The Trouble with the Trifid
Mar 23, 2010

Before space probes and adaptive optics, all that astronomers had to study were twinkles in the night sky. So astronomy was almost entirely theoretical—twinkles in the mind’s eye. There were few opportunities to test the conceptual twinkles in a laboratory.

Space probes took the laboratories to the planets and to the spaces in between. New “optics” removed the twinkling and “looked” with all the wavelengths of the electromagnetic spectrum. The steady glare of data revealed the errors of the theoretical twinkles in astronomers’ eyes…but the familiarity, tradition, and consensus had crystallized in astronomical institutions like silver grains on a photographic plate: The old theories continued to twinkle in the eyes and to outshine the new twinkle in the skies.

Tradition twinkles again in the press release for ESO’s latest image of the Trifid Nebula. Turning a blind eye on a century’s research into the properties of plasma, the press release describes the nebula as “gas...heated by hundreds of scorching young stars until it emits the red signature light of hydrogen..., just as hot neon gas glows red-orange in illuminated signs....” Neon signs are, of course, plasma powered by electricity, and they are “hot” only in the sense of being electrified, not because they are “scorching.”

A similar twinkle of tradition obscures astronomers’ vision of the blue region at the top of the image. It’s called a “reflection nebula,” in which “dusty gas scatters the light from nearby, Trifid-born stars.” This explanation was reasonable, or at least familiar, when reflection was the only mechanism known for producing polarized light that had a spectrum similar to nearby stars. Later, the invention of the synchrotron contributed another possibility: blue polarized emissions of field-aligned electric currents twisting along magnetic fields.

The dark filaments that divide the nebula into thirds, hence giving it its name, Trifid, are called “gases and dust.” They will “collapse and form new stars” due to “gravity’s inexorable attraction.” This twinkle of explanation is entirely pretense. It’s contradicted not only by observations but also by traditional theory itself: Clouds of gas can collapse only if they have no angular momentum and no magnetism. However, for “some unknown reason,” all such clouds do have angular momentum and magnetism, usually a lot. As one astronomer has commented, “Astronomy has a spin problem.”

This is not a problem when the electrical properties of plasma are recognized: Birkeland currents generate spin, and the z-pinch effect is efficient at coalescing matter into filaments, disks, and dense spherules. One plasma physicist has called Birkeland currents the “vacuum cleaners of space.”

The traditional pretense of gravitational collapse then follows Alice’s rabbit into the wonderland of “rising density, pressure and temperature inside these gaseous blobs will eventually trigger nuclear fusion, and yet more stars will form.” Arthur Eddington, who proposed the internal thermonuclear power source for stars nearly a century ago, may be forgiven for his pretentiousness.

That Birkeland currents can transmit electrical power over interstellar and intergalactic distances was not yet known. Just as earlier astronomers had imagined the Sun to be a large campfire and then a large coal fire because those were familiar sources of light and heat, so Eddington could be expected to bring the newly discovered source of thermonuclear fusion reactions into the fold of the familiar. If he had been friends with Thomas Edison or Irving Langmuir instead of with Albert Einstein, he might have got a different twinkle in his eye, one that would have complemented instead of contradicted the space age discoveries.

The final twinkle of the press release is the “finger of gas pok[ing] out from the cloud, pointing directly at the central star.... This is an example of an evaporating gaseous globule….” From a plasma point of view, it’s an example of a stellar-scale comet—but not the familiar consensus-comet of sublimating dirty snow: it’s an electrical discharge sheath formation in the galactic current that powers the nebula. The stars that form in the tiny centers of the discharge pinches gain the notice of our eyes with their twinkling, but they are the least important of the vast electromagnetic structures in the plasma that fills what we traditionally call the vacuum of space.

Mel Acheson