Hydrogen primordial

Helium is the second most abundant element in the universe (76% H, 23% He) as a result of its synthesis from hydrogen (p. 9) but, being too light to be retained by the earth s gravitational field, all primordial helium has been lost and terrestrial helium, like argon, is the result of radioactive decay ( He from a-decay of heavier elements, " °Ar from electron capture by... 

With the advent of 8- to 10-metre class telescopes in the 1990s, it became possible to approach the primordial deuterium problem more directly, by measuring the isotopic component in absorption lines of hydrogen due to intervening gas along... 

The D/H ratio of the sun is essentially zero all the primordial deuterium originally present has been converted into He dnring thermonuclear reactions. Analysis of primitive meteorites is the next best approach of estimating the hydrogen isotope composition of the solar system. 

Primordial nucleosynthesis really puts the Big Bang cosmology to the test. One might call it a baptism of fire. From these brief but brilliant and fertile beginnings arose a series of light nuclei that are today found everywhere in nature above all hydrogen, followed by helium, which between them amount to 98% of the total mass of atomic matter in the Universe. 

A few years ago, when present theories concerning the formation of the universe were proposed, cosmologisis suggested that only hydrogen and helium and also lithium, in very small concentrations, were present in the primordial matter. It was postulated that all other elements were produced as the result of subsequent star formation through nuclear reactions or cosmic ray radiation, thus creating all of the elements in die Periodic Table. 

Craig, H., Lupton, I. (1976) Primordial neon, helium and hydrogen in oceanic basalts. Earth Planet. Sci. Lett., 31, 369-85. 

In fact, the D/H has been recently measured in several high-z hydrogen clouds. These hydrogen clouds are seen by their distinctive Lyman-alpha features in the spectra of several QSOs. Here, we consider the new results reported by Kirkman et al. (2003) they announce the detection of D in an absorption system at z=2.526 in the spectrum of Q1243+3047 they show how they have improved the exploration of some factors which determine the measurement errors. We adopt their best estimate of the primordial D/H values towards five QSOs ... 

Metal and metal oxide catalysts with this capability were reported in the 1980s. Several of these metals occur in widely distributed petroleum samples and are among the above listed as constituents of primordial Earth planetary orbit dust. In the metallic and compounded state some have the ability to catalyze hydrogenation of carbon to kerogen like high viscosity hydrocarbons. Kerogen, a heavier petroleumlike hydrocarbon mixture occurs in tar sands and porous shales (oil shale). Thus the question of conceivable prehistoric or more recent petroleum from methane generation must be considered. 

The observations summarized in the previous sections indicate that most disks disperse their primordial dust and gas on a timescale shorter than lOMyr. Part of this primordial material may be incorporated into planets. However, planet formation is not the major disk-dispersal mechanism. In the case of our Solar System the mass of the planets amounts to less than one tenth of the minimum-mass solar nebula, which is the minimum disk mass required to reproduce the solar chemical composition (0.013-0.036M Hayashi et al. 1985 Desch 2007). With hydrogen and helium largely depleted in planets (see e.g. Weidenschilling 1977),... 

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