March 7, 2010

Disks in space

After having introduced a hypothetical model of elementary particles and the way they cause gravitation, it is natural to evaluate the hypothesis from a cosmic view! This may sound contradictory, or even arrogant, but it is not totally far-fetched. The gravitational field created by the discussed particles is quite special, and gravitation is the known force that works on the cosmic scale.

Planar gravitation
The predicted gravitational field is confined to two dimensions and concentrated in one plane defined by the elementary particle. In my opinion, a two-dimensional gravitational field is even suggested by the inverse-square nature of gravitation. Elementary particles and atomic nuclei are usually randomly orientated to each other, meaning that the sum of elementary gravitational fields is perceived as radiating in three dimensions from the body of mass. But one can think of conditions were particles align to concentrate the gravitational field in a common plane!

For particles to fix their position relatively to each other, their gravitation has to overcome their thermal motion. This requires either a very strong gravitational field, or very cold particles. Further, nuclei in free atoms, or nuclei bound in a common plane, will more easily align. In molecules were nuclei are restricted to different planes, not all nuclei can contribute to planar alignment at any time. Anyhow, the total gravitational field will not perfectly reduce to two dimensions, considering that some wobbling is expected due to thermal motion.

So where would be best to look for the effects of planar gravitation? Probably in extensive accumulations of extremely cold gas...

Spiral galaxies
Galaxies consist of astronomical(!) numbers of stars and other matter, bound together by gravitation. Our own Milky Way is classified as a spiral galaxy, which in general consist of two parts: A rotating disk where new stars are constantly forming from abundant gas, and a central bulge of mostly older stars. The bulge is shaped like a spheroid, and has very little gas compared with the disk.

Apparently, the rotational velocity of the outer disk is too high to be balanced by gravitation from the visible matter in spiral galaxies! This is usually justified by the concept of “dark matter”, first suggested by Fritz Zwicky in 19331 to explain dynamics of galaxy clusters. In spiral galaxies, “dark matter” is supposed to be contained in a spherical halo surrounding the visible disk2. It has never been detected.

Another explanation for the rotational dynamics of spiral galaxies could possibly be planar gravitation. If most of the gravitation from interstellar gas is contained within the plane of the disk, extra “dark matter” may be superfluous!

Planar gravitation could even explain the high velocity of orbiting galaxies in galaxy clusters. If this is the case, spiral galaxies should orbit the centre of their cluster edge-on.

Elliptical galaxies
Not surprisingly, these galaxies are shaped like ellipsoids (including spheroids). Like bulges of spiral galaxies, they are dominated by older stars and contain very little gas. No disk. They are usually found centrally in galaxy clusters.

Interestingly, they may lack “dark matter”! The velocity dispersion of the stars seems to be adequately explained by the visible matter contained in them3. Complex models have been introduced to put “dark matter” into ellipticals4.

Planetary rings
Four of the planets in our solar system have each an annular disk in orbit. These are the gas giants: Jupiter, Saturn, Uranus and Neptune. The disk around Saturn is the most impressive by far, and the one most people associate with planetary rings. The disks consist of water ice, small particles and gas. Even though gas may only constitute a small fraction of the orbiting matter, the sheer size of the systems allows for a lot of gas! One can speculate if the stability of the disks is due to aligned gravity of their gas components...

Disk-formations in space seem to be easily explained by two-dimensional, planar gravitation – either in agreement with the presented model of elementary particles, or not.

1 Zwicky F (1933) Die Rotverschiebung von extragalaktischen Nebeln. Helvetica Physica Acta 6:110–127

2 Exactly how the “dark halo” is supposed to restrict the visible matter to a disk remains enigmatic to me.

3 Romanowsky AJ et al. (2003) A dearth of dark matter in ordinary elliptical galaxies. Science 301:1696–1698

4 Dekel A et al. (2005) Lost and found dark matter in elliptical galaxies. Nature 437:707–710

No comments: