Magnets are everywhere, and almost all mechanical and electronic equipment use magnetic accessories. Therefore, the magnetic field has long become an integral part of the modern world. In nature, the most easily attracted material by magnetic field is naturally “iron”. However, anyone with a little medical knowledge also knows that the human body contains iron, especially in the blood. This leads to some questions. For example, if the human body is often exposed to the magnetic field every day, will the iron in the blood be absorbed by the magnetic field? Will magnetic field damage people’s health?
Even, will a particularly strong magnetic field bring life danger to people?
Interesting experiment
In order to study these problems, scientists have done a group of interesting experiments, but the experimental results are somewhat surprising.
In the first experiment, scientists used water and plastic tubes added with red pigment to inject red water from the upper end of the plastic tube and flow out from the lower end to make the red water flow to simulate the blood flowing in human blood vessels. Next to the plastic tube, scientists placed magnets to observe the effect of the magnetic field on the simulated “blood vessels”. The results show that when the red water does not contain iron, the magnetic field will not have any effect on its flow; However, if iron filings are added to the red water, when passing through the magnetic field, the iron filings in the plastic pipe will gather near the magnet to form an embolism and block the “blood vessels”.
Obviously, if the human body contains iron filings, the magnetic field will block the blood vessels of the human body and endanger life. Fortunately, however, the iron in our blood is not the elemental iron in the form of iron filings, but a part of hemoglobin, which is responsible for the red color of the blood, transporting oxygen from the lungs to human cells and taking away the carbon dioxide produced by the cells.
How much iron does hemoglobin contain? Structurally speaking, hemoglobin is a very complex macromolecule. A simple comparison can be made. The content of water in blood is about 50%, and a water molecule is only composed of two hydrogen atoms and one oxygen atom. Hemoglobin is different. Its molecules are composed of 2952 carbon atoms, 4664 hydrogen atoms, 832 oxygen atoms, 812 nitrogen atoms, 8 sulfur atoms and 4 iron atoms.
There are only four iron atoms? yes. It can be seen that the content of iron in human blood is not very much. The blood will not react to the general intensity of magnetic field. So the scientists carefully designed the second experiment. Instead of human blood, they use thick pig blood to put them in light foam plastic containers, then float the plastic containers floating on the still water surface, and then use giant magnets with super strong magnetic force to approach containers. Because foam plastics float on a smooth surface without friction, even if it is subjected to weak magnetic force, it will drift on the water surface. What will be the result of the experiment? Contrary to people’s expectations, pig blood and magnet are mutually exclusive.
Why is blood diamagnetic?
Blood and magnets repel each other. Scientists call this phenomenon “diamagnetic reaction”. Since human blood contains iron, why is blood diamagnetic? In fact, magnetism is closely related to the structure of atoms.
Simply put, magnetism comes from the movement of electric charges. That is why electrified conductors (such as solenoids) can produce magnetic fields. In atoms, electrons can generate micro magnetic fields through spin motion. Although protons and neutrons in atomic nuclei also have their own magnetic fields, they are much weaker than the magnetic fields generated by electrons. On the whole, the magnetic field of an atom will be determined by the magnetic field of electrons. According to quantum mechanics, the electrons in atoms exist in the form of “pairing”. The paired electrons will have opposite spins, which will offset each other’s magnetic field. A net magnetic field is shown only when there are unpaired electrons in the atomic or crystal structure. Therefore, scientists can determine the magnetic reaction by calculating the number of unpaired electrons in a substance.
Taking elemental iron as an example, the outermost layer of each iron atom in iron filings has four unpaired electrons, which will make a single iron atom show strong magnetism. Under the action of the external magnetic field, the direction of the magnetic field of a single iron atom “obeys” the direction of the external magnetic field, so the iron atom has paramagnetism.
For hemoglobin, the situation is much more complicated. Scientists have found that the number of unpaired electrons in iron atoms in hemoglobin depends on the oxidation degree of hemoglobin. For example, each iron atom in deoxyhemoglobin (that is, hemoglobin without oxygen) has four unpaired electrons, which makes deoxyhemoglobin have weak Paramagnetism; The oxygen atoms in hemoglobin (that is, the oxygen atoms in hemoglobin) are not paired with iron, so that hemoglobin has no anti magnetism. Oxygenated hemoglobin accounts for more than 96% in arterial blood and 60% to 80% in venous blood. It can be seen that most hemoglobin in the blood is diamagnetic, and the water that constitutes half of the component is also diamagnetic. Therefore, although hemoglobin contains iron, blood is repulsive to magnetic field.
Safe daily magnetic field
Whether paramagnetic or diamagnetic, magnetic field has an effect on blood. But don’t worry, because the magnetic field that human beings are exposed to in daily life is very weak, which is not enough to affect human health.
We know that in physics, the unit used to measure the magnetic field strength is called Gauss, and the larger unit is Tesla. 1 Tesla is equivalent to 10000 Gauss. The magnetic field intensity on the earth’s surface is only 0.25 to 6.6 Gauss, which can only affect pigeons and help them find their way home. The magnet used in the refrigerator is about 50 Gauss, and the electric guitar pickup is about 100 Gauss.
The most powerful magnetic field that ordinary people have access to is the magnetic resonance imaging (MRI) technology occasionally used in physical examination or medical treatment. Nuclear magnetic resonance scanners use superconducting magnets, which can produce a strong magnetic field of 15000 to 94000 Gauss. A magnetic field of this magnitude can cause the only proton in the nucleus of a hydrogen atom to vibrate, causing the latter to emit radio waves that can be read by the instrument. For ordinary people, MRI is safe. Unless you have metal implants in your body, it will cause danger – during MRI, any metal implant will be violently pulled by the magnetic field, causing great damage to you.
What if you eat a lot of iron, or a villain injects you with some iron? Then the iron will be rapidly decomposed in the intestine for absorption by the human body, and then become very dispersed, so that the iron content remains low. For example, iron in cereal can even remain ferromagnetic, but even if it is still in your stomach, it will not be vibrated by the magnetic field of the MRI instrument. Therefore, if you ingest or inject enough iron, you should be more alert to metal poisoning than worrying about the magnetic field.
Scary magnetic star
Is a magnetic field strong enough to kill you? The answer is yes. But you have to go on star trek to see the power of this magnetic field.
In the vast space, when the mass of a large star is 1.5 to 3 times that of the sun, it will experience a war between nuclear fusion and gravity. In the end, gravity will win. After a huge explosion called supernova, all matter will be tightly bound by gravity, so that most electrons will be pulled into protons and combined to form neutrons to form a celestial body called neutron star. Neutron stars are more massive than the sun and have an astonishing density – a teaspoon of neutron stars will have a mass of more than 1 billion tons. Neutron stars usually rotate at hundreds of revolutions per second. Protons and electrons form an electric current around the fast rotating neutron star, producing a powerful magnetic field of trillions of Gauss. This is enough to disrupt the chemical reactions and synapses that occur in your body and take your life.
Finally, let’s talk about a very interesting celestial body – magnetic star. About one tenth of neutron stars have enough surface current and spin speed to have a magnetic field of up to 4 trillion Gauss. Such neutron stars are magnetic stars. The nearest magnetic star to the earth is called “axp1e 1048-59”, which is about 9000 light-years away from the earth. If you are close enough to it, for example, hundreds of kilometers – assuming you are not killed by cosmic rays at this time, the strong magnetic field generated by this magnetic star will pull out the electrons in your body, then destroy the molecular bonds in the cell and pull your atoms away one by one, and you will turn into a wisp of “green smoke” and fly spirally to this super massive magnetic star, Eventually become a part of it.
Therefore, on earth, humans will not be harmed by the magnetic field, but if we want to explore space, in addition to cosmic rays and vacuum, humans also need to be vigilant against the threat of the magnetic field.
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