the wire to a battery. The current supplied by the battery is spiraling around the nail through the wire creates a magnetic field, because it’s undergoing a centripetal acceleration.

Magnetic field strength is measured in Gauss. The unit of measurement for 10,000 Gauss is called a Tesla (tribute to Nicola Tesla). For reference, the strength of Earth’s magnetic field at the surface is between .25 and .6 Gauss depending on where you are in the world. It’s not very much, but it’s enough to manipulate the needle on a compass and allow a pigeon to find its way home. A typical refrigerator magnet has around 50 Gauss, electric guitar pickups have about 100 Gauss, and an industrial electromagnet that’s used to pick up scrap metal at a landfill will have 10,000 Gauss or one Tesla!

As for Superconducting Magnets, the higher the electric current running through a coil in an electromagnet the stronger the magnetic field will be created. However, the wires that make up the coil may be electrically conductive, but they still have a little bit of resistance meaning that some of the electrical energy from the current running through the wire will be turned into heat. This is what causes the coils in a toaster, oven, or certain lightbulbs to get hot and glow.

To get around the problem, superconductors are used, which are materials that have no electrical resistance but only work at low temperatures. They have to be kept very cold using liquid nitrogen or even colder with liquid helium. Since they have no resistance, they can handle a lot more electrical current without heating up and thus one can create incredibly strong magnetic fields.

This brings us to one of the most powerful magnets mere mortals occasionally encounter in the form of Magnetic Resonance Image (MRI’s). One of the main uses of these superconducting magnets is to image the body in an MRI machine that can produce from 15,000 up to 94,000 Gauss. This immense magnetic field causes the lone protons in the nucleus of hydrogen atoms that are part of the water molecules in the body to precess like the way the needle on a compass shakes when you put a magnet next to it. This precession occurs at a frequency to allow the protons to absorb and transmit radio waves, which can be detected to create a 3-D image if the magnetic field is applied in multiple directions.

So that all out of the way and with your brains sufficiently full of a rather attractive amount of magnetic knowledge, this finally brings us to how much iron is in human blood, and why doesn’t it get sucked out during something like an MRI or similarly insanely powerful magnets?

The average human body contains 3 to 4 grams of iron almost all of which is contained in molecules like hemoglobin. In this hemoglobin, of which there are a few types, the outer electrons of the iron which cause the ferromagnetic properties mentioned earlier are in a different configuration because of the coordinant-covalent bonds with other atoms like nitrogen. These bonds don’t allow the electrons to align with a magnetic field rendering the iron atoms only paramagnetic, which is a very weak attractive property a lot of atoms and molecules have. There’s also only one iron atom per hemoglobin molecule.

Furthermore, some other molecules have a repulsive diamagnetic property including water, of which there is a lot more of than iron in your body. Thus, even a super powerful magnet like in an MRI only has a miniscule effect on the iron if any, which is why it’s safe for you to be inside one.

However, if a you have any metal implants an MRI, it would be quite disastrous. The steel that’s usually used in pins, plates, and any prosthetic body parts contains ferromagnetic iron. These shows up well on x-rays or CAT Scans which are done to check if there’s any concern there could be any metal implants that would get violently ripped out and fly around in multiple directions during an MRI causing extensive damage to the patient, the machinery and anyone else in the room.

But what if you eat a huge amount of iron containing foods or if a shapeshifting mutant injected you with some?

Iron is quickly broken down for use in the body in the small intestine. The iron in cereal is still in elemental form and retains its ferromagnetic properties but won’t cause any of the disastrous effects mentioned even it’s were still in your stomach waiting to be absorbed. It’s just not enough to cause an issue in something like an MRI, and it’s also very thinly dispersed. Further, you would almost definitely get iron poisoning if you ingested or were otherwise injected with enough to cause any ferromagnetic effects before it’s broken down.

On a similar note, Gadolinium is sometimes injected before an MRI to increase the contrast of the tissue that needs to be imaged. Gadolinium is ferromagnetic, which is why it shows up well in an MRI and is used as a contrast dye. However, it’s not enough to cause any issues from the magnetic field.

Now all that said, even though the iron in the human body doesn’t have ferromagnetic properties, there are still some lesser known effects magnets can have in an especially strong enough field.

For example, small animals like frogs and mice can be levitated in very powerful magnetic fields, because when a magnetic field is strong enough, the water and other elements including the iron in their body that aren’t normally magnetic experience the repulsive diamagnetic and attractive paramagnetic forces. These forces are much weaker than the ferromagnetic force that attracts iron, which is why it only becomes apparent with a very powerful magnet like the one at the National High Magnetic Field Laboratory at Florida State University producing more than 100,000 Gauss, which is what it takes to levitate even a small animal in the center of the coil, called the solenoid. Unfortunately, magnets powerful enough and have a solenoid big enough to levitate a human don’t exist on Earth… yet.

This brings us to the question of whether there is a magnet strong enough to actually kill you?

Well… For that we have to go interstellar. When a large star between 1.5 to 3 times the mass of the sun comes to the end of its life, it will go out with a bang. The war between nuclear fusion and gravity comes to an end with gravity ultimately winning. All the particles are pulled towards the center, smashing together in a huge explosion called a Supernova. If there’s not enough mass remaining to form a Black Hole, whatever remaining matter that isn’t scattered about the rest of the universe by this explosion will be bound so tightly from the gravity that most of the electrons get pulled into the protons and combine to form neutrons creating what we call a Neutron Star. It has the mass greater than the sun but the size of a city making it extremely dense, one teaspoon of a Neutron Star would weigh over a billion tons!

Neutron Stars usually also spin very quickly, up to hundreds of revolutions per second, and since not all the protons and electrons combine in a Neutron Star, they can form electric currents around the quickly rotating surface creating a powerful magnetic field reaching up to an insane trillion (1012) Gauss at the surface. This is strong enough to disrupt the chemical reactions and nerve synapses that take place in your body and keep you alive. Thus, it turns out that while it’s not something you really need to worry about in your day to day life, the magnetic field around a Neutron Star is so powerful, it can kill you.

And on that note, before we end today, let’s talk a little about a rather fascinating phenomenon known as Magnetars. If just killing you is not enough- roughly one in ten of these Neutron Stars has enough surface current and spin slow enough to give it an extremely powerful magnetic field of a quadrillion (1015) Gauss. We call this a Magnetar, and the closest one to Earth is AXP 1E 1048-59, approximately 9,000 light years away. If you get close enough to it, say within a few hundred miles, and assuming you could even survive the radiation, this extremely powerful magnetic field created by this Magnetar will pull the electrons in your body causing your atoms to elongate parallel to the extreme magnetic field. It will then destroy the molecular bonds holding you together and rip you apart atom by atom, leaving your remains to get flung out into space or spiral in towards this super massive Magnetar, eventually becoming a part of it.

Which all begs the question, just how powerful is Magneto, and can he rival a Magnetar? If anyone knows the answer, feel free to enlighten us all in the comments below.

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