Astronomers' magnetism (as described in many books) has very interesting properties. It includes magnetic energy somehow and appears from nowhere. It is claimed to be responsible for the formation of sunspots and operates through magic lines of force.
The second sort of magnetism is different. It seems that some authors of books on astronomy think that electromagnetism and magnetism are the same. Electromagnetism has nothing whatever to do with ordinary (static) magnets. It is a form of stress in spacetime that enables radio and light waves to propogate. It is created by a very rapidly changing combination of electrostatic and magnetic fields. For most practical purposes the slowest rate of change for an electromagnetic wave to propogate effectively is around 5KHz.
The third category is what I know as real magnetism. It is only a property of a flowing electric current. Magnetism produced by an electric current can cause some ferrous materials to become permanently magnetised. For all pratical purposes real magnetism is a static phenomenon. If the current that produces the magnetism varies, the magnetism will vary directly in step with the variations in the electric current. There are no Lines Of Force in a magnetic field. The lack of lines of force applies equally to electrostatic and gravitic fields. A real magnetic field will always deflect a moving charged particle sideways at 90 degrees to the path of the magnetic field.
The Earth's Magnetism.
Because there is a claim that the metallic core of the Earth apparently rotates at a different speed to the rest of the Earth it has been claimed that the differential movements of the metallic parts involved have given rise to a self-sustaining magnetic field. Somehow the existing magnetic field induces currents in these moving metallic parts of the Earth to create the magnetic field that induces the currents in the first place. A fundamental law concerning electricity and magnetism is Lenz's Law. In practice the law can be stated as:
The current induced in a moving conductor in a magnetic field will produce a magnetic field in opposition to the current inducing field.
This law means that there is no way that any moving conductor in a magnetic field can produce a magnetic field with its current that is of the same polarity as the current inducing field. A self-sustaining magnetic field is therefore impossible.
The magnetic field that is observed around the Earth must be created by some means that isn't obvious. It is created like all original magnetic fields by an electric current. The current is caused by the rotation of the Earth, its atmosphere that generally rotates with it, and the solar wind. The solar wind consists of invisible ionised particles that are predominantly positively charged at the moment. The proton density of the solar wind at the Earth's orbit is around 5 per cubic centimetre. The protons dragged around the Earth by the Earth's atmosphere form a positive current. (The currents in wires are made up of electrons and are negative currents. Protons and electrons have equal and opposite electrical charges.) The positive current around the Earth creates a magnetic field that is roughly in line with the Earth's spin axis. Its orientation is such that it creates a south seeking magnetic pole near the Earth's geographic north pole. The south seeking pole attracts the north seeking ends of compass needles. The ordinary navigation compass indicates that there is a south seeking magnetic pole near the Earth's geographic north pole. A south seeking magnetic pole near the north geographic pole can only be created by a proton current flowing around the Earth eastwards,
A current of ionised particles has a property that can be tested with two parallel wires that are close together. If currents in the same direction are passed through the parallel wires, the wires will be attracted to each other. If currents in opposite directions are passed through the wires, the wires will be repelled from each other. The ionised particles that make up the current around the Earth are effectively millions of parallel current carriers. Their individual magnetic fields join together forming one overall field. This causes the particles to be brought very close together in a thin ring around the Earth. As these particles travel around the Earth at the same speed as the atmosphere they are in, there are few if any collisions with the atoms that are in the atmosphere where the ring is located. In consquence, few, if any photons are emitted where the ring is located.
The general shape of the magnetic field around the Earth is similar to that of the skin of an apple. Most apples have a shape where the skin around the middle is furthest from the core. The magnetic field around the Earth at a strength that will deflect ionised particles is furthest from the Earth's centre around the equator. The atmosphere at this level around the Earth is practically absent. The same strength of field is nearer the centre of the Earth near the poles. This is at a level that is well within the Earth's outer atmosphere. Charged particles arriving at the Earth are deflected sideways around the Earth by the north-south orientation of the Earth's magnetic field. Around the equator there is practically no atmosphere for these deflected particles to collide with. At the poles the shape of the Earth's magnetic field is very similar to the skin of an apple around its stalk. Like the apple's skin around its stalk, the magnetic field forms a conical well with its centre at the magnetic pole. The region around the edge of this conical well is where the aurorae are formed. The arriving ionised particles are deflected sideways around this region in a circle. Many of the deflected particles collide with atoms in the atmosphere causing them to give off the photons we see as the aurorae. Down in the conical well the atmosphere is shielded from the arriving charged particles so there is no interaction between charged particles and the atmosphere nearer the Earth's surface. The apple shows the general shape of the magnetic field near the poles and the higher region around the apple stalk roughly corresponds to the position of the aurorae around the poles.
A phenomenon associated with the aurorae is a form of radio signal. It is at the lowest frequency of the electromagnetic spectrum. The frequency is in the audible range below 15KHz. The signals can be received on an audio amplifier whose input is connected to a long wire aerial. The signals are known as "whistlers" because they have a falling whistle-like tone. I have read that these whistlers are caused by charged particles spiralling around magnetic lines of force as they fall towards the Earth. As there are no magnetic lines of force, this explanation for their cause is meaningless. Charged particles could spiral down the conical well shape of the magnetic field at the poles but not anywhere else.
The Sun's Magnetic Fields
It is when astronomers talk and write about the sun's magnetic fields that they seem to make the most ludicrous errors. There is a record of an almost complete misunderstanding of what magnetic fields are like available on the internet. The "Babcock Model" for sunspots proposed by Horace W. Babcock is a case in point. There are no such things as magnetic lines of force or the "field lines" referred to by Babcock. Without the non-existent lines, Babcock's hypothesis falls apart. A magnetic field has some properties that are the same as for a gravitic field. It has no lines and no definable boundaries. It is either stronger or weaker depending on the position where its strength is measured. Nobody has ever detected a step change in strength of a gravity field or a magnetic field. There may be changes of strength at the quantum level but, like most other quantum phenomena, they are extremely hard to detect if they exist. As Babcock's lines don't exist there must be some other explanation for sunspots. I think that sunspots are a product of the sun's vulcanism. I will outline the logic that leads me to this conclusion.
George Ellery Hale was the first person to observe the fact that there are magnetic fields associated with sunspots. He was not aware of a phenomenon that we are very familiar with now. It is the solar wind. The solar wind is a stream of charged particles emitted from the sun. The particles detected near the Earth are predominantly protons. The solar wind can only be detected directly by its electrostatic charge. It can't be detected in the visible and infra red spectra. The solar wind is so transparent that it causes no obstruction to vision even when viewing the sun or stars apparently near the sun during an eclipse. Looking through 93 million miles of the solar wind gives the impression that there is nothing there. But it is there. My first knowledge of the solar wind was obtained indirectly. In 1944 and 1945 I had developed the hobby of building my own radios. I started to get two magazines, Practical Wireless and Wireless World. These two magazines made many references to long range short wave radio reception. The long range reception was explained through reflections by the Heaviside and Appleton ionised layers around the Earth. In the Wireless World there was a feature dealing with the predicted Maximum Usable Frequencies (MUFs) for transmission or reception one could expect during the coming month. The MUFs were higher when sunspots were more numerous. The reflective capabilities of the ionised layers were stronger when there were a lot of sunspots visible. It was later that I learned about the solar wind that varies in strength more or less in proportion to the number of sunspots visible. The ionised layers are now known as the E and F layers.
George Hale could detect the magnetism around sunspots but he could not see the solar wind. We now know that the solar wind is stronger when more sunspots are visible so it must be presumed that sunspots are the source of at least part of the solar wind. We also know what the solar wind consists of. It is made up of ionised particles. In this instance the ionisation is caused by atoms losing electrons. In the case of hydrogen, losing an electron means that the proton is left on its own. The reference books indicate that the density of unneutralised protons in the solar wind at the Earth's orbit is around 5 per cubic centimetre. This fact will have greater relevance later.
Protons have mass. They make up most of the
mass of hydrogen atoms. A proton has 1800 times the mass of an
electron. The protons arriving at the Earth's orbit must have
been launched from the sun by some means. Since the sun's gravity
is 28 times as strong as the Earth's gravity, an enormous amount
of energy must be expended to launch the protons that reach the
Earth in the solar wind. The sun's speed of escape is 386 miles
per second. That means that the protons that leave the sun must
leave at 386 miles per second or more. Something must accelerate
them up to that speed. (Imagine travelling from London to Edinburgh
in one second.)
These facts are what are definitely known. The next part is my hypothesis.
I think that sunspots are eruptions from within the sun's interior. At least, I think that one of each pair of sunspots is the site of an eruption. What is ejected from a sunspot is no more visible than the solar wind because what is ejected is a part of the invisible solar wind. We know that a photon is produced when an electron in an atom falls from a higher energy level to a lower one. If the temperature is high enough to cause atoms to lose their electrons there are fewer electrons available to fall from higher energy levels to lower ones. This means that there are fewer photons emitted where this occurs. As we detect the presence of light and heat by the density of photons, if there are less photons emitted in a region than are emitted in the surrounding area, the region will appear to be dimmer and cooler than its surroundings. This is why I think that sunspots appear to be darker and cooler than the surrounding photosphere. The energy source that creates a sunspot must originate in the part of the sun that is well below the sun's apparent surface. It is many times hotter than the sun's photosphere which is continually cooled by radiation. The extreme heat that launches the protons outward also accounts for the lack of photons. What is launched is a jet of very highly ionised invisible particles.
A stream of ionised particles has similar properties to electrons flowing in a wire. It is an electric current. A property of every electric current is that it always has a magnetic field around itself. The current formed by the jet of particles emitted from a sunspot at 386 miles a second or more will be extremely large. The magnetic field around the jet will also be extremely strong in proportion. The observation of extremely strong magnetic fields at the sun's apparent surface is an indication of the strength and speed of the ejection of invisible ionised particles.
Images of the sun obtained by NASA show that
it is covered in thousands of luminous arcs.
I think that these arcs are of ejections of matter that have their energy sources near to the apparent surface of the sun. The images show brighter regions where the arcs are apparently emitted. These arcs are also apparently made up of ionised matter. They do not spread in the same way as a water jet arc does on Earth. This is because the jets have magnetic fields around them that constrict the ionised matter in a relatively narrow path. The NASA images appear to show that these arcs occur in pairs. I think that the destination point for one arc is at or near the source point for the second of the two arcs. The energy and material from one arc provides some energy and material to sustain the other arc because the pairs of arcs apparently last for several minutes in the moving images I have seen. In most astronomy books I have read these arcs are called magnetic loops. This must be one of the most stupid howlers ever coined by an astronomer. Magnetic fields are always invisible. They are just as invisible as gravity fields.
The next hypothesis is that the jets emitted from sunspots are just very much larger versions of the small visible arcs. The material in a jet emitted from a sunspot is extremely highly ionised The temperature of the ejected material is so high that few photons are emitted along the path of the resulting arc. The arc is invisble against the brightmess of the photosphere. Nevertheless it is an arc of material that returns to the sun's apparent surface. Like the smaller more visible arcs it it constrained in a relatively narrow path by its magnetic field. Much of the energy used to launch the material from a sunspot will be retained as it falls back to the sun's apparent surface. Its downward speed will be close to the upward speed it had when it was launched. The result will be that the returning material will make a hole comparable to the hole it was ejected from. This why I think that sunspots always occur in pairs. I have said that the jet ejected from a sunspot is too hot to emit many photons. Such a jet may be observed at the sun's limb during an eclipse. The jet acquires a new name in this situation. It is called a prominence. Prominences can only be observed easily during an eclipse because they are relatively dim. The dimness corresponds to my belief that they are too hot to emit many photons.
The energy source that can launch a jet that forms a prominence must have its origin well below the sun's apparent surface. The material and energy in the prominence when it returns to the sun's apparent surface must be of the same order as it had when it was launched. Its downward speed must be nearly the same as its original upward speed. I think that the returning material will go down to a depth comparable to that of the energy source that launched the jet originally. It could partially replenish the original energy source on the side where the jet fell back to the sun's apparent surface. This could keep the original jet going while dragging the source in the direction of the returning jet. This may offer a possible explanation why a pair of sunspots always move together. It could also explain why a pair of sunspots can last for several days.
A prominence caused by the sort of jet I have been discussing will consist of two parts. Most of it will not have enough launch velocity to leave the sun altogether. The other part will be a fraction that achieves the sun's speed of escape. It is that part which increases the strength of the solar wind when a lot of sunspots are visible.
What I have written here is based on a small number of basic principles and facts.
Lenz's Law (Direct quote)
An induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux.
A property of an electric current.
An invisible region around a source of magnetism that is always bipolar or circular.
A magnetic field will always occupy the minimum possible space. The magnetic path through ferrous materials is shorter than through air or vacuum. It is this fact that enables a magnet to attract ferrous items.
Magnetic lines of Force
Figments of somebody's imagination. When magnetic lines are a part of an explanation it indicates that the author is almost totally ignorant of the properties of magnetic fields.
An invisible emanation from the sun consiting of charged particles - mainly protons at the moment.
Photosphere (and apparent surface) 5,778K Inside (approx)15,700,000K
Gravity, 28 times Earth's. Speed of escape 617.7 km/s 386 miles/s
Most hydrogen is ionised at the sun's surface. All hydrogen is ionised at 10,000K
All helium is ionised at around 15,000K
Lenz's Law effectively states that an arrangement of moving metal within a magnetic field will have a magnetic field formed by an induced current that will be of the opposite polarity to the original magnetic field.
The ring current around the Earth caused by the interaction of the solar wind and the Earth's outer atmosphere as it rotates with the Earth creates a south seeking magnetic pole near the Earth's geographic north pole.
The magnetic field around the Earth is oriented north-south and deflects ionised particles arriving at the Earth sideways around the Earth. This deflection of particles is outside the earth's atmosphere around the equator and within the Earth's outer atmosphere in a ring around the poles.
The Sun, Summary
The sun is a colossal generator of heat. Most of the sun is ionised gas in the form of a plasma.
The heat of the sun causes gas to to form convection currents. Much of the gas in and around the sun is highly ionised by the heat available. When a gas is heated enough its atoms lose their outer electron shells.
The absence of outer electron shells means that there are fewer electrons available to fall from higher energy levels to lower ones. We perceive light and heat by the interception of photons. The consequence of this is that a gas that is hot enough will emit few photons. A convecting ionised gas forms an electric current.
All electric currents are surrounded by their magnetic fields. All magnetic fields detected on the sun are caused by moving streams of ionised gas. Sunspots are a source of some of the solar wind. The source of the energy needed to launch material away from the sun is well below the sun's apparent surface. Much of the material launched away from the sun falls back in an arc. When a very large amount of material is launched away from the sun, much of it will fall back and bore a hole that is nearly as deep as the hole it came from.
Wilf James BSc.