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 Credit: B. Balick (U. Washington) et al., WFPC2, HST, NASA |
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Jun 21, 2005 Space-age images of planetary nebulas have forced astronomers to re-think their theories of stellar evolution. But if stars are composed of electrically active plasma, many of the most perplexing mysteries may already be solved. Since the advent of modern stellar-evolution theory, astronomers have believed that old Sun-like stars blow off their upper layers in spherical shells as their cores collapse into white dwarfs. But the theory continually faces new challenges as we learn more about these “planetary nebulas”. Why, and how, has the old Sun-like star in the image above constrained its ejecta into bipolar tubes with one inside the other? Why are the walls of the tubes so sharply defined? Why are the walls composed of filaments? Why are many of the filaments paired? Why do many of the filaments have knots of luminosity along them? Why are they green? Why is there a torus (“donut”) of plasma (too small to be seen in this image) circling the “pinched” part of the tubes? Why is the central star actually a binary? Every aspect of modern stellar-evolution theory is beset with similar lists of questions. The questions arise because new discoveries almost always provoke astonishment. The theory did not anticipate them. Typically, when astronomers propose answers, they appeal to single-case exceptions or resort to after-the-fact adjustments. The lack of predictive ability leads to increasing complexity and confusion, and the astronomers’ credibility rests increasingly on the new hedge factors they introduce. “If this is knowledge, astronomers would be better off with ignorance,” said one critic. We can expose the heart of the problem by simply counting the words used as unexpected difficulties arise: The word “gas” appears almost always; the word “plasma” appears almost never. When pressed, astronomers will admit that their “gas” is actually “plasma”. But what they mean by “plasma” is “hot gas”: Instead of applying the electrical equations of plasma behavior, they resort to the equations of gas kinetics. One begins to suspect they “don’t know their gas from their plasma”. An electrical discharge in plasma will generate a tube-like sheath along its axis. A sufficiently energetic discharge will cause the sheath to glow, and it may generate several embedded sheaths. The sheath is actually a “double layer”, a thin sheet in which positive charges build up on one side and negative charges build up on the other. A strong electrical field exists between the sides. This field accelerates some of the charges and emits microwave (and often optical and x-ray) radiation, but is otherwise undetectable unless a probe flies through it. (Hence, astronomers, who have only recently learned to look for magnetic fields, assume double layers don’t exist in space.) In the image of the Butterfly Nebula above, the double layers are glowing, revealing themselves as the sharp boundaries of the sheaths. Electrical currents flow along these sheaths. In plasma, electrical currents pinch themselves into thread-like channels—filaments. These filaments attract each other, usually in pairs, at long distances, but repel each other at close distances. Instead of merging, they spiral around each other. Fluctuations in high-energy currents will lead to instabilities that alternately squeeze and expand the filament, making it look like a string of sausages or a row of beads. Because the light is produced by electrical discharge, the relevant model for a nebula is a laboratory “gas-discharge tube”, similar to a neon light, which emits light only at the excitation frequency of the gas. Astronomers’ model of a shock wave from an explosion predicts emitted light at many frequencies due to heating of the gas. But over 90% of the light from planetary nebulas comes in a single frequency: that of doubly ionized oxygen. Think of the Butterfly Nebula as a light-year-long oxygen discharge tube. In an Electric Universe, stars form in “kinks” in a discharge channel. Where the channel bends, matter tends to accumulate. It forms a spinning sphere in which external electromagnetic “pinch” forces are balanced by internal pressure from the increasing density of plasma. Laboratory experiments show that this sphere has an equatorial plasma torus—a ring current—around it, just as do the central stars of planetary nebulas. This ring current stores charge until it reaches its capacity, at which time it discharges to the inner sphere, producing a flash of light with the characteristic sudden onset and exponential decline of a lightning bolt—the same thing we see in a stellar nova. If the electrical stress on the central star (which acts as an electrode) becomes too great, it will fission into two or more bodies, thereby increasing the surface area of the electrode so that it can accept a greater current load. This likely explains why most if not all central stars in planetary nebulas are double. From an electrical vantage point, the stellar-evolution theory was a triumph of gaslight era astronomy. It explained most of the data that could be gathered by ground-based mechanical sensors. But the advent of electronic sensors in space and the realization that the universe is composed almost entirely of plasma requires a theory that takes electricity into account. To see that we live in an Electric Universe, it is only necessary that we compare the predictive abilities of the two models. See: Dec 24, 2004 On the Wings of a Butterfly |
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