Janssen, Pierre

Arestal (Janssen-Cilag) Diaretyl (RPR Cooper) Dyspagon (Pierre Fabre)... 

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. 

French astronomer Pierre Janssen First observed on the sun, this inert and noble gas forms no known stable compounds. 

In the year 1868 the French astronomer Pierre-Jules-Cesar Janssen (43, 44) went to India to observe a total eclipse of the sun and to make... 

Pierre-Jules-Cesar Janssen,0 1824-1907. French astronomer who directed many astronomical expeditions. Member of the French Institute and of the Bureau of Longitude. In 1868 he observed in the sun s chromosphere a yellow line, Da, which is now known to belong to the element helium. He was the director of the astrophysical observatory at Meudon. 

Yes, the French astronomer Pierre Janssen detected a yellow line in the solar spectrum of light coming from the edge of the Sun. It was during an eclipse in 1868. ... 

Because helium forms no compounds and is almost absent in the Earth s atmosphere, it was unknown for a long time. The first clue leading to its discovery was an unidentified yellow emission line in the solar chromospheric spectrum observed by French astronomer Pierre Janssen during an eclipse of the Sun in 1868. Lockyer named the unknown element helium for the Greek sun god, helios. Subsequendy it was discovered to be rather abundant in radioactive rocks, where it is trapped after emission from uranium series alpha decays. Ramsay and Soddy showed that the alpha rays were helium atoms whose electrons had been stripped away. In his biography of Lord Rutherford, A. S. Eve wrote ... 

Helium was first discovered not on Earth, but in the sun. In 1868 French astronomer Pierre Janssen (1824-1907) studied light from the sun during a solar eclipse. He found proof that a new element existed in the sun. He called the element helium. 

An Element on the Sun This principle led to the discovery of helium. In 1868, Pierre Janssen visited India in order to observe a full eclipse of the sun. A solar eclipse occurs when the Moon comes between the sun and Earth. The Moon blocks nearly all of the sun s light. All that remains is a thin outer circle (corona) of sunlight around the dark Moon. Solar eclipses provide scientists with an unusual chance to study the sun. 

Pierre Janssen and Norman Lockyer discover helium in the spectrum of the sun. 

Pierre Janssen, studies the spectra of a solar eclipse and finds evidence of a new element. Edward Frankland, an English chemist, and Joseph Lockyer, an English astronomer, suggest the name helium. 

The name comes from the Greek helios, meaning the sun. It was first detected by its spectra by Pierre-Jules-Cesar Janssen (1824-1907) in the... 

One of the earliest and most famous examples of the use of spectrometry to study the solar system occurred in 1868. While observing a solar eclipse in India, the French astronomer Pierre Janssen (1824-1907) found a new spectral line in sunlight very close to one found in the spectrum of sodium. Janssen was able to show, however, that the new yellow light was different from the sodium line. Indeed, it was a spectral line that had never before been observed on Earth. Janssen hypothesized that the presence of the line could be explained only if the Sun s atmosphere contained an element that had not yet been discovered on Earth. The British astronomer Sir Norman Lockyer (1836-1920) later suggested the name helium for the element, a name based on the Greek word for "sun," helios. It was almost 30 years later that Janssen s bold hypothesis was confirmed. In 1895, the British chemist and physicist Sir William Ramsay (1852-1916) first detected helium on Earth, during a series of experiments on an ore of uranium called clevite. 

The first attempts to study the Martian atmosphere by spectroscopic means were carried out in 1867, by the French astronomer hy Pierre Jules Janssen (1824-1907) and the English astronomer Sir William Huggins (1824-1910). The two scientists were unable to detect the presence of any elements or compounds in their research, however. More than four decades later, the American astronomer W. W. Campbell (1862-1938) searched the Martian atmosphere for water vapor and, failing to find any, concluded that the planet had a much thinner atmosphere than that of Earth, a hypothesis that proved to be correct. 

Here is part of the spectrum which the French astronomer Pierre Jules C sar Janssen observed. 

In 1868 the French physicist Pierre Janssen detected a new dark line in the solar emission spectrum that did not match the emission lines of known elements. The name helium (from the Greek helios, meaning the sun) was given to the element responsible for the absorption line. Twenty-seven years later, helium was discovered on Earth by the British chemist William Ramsay in a mineral of uranium. On Earth, the only source of helium is through radioactive decay processes—a particles emitted during nuclear decay are eventually converted to helium atoms. 

Spectroscopy was also used to look at the light from the Sun and stars. Scientists Joseph Lockyer and Pierre Janssen did this. In 1868, they looked at the Sun s spectrum during an eclipse. They found lines for an element they did not know. The new element was called helium. Later, scientists found helium on Earth, too. 

Helium 1868 Pierre Janssen (Prance) Joseph Norman Eockyer ... 

As mentioned, argon was the first noble gas to be discovered, but helium was in fact known 26 years before the discovery of argon. The French astronomer Pierre J. C. Janssen (1824-1907) studied a total solar eclipse in India in 1868. A yeUow line D3, not coincident with sodium s doublet, was observed. Neither did the Hne emanate from hydrogen or any other known element, as was proved by the British astronomer Sir Norman Lockyer (1836-1920). Thus there was an element in the sun that was not known on earth. It was named helium due to its origin in the sun. Many spectrum analysts did not accept the new solar element. However, in 1876, John W. Draper, the first president of the American Chemical Society, made an inspired statement [51.1] ... 

---