Cosmology Notes

Gravity Theories

Modern cosmology has a disturbing number of free parameters.

Modified Gravity Theory (MOG)

John Moffat (of University of Toronto) proposes the Gravitational constant G is actually a new tensor varying with spacetime such that G/c is constant (Modified Gravity Theory). No dark matter or dark energy.

Expansion as illusion

There are many interesting alternative explanations of the observed Hubble relation of H₀ ≈ 70 km s⁻¹ Mpc⁻¹. The question is whether they raise more problems than they solve.

Tired light hypothesis

The hypothesis that light is red-shifted as it loses energy to the cosmos travelling across vast distances, through some unknown mechanism that does not result in photon scatter. One potential mechanism is the Wolf Effect, where diffuse plasmas can produce a redshift in transmitted light.

Time dilation

Using the antisymmetric temporal part of the Ricci tensor to replace the symmetric g tensor in General Relativity, it is possible to derive H₀ = c/R as a general time dilation of approximately 70 km s⁻¹ Mpc⁻¹, where R is the Einstein radius of the Universe (approx. 13 Gly). This would mean that the observed Hubble redshift relation results from time dilation across cosmological distances, rather than the relativistic motion of galaxies in an expanding spacetime.

Horizon problem and Olber's Paradox

If light is indeed red-shifted over vast distances, then an infinite static Universe would not be ruled out by Olber's Paradox since sufficiently distant radiation would drop out of detectable range, producing an effective observability horizon.

Surface brightness anomaly

Standard Big Bang cosmology predicts surface brightness (magnitude per unit area) decreases as (z+1)⁻³ yet observations show the surface brightness of galaxies up to z=6 are constant, as expected in normal non-expanding space. Explaining this as galactic evolution results in further difficulties.

Plasma physics

Cosmic Background Radiation

CBR as a local radio fog resulting from plasma scattering. This also predicts a long radio absorption with distance, which is indeed observed.

Long tortured history of CBR predictions, unexpected results, adding more free parameters, rinse and repeat.

Galactic rotation

Computer and laboratory simulations show that at least the ISM (if not the stars themselves) could be rotating as a plasma filament pair constrained by MHD, producing the observed flat rotation profile. These simulations also produce a time progression through the observed galactic spiral and barred spiral morphologies, and may also explain the observed independence of the motions of the stars from that of the spiral arms, if only someone would run the simulations again. However this substitutes "we need dark matter to make it work" with "where does the colossal current driving the filaments come from?"

Arp's quasars

Famous for his 1966 Catalog of Peculiar Galaxies. Anomalous redshifts of quasars, and their association with the minor axis of foreground galaxies.

Craziness? Okay try this on for size...

Electric stellar models

Electric Universe folks - crazy warning! Stars are (variously, composed mostly of molten iron) and are powered like an inside-out electric arc furnace. No requirement for "magnetic reconnection" which is a silly misunderstanding of fields anyway, can explain low neutrino flux without extra flavourings (fusion occurs in Z-pinches in the corona), and the 6000K surface temperature and 2MK corona follows naturally without shenanigans. No strange convection columns or lengthy radiative transfer required. Has other problems instead: where is the giant electric current coming from, and how is the star maintaining itself as an anode for billions of years without going dark? There's only so much H⁺ it can produce. Enter Oliver Manuel, famous for his meteorite isotope work which contributed to our current theories of solar system evolution. He believes stellar cores are collapsed supernova remnant neutron bodies, emiting H⁺ from n-n interactions:

Thus solar luminosity, solar neutrinos and solar-wind hydrogen coming from the surface of an iron-rich object that formed on a collapsed SN remnant are fingerprints of energetic neutrons in the solar core. These generate luminosity, neutrinos, and an outflow of 3 x 10⁴³ H⁺ per year in the solar wind.