Helium in the Sun

Hydrogen is converted to helium in the sun little by little in terms of the total amount of hydrogen present. In terms of the actual rate of conversion—about 5 billion tons per second— hydrogen is converted to helium in the sun at a phenomenal rate. 

Kirchhoff s and Bunsen s results created a sensation within the scientific community. Soon scientists throughout Europe were using spectroscopes in their research. Inevitably, some of them found yet more new elements. In 1861 the English chemist and physicist William Crookes discovered thallium, a heavy metal, in a sample of clay. In 1863 two German chemists, Ferdinand Reich and Hieronymous Richter, discovered another new metal, which they called indium. And in 1868 the French astronomer Pierre Jannsen observed the sun with a spectroscope during an eclipse and discovered the spectral lines of a new element, helium, in the sun s atmosphere. This was an especially sensational discovery, because helium had never been observed on Earth. 

Birth of Marie Sklodowska (Mme. Curie) at Warsaw, Poland. Janssen and Lockyer independently observe the D line of helium in the sun s chromosphere. 

Frankland, Sir Edward (1825—1899). A British chemist noted for research on organic-metallic compds, valency, water supply and the theory of flames. Discovered, in collaboration with Brit astronomer Sir Joseph Lockyear (1836— 1920), helium in the sun s chromosphere Ref Hackh s Diet (1944), 355-L St 498-L... 

To set an abundance scale for listing the abundances of the elements, astronomers usually set H = 1012 atoms. Other elemental abundances in stars are then given by their numbers per thousand billion H atoms. In the Sun the ratio H/He = 10. For 3He more reliable information about relative He isotopic abundances comes from the primitive classes of meteorites, which are dominated by silicon. Thus the scale frequently used for geochemistry and for stellar nucleosynthesis takes a sample containing one million Si atoms, so that abundances of the elements are then their numbers per million Si atoms. Since helium in the Sun is observed by astronomers to be 2720 times more abundant than silicon, the He total solar abundance is therefore... 

That is just what happens. The present-day abundance of helium in the Sun, for example, is about 22 percent. It is 28 percent in massive young stars and anywhere from 26 percent to 29 percent in the interstellar medium. Averaging the data found in many studies, astronomers suggest that the present-day abundance of helium throughout the universe is about 24+1 percent, in very good agreement with calculations based on the big bang theory. 

The discovery of earthly helium and an addition to the Periodic Table to include it both resulted from a new line of experiments which had nothing to do with the discovery of helium in the sun. 

The lines of helium in the sun s spectrum were responsible for the discovery of this element in the sun twenty-seven years before it was known on earth. 

Elemental abundances. (A) Helium. Solar models are able to deduce accurate, although somewhat model-dependent, protosolar He values by fits to the observed present-day luminosity (e.g., Christensen-Dalsgaard 1998, see Helium in the sun section). The value stated in the body of Table 2 in three different notations is from the compilation by Grevesse and Sauval (1998), two other values for the initial He mass fraction are given in the Table caption (see also next section). In summary, the models provide the protosolar He abundance with an uncertainty of only a few percent. 

Orbitals do not need to have electrons in them—they can be vacant (there doesn t have to be someone standing on a stair for it to exist). Helium s two electrons fiU only the Is orbital, but an input of energy—the intense heat in the sun, for example— will make one of them hop up into the previously empty 2s, or 2p, or 3s... etc. orbitals waiting to receive them. In fact, it was observing, from earth, the energy absorbed by this process which led to the first discovery of helium in the sun. 

He propounded the theory of valency and, with Joseph Lockyer, discovered helium in the Sun s atmosphere in 1868. 

Gr. helios, the sun). Janssen obtained the first evidence of helium during the solar eclipse of 1868 when he detected a new line in the solar spectrum. Lockyer and Frankland suggested the name helium for the new element. In 1895 Ramsay discovered helium in the uranium mineral clevite while it was independently discovered in cleveite by the Swedish chemists Cleve and Langlet at about the same time. Rutherford and Royds in 1907 demonstrated that alpha particles are helium nuclei. 

In 1868, within a decade of the development of the spectroscope, an orange-yeUow line was observed in the sun s chromosphere that did not exactiy coincide with the D-lines of sodium. This line was attributed to a new element which was named helium, from the Greek hellos, the sun. In 1891 an inert gas isolated from the mineral uranite showed unusual spectral lines. In 1895 a similar gas was found in cleveite, another uranium mineral. This prominent yellow spectral line was then identified as that of helium, which to that time had been thought to exist only on the sun. In 1905 it was found that natural gas from a well near Dexter, Kansas, contained nearly 2% helium (see Gas, natural). 

As evidence that this is so, consider that the element helium was detected in the sun before it was found on earth Though oxygen contains 0.2% of the oxygen-18 isotope on earth, it, too, was first detected in a solar spectrum. Two... 

An element is a substance that cannot be broken down into simpler substances by ordinary means. A few more than 100 elements and many combinations of these elements—compounds or mixtures—account for all the materials of the world. Exploration of the moon has provided direct evidence that the earth s satellite is not composed of any different elements than those on earth. Indirect evidence, in the form of light received from the sun and stars, confirms the fact that the same elements make up the entire universe. Helium, from the Greek Helios, meaning sun, was discovered in the sun by the characteristic light it emits, before it was discovered on earth. 

The planet Jupiter occupies a special position in the solar system. It is the largest and heaviest planet, with a mass of 1/1,047 that of the sun. Jupiter consists almost solely of hydrogen and helium with a ratio similar to that found in the sun itself He H 1 10. Small amounts of some heavier elements are present, such as B, N, P, S, C and Ge. The density of Jupiter has been calculated as 1,300 kg/m3. Its atmosphere can be divided into three zones (starting from the outermost) ... 

Unfortunately, the Schrodinger equation for multi-electron atoms and, for that matter, all molecules cannot be solved exactly and does not lead to an analogous expression to Equation 4.5 for the quantised energy levels. Even for simple atoms such as sodium the number of interactions between the particles increases rapidly. Sodium contains 11 electrons and so the correct quantum mechanical description of the atom has to include 11 nucleus-electron interactions, 55 electron-electron repulsion interactions and the correct description of the kinetic energy of the nucleus and the electrons - a further 12 terms in the Hamiltonian. The analysis of many-electron atomic spectra is complicated and beyond the scope of this book, but it was one such analysis performed by Sir Norman Lockyer that led to the discovery of helium on the Sun before it was discovered on the Earth. 

Helium - the atomic number is 2 and the chemical symbol is He. The name derives from the Greek helios for sun . The element was discovered by spectroscopy during a solar eclipse in the sun s chromosphere by the French astronomer Pierre-Jules-Cesar Janssen in 1868. It was independently discovered and named helium by the English astronomer Joseph Norman Lockyer. It was thought to be only a solar constituent until it was later found to be identical to the helium in the uranium ore cleveite by the Scottish chemist William Ramsay in 1895. Ramsay originally called his gas krypton, until it was identified as helium. The Swedish chemists Per Theodore Cleve and Nils Abraham Langet independently found helium in cleveite at about the same time. 

In 1904, Sir William Ramsay was the first Briton to be awarded the Nobel Prize for Chemistry. He was educated at Glasgow Academy and Glasgow University and the prize was in recognition of the work he had carried out with others to discover the noble gases. Helium was discovered in the Sun before it was ever found on planet Earth. How do you think it was possible to do this ... 

Helium is also the result of fusion reactions wherein the nuclei of heavy hydrogen are fused to form atoms of hehum. The result is the release of great amounts of energy. Fusion is the physical or nuclear reaction (not chemical reaction) that takes place in the sun and in thermonuclear weapons (e.g., the hydrogen bomb). 

Hydrogen fusion via either the proton-proton chain or the CNO cycle in the centre of stars comes to an end when most of the hydrogen has been transformed into helium. Helium fusion produces two elements essential to life, namely carbon and oxygen. In fact, carbon constitutes 18% of our bodies, and oxygen 65%, whilst the fractions of these same elements in solar material are just 0.39% and 0.85%, respectively. Only hydrogen and helium are more abundant in the Sun. 

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