The coverage of the relationship between an electric current and a magnetic field in the essay Planetary Magnetism - A Heretic's View applies equally to other astronomical phenomena. For example, the relationships between sunspots, solar prominences and the magnetic fields around sunspots conform to the basic rules of electricity and magnetism.

A prominence starts as an upward jet emerging from the sun's depths at a high velocity. The jet is ionised and thus creates a constrictive magnetic field around itself. The intensity of the magnetic field falls off as the jet decelerates. The jet widens. As the jet loses upward speed, coriolis force moves it sideways, giving it some sideways speed.. This provides a weak magnetic field that still offers some constraint on the jet's width. It is now broad and horizontal. Gravity pulls the jet back towards the sun at an increasing speed. Correspondingly the magnetic field around the jet becomes stronger and more constrictive. The jet narrows again. As the jet returns to the sun's 'surface' it has regained most of its upward speed in a downward direction. It makes a hole comparable to the one it emerged from. The magnetic field around this hole is opposite to that around the hole from which it emerged.

The illustration shows that the magnetic field weakens somewhat during the path of the jet so that the jet is broader as it returns to the sun's surface. The sizes of the arrows in the path of the jet symbolise the weakening of the jet.

The narrow high speed jet penetrates downward, near to the region from which it originated.
It thus provides heat and material to replenish its original source. This replenishment can explain why some prominences and sunspots last for days on end. The sunspot movement is explained by the action of coriolis force on the jet. Some jets are clearly visible but many are invisible against the brightness of the sun's photosphere. This is why most prominences are only seen sideways on during an eclipse.

The prominence shown has a visible height above the sun's surface of at least 215,000 kilometres and extends around the sun's circumference 600,000 kilometres. In comparison the Earth is 12,756 kilometres in diameter. The prominence as seen here is nearly 17 Earth diameters high and nearly 47 Earth diameters in width. These are jets that do not quite achieve escape velocity. Please note that the view here does not show the parts of the sun where the prominence comes form or where it goes to. These places are beyond the sun's horizon in the image.

Sunspots are always in pairs and of opposite magnetic polarities. The movement of sunspots around the sun is a function of the suns's rotation. Coriolis force caused by the sun's rotation deflects the upward jet sideways. The downward jet is thus displaced from the source of the upward jet. The replenishment of the source of the upward jet by the downward jet is one-sided, tending to pull the upward jet towards the point of penetration of the downward jet. The pair of sunspots thus move around the sun at a speed which is different to the sun's rotational speed.

It may be noted that sunspots move diagonally towards the equator.
The prevailing winds on Earth move likewise, also because of coriolis force. It is therefore illogical to say that the sun rotates at the same speed as the sunspots rotate. It would be as logical to say that the Earth rotates as fast as the prevailing winds rotate. Nevertheless, I have found that the sun's rotation is claimed to be the same as the sunspot rotation in books on astronomy.

In some astronomy books the formation of sunspots is explained in terms of magnetic lines of force. As magnetic lines of force are only imaginary, an explanation based on these "lines" leaves something to be desired. Even more strangely, these "magnetic lines of force" take the form of a hairpin which wraps itself completely around the sun. The free ends of this hairpin shape somehow get twisted and tangled and thereby form sunspots magnetically. The illustration of the path of a jet and its associated magnetic fields (shown above) can serve as a sort of model for this hairpin shape - if it can be imagined to be horizontal instead of vertical. The next question is: how could movement of ionised gases form such a magnetic shape? I am sure that if an astronomer tried to find a satisfactory explanation for the elongated hairpin shape that would satisfy electrical/electronic engineers, he would find it impossible.

Conventional explanations of sunspots refer to magnetic loops formed across the surface of the sun.. What sort of movement of ionised gas could produce a magnetic loop (like a small rainbow as illustrated) above the surface of the sun?

Moving ionised gas makes the magnetism. What is more likely to emerge from a boiling surface - gas or magnetism? Are the gases more likely to be moving up and down or sideways across the surface ? Isn't it more likely that the gases should move like miniature solar prominences and make arcs comparable to the jet illustrated at the beginning of this essay?

Additional Notes 30/06/2006
If it can be accepted that there is an accumulation of pressure below the surface of the sun that causes material to be ejected in the form of a jet, what would br the upward speed of the jet if it was the basis of a solar prominence? I have done some very basic calculations which do not allow for atmospheric drag. The figures have been derived from the formula V²=2aS. V= velocity in metres per second. a= acceleration due to the sun's gravity. S= the height reached.
The sun's gravity is taken to be 27.9 times g = 27.9×9.81=273.7m/s². The sun's diameter is taken to be 1,392,530,000 metres. The calculations were done for prominences that rise above the sun's surface as percentages of the sun's diameter. The velocity shown is the initial upward velocity at or near the sun's surface.

The 15.4% height figure is derived from the image of the prominence provided by NASA. 343,249m/s = 213 miles per second. (The international space station orbits the Earth at around 5 miles per second.) This figure illustrates the enormous energy involved in the projection of a prominence so high above the sun's apparent surface. The source of this energy is heat coming from the sun's interior.

As prominences are dim when compared with the brightness of the photosphere, they must be emitting fewer photons per unit of observed area. Since photons are emitted from atoms when electrons fall from one energy level to a lower one, the temperature of the gas in a prominence could be so high that electrons are inhibited from falling to lower energy levels. If this is the case, the same conclusion would have to be applied to sunspots which are apparently dimmer and cooler than the surrounding photosphere.

A prominence is a jet of ionised gas which forms an electric current as it moves upward. This current creates an annular and constrictive magnetic field around the jet. This creates an effective venturi which accelerates the upward speed and causes cooling. As the jet ascends it decelerates causing the magnetic field to become weaker. The constrrictive effect is reduced which allows the gas to expand in volume. The Joule-Thompson effect is in force, causing the temperature of the gas to cool. As sunspots are generally observed through the transparent jet, this may contribute to the fact that they appear to be cooler than the photosphere.

The colossal velocities needed to launch prominences to significat heights above the sun's visual surface could not be created by magnetic fields wrapped around the sun (as is claimed by Babcock and quoted in most astronomy books). Such magnetic fields would have to be caused by extremely fast differential horizontal movements of ionised gas, moving through the dense atmosphere at the sun's surface. Because of drag and other losses, the horizontal velocity of ionised gas would have to be much higher than the upward velocity of the resulting jet to cause the (supposed) magnetism needed to create the jet..

A Simple Experiment
Have a look at some (savoury) rice boiling in a saucepan, just before all the water has gone. You may see some similarities with sunspots. The action of heat is similar. The interior of the sun is hotter than its surface. The bottom of a saucepan is hotter than the surface of the rice. Gas expands when heated unless constrained. Material at and just below the sun's surface acts as the constraint. If the gas is constrained its pressure increases. When the pressure is high enough, it bursts through the constraining material at the sun's surface explosively, making a hole The water heated at the bottom of the saucepan is heated beyond normal boiling point because of the pressure of the overlying rice. When the steam pressure is high enough, it bursts through the surface. The released steam makes holes. However, the emerging steam is not ionised and does not fall back into the rice to make more holes. I have yet to see steam emerging sideways from boiling rice.

Conclusion
It would seem that the writers of many astronomy books have based their researches on what someone else has written previously without checking if the previous work is in agreement with the basic fundamentals of electronic physics. This essay and "Planetary Magnetism - A Heretic's View" are based on just two testable facts. Magnetic lines of force do not exist and a magnetic field is always formed at 90 degrees to the current which generates it. It is assumed that gases in the sun comply with Boyle's Law. It would seem that astronomers just assume magnetism is present without describing a means for its production. Their other descriptions of magnetism and how it affects ionised gases directly contradict what electrical and electronic engineers have found to be the case empirically.

New Notes 14th September 2005
I have recently seen some views of the sun in the BBC television programme called 'The Sky at Night'.
The views particularly relevant to this essay are of the many arcs that occur just above the sun's surface. They are of many sizes and have a resemblance to the sketch shown at the beginning of this essay. In the images that I saw, all appeared as being brighter than the background and apparently long lived. The given explanation for these arcs and other phenomena was the same. 'They are created by the sun's magnetic fields'. I know of no magnetic field organisation that could create hundreds of similar arcs in illuminated gases. The appearance of these arcs was reminiscent of looking at long grass in a lawn that had not been cut recently. The arcs were numerous and discrete entities. In some ways they were like hundreds of little fountains. In my opinion they are fountain like. They are created by ionised gases emitted from the surface of the sun that form thin fountain like arcs that are constrained by the magnetic fields that they create for themselves. The images I saw vibrated and oscillated in size, adjacent arcs moving more or less together at their tops, a bit like adjacent blades of grass blowing in the wind. The discreteness of the arcs indicates that they are in some ways comparable to the lines of iron filings that form on a sheet of paper above a bar magnet. The reason is similar. They have magnetic fields that are mutually repulsive. However, this can only be true if a pair of adjacent arcs is formed from sources and destinations that are opposite to one another. Two arcs which originated in adjacent sources would coalesce because their two magnetic fields would be mutually attractive. Adjacent arcs of gases moving in opposite directions would be mutually supportive to some degree. The gases and energy from one arc arriving at its destination would provide some replenishment to the other arc at its source.

Wilf James BSc.
Copyright © 13th March 2000 & 14th September 2005
Please note:
A new text which includes a different approach to this essay is covered in Basic Electricity and Magnetism for Astronomers .
8th June 2009

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