Stellar mass and Birkeland's flying corpuscles
FYI, he finished up all his calculations including electrons on page 721 with the following statement:
We see from the above that it is not impossible that future investigations will show that without coming into conflict with experience in any way here mentioned, we may reckon that there are more than ten thousand times greater masses gathered in flying corpuscles in "empty" space than the masses in the stars and nebulae.
Oh. So Birkeland was just guessing. And what exactly, in objective and quantitative terms, are corpuscles? Looks like Birkeland had a hunch scientists might find that dark matter stuff.
You're no scientist or you would know that he wasn't just "guessing".
Lets repeat the Birkeland quote with different hilite:
We see from the above that it is not impossible that future investigations will show that without coming into conflict with experience in any way here mentioned, we may reckon that there are more than ten thousand times greater masses gathered in flying corpuscles in "empty" space than the masses in the stars and nebulae.
Oh, of course Birkeland was guessing! Even Birkeland knew he was guessing. That's why he said, in the very passage you quoted, "
it is not impossible" that future scientists would discover all those flying corpuscles out-mass the stars (and nebulae!) by a factor of 10,000. Birkeland knew that he had no
direct knowledge of the interplanetary or interstellar flying corpuscles. All he had was
indirect knowledge derived from his interpretations of his own laboratory experiments, plus his own interpretation of auroral phenomena.
Well, today we have
direct knowledge of the interplanetary corpuscles. We measure them directly with spacecraft immersed in those corpuscles. We know that the number density of the solar wind, in the vicinity of Earth's orbit, is on average about 7 protons & electrons per cubic centimeter. If we assume that density on average throughout a sphere 100 astronomical units (AU) in radius, I get a total mass of about 1.642x10
17 grams. That is about 0.0032% of the total mass of the atmosphere of planet Earth. Not exactly a dynamical monster in the presence of the entire solar system, which is dominated by the 1.989x10
33 gram mass of the Sun.
But of course, Birkeland is referring to "stars and nebulae", so he must clearly mean to speak about the environment far beyond the Sun and solar system. But Birkeland did not even have
indirect data of any kind on that environment. All he could possibly do is extrapolate based on his determinations of the solar system environment. But of course he was already just guessing about that, so his ideas about the interstellar environment can only be an extrapolation from a guess. And since "extrapolation" is as often as not a pretty good synonym for "guess", what Birkeland is actually doing is making a guess based on a guess, which is pretty much "guessing" in my book.
But today we have strong indirect knowledge of the content of the interstellar medium in galaxies, based on extensive multiwavelength astronomy campaigns (radio, infrared, ultraviolet and X-ray astronomy being the chief contributors).
I'm still struggling to get you and Sol to acknowledge that the mass contained in stars is merely 'chump change" compared to the mass that is contained in the plasma filaments between the stars.
Then you are in real trouble. The mass of the filaments in a spiral galaxy amounts to about 10% of the galaxy's baryonic mass, the rest being stars. And of course, in elliptical galaxies there are generally no such filaments at all.
I posted that while off on a trip to the Riverside Telescope Makers Conference, and away from my library. Now that I have returned, allow me to elaborate.
"The visible mass of galaxies is primarily in the form of stars. Gas, even in the case of the so-called late-type spirals that have the largest gas content, does not contribute more than a few percent of the total mass. However, because the various forms of matter have different spatial distributions, it should be kept in mind that, in some locations, the gas content can be significant. For example, in the outer disks of spiral galaxies the gas-to-star surface density ratio can easily exceed 15%. In the case of elliptical galaxies, traditionally described as gas-free systems, there are examples, such as NGC 4636, in which almost 10
11 solar masses (i.e., ~10% of the estimated stellar mass) is in the form of hot, X-ray emitting gas; this hot corona occupies a volume larger than that of the luminous content."
Dynamics of Galaxies by Giuseppe Bertin, Cambridge University Press, 2000.
Clearly, even on galactic scales, the idea that the mass contained in stars is "chump change" is quite wrong. Only when we reach the scale of galaxy clusters, do we see the intracluster hot gas take the leading role, out-massing stars by about 9 to 1. Whether or not this constitutes "chump change" is surely subjective. However, it does make the point that even at galactic scales, stellar mass dominates. And even in galaxy clusters, the intracluster medium is extremely tenuous, with a number density of about 1/1000cm
3 (10
-3/cm
3), and occupies a volume far greater than the volume occupied by galactic stars (there are also quite a lot of intracluster stars, not associated with or bound to any specific galaxy in the cluster). But we also know that this hot gas that out-masses the stars by 9 to 1 is still about a factor of 10 too little to maintain the cluster in gravitational equilibrium, hence the need for dark matter to supply the additional "missing mass". See, for instance,
Loewenstein, 2004;
Dynamics of Galaxies by Giuseppe Bertin, Cambridge University Press, 2000;
Galaxies in the Universe: an Introduction by
Linda Sparke and John Gallagher, Cambridge University Press 2007 (2nd edition).
Modern, direct & indirect observational evidence is explicit and clear in completely rejecting Birkeland's notion that the "flying corpuscles" (which we now identify more explicitly as electrons, protons, and various neutral & ionized atomic and molecular gases) out-mass the stars & nebulae by a factor as large as 10,000. In reality, averaged only over distance scales that span galaxy clusters (~2 Mpc or ~6,500,000 light years), then the "flying corpuscles" can fairly be estimated to out-mass the stars by about a factor of 9 or 10. However, averaged over smaller spatial scales, importantly including one or a few galaxies, then the mass contained in stars is significantly greater than the mass of the "flying corpuscles" in the same volume.
That's the whole point Ben. The cosmic wind blows against the galactic sails and the galaxies 'move'. It's not magic, it's physics!
No, it most certainly is not physics. It is not even very good magic. It's just plain impossible and there is no way around it. Guth's idea of inflation is a far better idea, makes far more sense, and has the added advantage of not postulating phenomena that are so easily shown to be simply
physically impossible.