Theories of Galaxy Evolution ask: How Green is the Valley?

GALEX measurements of nearby galaxies showing a green valley in the evolution between the blue cloud of young stars and the red sequence of older stars is explained without the Doppler effect by QED redshift of absorbed UV in cosmic dust
By: Thomas V. Prevenslik
Star UV emissions colored by cosmic dust
Star UV emissions colored by cosmic dust
June 14, 2011 - PRLog -- Background
Our understanding of nearby galaxy evolution has been recently advanced by UV measurements [1] from NASA’s Galaxy Evolution Explorer (GALEX) satellite. Imaging was performed in both the NUV and FUV at 230 and 150 nm, respectively. See  Young stars having intense UV emission are thought to appear as a blue cloud of star forming spirals while older stars look like the sequence of red ellipticals. However, GALEX also shows light at frequencies half-way between the blue and red – the so called green valley [2].  In galaxy evolution, the green valley corresponds the color of the average frequency  between red and blue frequencies differing from that in painting, i.e., a green watercolor is produced by mixing yellow and blue - not red and blue. Regardless, making color a measure of galaxy evolution is complicated by the fact the observed star color is that of the surrounding cosmic dust having nothing to do with the color of the star itself. See , “The Green Valley,” 2011.  

Stars naturally produce cosmic dust that scatters and absorbs their emissions. Scattered light is eventually absorbed, and therefore our measurement of UV emissions from young and old stars is always altered by cosmic dust. Cosmic dust typically consists of submicron dust particles (DPs) from 0.005 to 0.5 microns. Astronomers think the IR light observed from a star is caused by the temperature increase of the cosmic dust upon the absorption of UV photons. Classical physics is assumed to determine the temperature increase of the DPs upon the absorption of a single photon, as instantaneous multi-photon absorption is unlikely.  Based on the computed temperature T of the DP,  the wavelength Lo of IR emission is then given by Wien’s law of thermal blackbody radiation, i.e., LoT = 2898 micron-K. For example, our yellow sun at Lo = 575 nm has a temperature of ~ 4050 K. In the thumbnail, the red color represents IR emissions from cosmic dust based [1] on AKARI data.  Since the maximum detectable IR band wavelength of AKARI is 160 micron, the DP temperature resolved upon absorption is ~ 18 K.      

However, classical physics is not valid in deriving the thermal response of submicron DPs because their heat capacity is restricted by quantum mechanics (QM). Unlike classical physics that allows the atom to have heat capacity from the macro to the nanoscale, QM requires the heat capacity of submicron DPs to vanish. Conservation of the absorbed UV photon therefore cannot proceed by an increase in DP temperature.  

QED Induced Radiation
Lacking heat capacity, QM conserves the absorbed UV photon by the creation of QED radiation inside the DP. QED stands for quantum electrodynamics.  Creation is prompt with QED inducing the absorbed UV photon to assume the EM confinement of the DP by TIR. EM stands for electromagnetic and TIR for total internal reflection. TIR confinement only occurring during the absorption of the UV photon is a natural consequence of submicron DPs that have a high surface to volume ratio. What this means is the energy of the absorbed UV photon having wavelength L is almost totally confined to the surface of the DP, and therefore the wavefunction of the created redshift photon is given by the TIR resonance and defined  by the DP diameter D and refractive index n. Over this time, the created QED photon is emitted at wavelength Lo, where the redshift Z = (Lo-L)/L and wavelength Lo = 2Dn.   Only redshift of the UV photon to a lower energy QED photon may occur; blueshift is not possible with single photon absorption. See diverse QED applications in , 2009-2011.


Green Valley Not only does cosmic dust redshift the UV photons to the IR without a temperature increase, but the UV is also redshift by QED to produce the VIS colors from the blue through the green to the red. Hence, the color of a galaxy is neither blue nor red, but may have a color in between. Indeed, QED redshift may be considered to produces the entire EM spectrum upon the absorption of UV by cosmic dust, the color depending on the size and material of the DPs while the intensity depends on their number.  In a random distribution of DPs, the most likely DP is its average which corresponds to a green color because green is the average frequency between blue and red.  But the green color is not unique as other DP distributions produce different colors.

Wavelength  QED redshift of the UV radiation from a galaxy depends on the dimensions and materials of individual DPs. Hence, QED redshift within a cosmic dust cloud is not the same everywhere as in Hubble’s law. However, the evidence for the same Doppler redshift for all wavelengths required by Hubble’s law is not convincing. For example, the redshift for the calcium H and K lines shown in (Fig. 22-1 of [3]) for redshifts Z from 0.004 to 0.204 is only qualitative. Measurements of calcium H and K lines to show they are redshift the same amount for the same Doppler redshift Z are not given. Generally, astronomers accept Hubble law without proof of its validity. For example, the AKARI-GALEX data (Fig. 5 and A-1 of [1]) at low redshift Z < 0.15 simply assume [1] the validity of the standard cosmological model with Ho =70 km Mpc /s.  Doppler redshift data that actually prove calcium H and K lines redshft the same would certainly be convincing.  

Comparison Differences between QED and Doppler redshift may be compared to determine if the UV photons can be redshift to green photons, i.e., a  redshift of  Z = 1.28 is required to create a 525 nm green photon from a 230 nm NUV photon.  But AKARI-GALEX data is limited to Z < 0.15, and therefore green photons cannot be produced by the Doppler redshift. But green photons are observed,  and therefore it follows that Hubble’s law fails at Z < 0.15, or for that matter for all Z. In contrast, the QED redshift of Z = 1.28 to create a green photon from the NUV is easily achieved in a 175 nm DP having a 1.5 refractive index. Hence, it is likely Hubble actually observed QED redshift in cosmic dust.


1.  Color has nothing to do with the age of the star. Color depends on UV absorption by surrounding cosmic dust. Young stars need not emit blue light, and instead may emit red light or even IR light depending on the properties of the cosmic dust. Certainly, old stars emit less UV than young stars, but otherwise the star color depends on the absorption of UV emission by cosmic dust.

2. In galaxy evolution, the green valley is a composite of a rainbow of VIS colors produced by the absorption of UV radiation emitted by the star in the surrounding cosmic dust. QED redshift for the absorption of 150 to 230 nm UV radiations in submicron DPs produces VIS light from the blue at 380 nm to the red at 760 nm.  

3.  The AKARI-GALEX conclusion that a large majority of young stars are hidden by cosmic dust is consistent with the conclusion here that color has nothing to do with the age of a star. However, the large amount of cosmic dust observed today does not suggest an early transition from a transparent to dusty Universe consistent with the Big Bang scenario, but rather that cosmic dust was always there consistent with an infinite Universe once proposed by Einstein.                    


[1] Takeuchi, T. T., et al., “Star formation and dust extinction properties of local galaxies from the AKARI-GALEX all sky surveys,” A&A, 514, A4 (2010).
[2] Gocalves, T . S. and Martin, D. C., “Quenching Star Formation in the Green Valley: The Mass Flux at Intermediate Redshifts,”  Stellar Populations - Planning for the Next Decade Proceedings IAU Symposium No. 262, (2009).
[3]  Zielik, M. and Gregory, S. A. Introductory Astronomy and Astrophysics, 1st Edition, Saunders College Publishing, 1987.

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About QED Induced EM Radiation: Classically, absorbed EM energy is conserved by an increase in temperature. But at the nanoscale, temperature increases are forbidden by quantum mechanics. QED radiation explains how absorbed EM energy is conserved at the nanoscale by the emission of nonthermal EM radiation.
Source:Thomas V. Prevenslik
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