Talk:Helium

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The helium article should be edited in several places to correct the history of the observation of the line near D3. The following text should be removed in its entirety: "Helium was first detected as an unknown, yellow spectral line signature in sunlight during a solar eclipse in 1868 by Georges Rayet,[14] Captain C. T. Haig,[15] Norman R. Pogson,[16] and Lieutenant John Herschel,[17] and was subsequently confirmed by French astronomer Jules Janssen.[18] Janssen is often jointly credited with detecting the element, along with Norman Lockyer. Janssen recorded the helium spectral line during the solar eclipse of 1868, while Lockyer observed it from Britain. "

Justification for above edit: Rayet's report in no way can be interpreted to conclude that he saw a new line near the D line; see the quotation given in ref [14]. Haig's report is relatively vague, and the colors given do not correspond to that of the D3 line (which is yellow). Pogson's unpublished report is ambiguous and non-quantitative; he could not rule out that the line he saw was the D line itself. And Herschel concluded that the line he saw WAS the D line, not a new line. Ascribing any portion of the discovery of the line Lockyer called D3 to any of these scientists is at best wishful thinking.

Also, the following sentences should be removed: "The line was detected by French astronomer Jules Janssen during a total solar eclipse in Guntur, India.[26][27] This line was initially assumed to be sodium. " Janssen did NOT report this line in his 1868 letter to the French Academy, and the cited references (Kochhar and Emsley) do not provide compelling evidence to the contrary. For better references, which conclude that Janssen did not see this line before Lockyer, see Launay F (2008) The astronomer Jules Janssen—a globetrotter of celestial physics. Springer, New York, p 45 and Lockyer JN (1868) Spectroscopic observations of the sun—No. II. Phil Trans Roy Soc (London) 159:425–444 as well as the footnote in the Wikipedia text that begins "In his initial report to the French Academy of Sciences" 192.17.85.116 (talk) 16:51, 5 November 2024 (UTC)

Tagged with an expert needed flag as seems quite niche. I don't think anyone uninvolved with chemistry will want to go against the multiple citations here. -OXYLYPSE (talk) 15:19, 25 November 2024 (UTC)

 Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. (3OpenEyes's talk page. Say hi!) | (PS: Have a good day) 19:06, 5 January 2025 (UTC)

I found it interesting some time ago to read that titanium can only be welded in a helium filled room and welders wear space suits with breathing apparatus. It was said to be done in Russia. Titanium is obviously important for aircraft undercarriages, medical parts, and stuff for the military. If someone who has a better idea of this than this layperson, could insert something about it. which links it to our daily lives, I think that would be beneficial. 2001:8003:A070:7F00:C9E9:5E0D:2CB:1210 (talk) 04:50, 2 April 2025 (UTC)

If you have a reference then maybe it could be considered. However, arc welding in He is completely normal and it is not done in space suits! Johnjbarton (talk) 15:37, 12 June 2025 (UTC)

Just as you say: heliarc welding. Cheers, --Pete Tillman (talk) 17:44, 12 June 2025 (UTC)

"The first evidence of helium was observed on August 18, 1868, as a bright yellow line with a wavelength of 587.49 nanometers in the spectrum of the chromosphere of the Sun."

I realize the source explicitly calls the emission lines brilliant, but isn't that the opposite of what should be observed? The Sun's emission spectrum goes dark at 587.49 nm. https://en.wikipedia.org/wiki/Fraunhofer_lines

The source just says he is using a spectroscope. Its not really a tool I'm familiar with, but based on the descriptions I could find it shouldn't be doing anything like inverting the spectrum.

This might just be me getting confused by an ordinary turn of phrase. 199.73.14.23 (talk) 04:27, 12 July 2025 (UTC)

Fraunhofer lines are absorption, so light from deeper in the Sun being absorbed by the atmosphere. The helium line in 1686 was emission, so light from a corona arm goes through the spectrograph. I verified the sources. Johnjbarton (talk) 21:09, 12 July 2025 (UTC)

I'd also add the diproton is an intermediate in the proton-proton chain. ~2025-31258-17 (talk) 23:09, 4 November 2025 (UTC)

I found that there is a new edit (New to me, I have not seen it before) that states that the empirical atomic radius of Helium is 31 pm. Where is the source for this information? Why are there never sources linked to this kind of information? I will attempt to look in the article itself, but I may need another user to help me out here, if not the actual person who added that in. ~2025-31958-91 (talk) 14:57, 23 January 2026 (UTC)

If you look at the bottom of the infobox there is a link "references". That takes you to List of data references for chemical elements. If you click through to Atomic radii of the elements (data page) you will see a table with the referenced values. The ultimate source appears to be this paper, where the 31 pm value (given as 0.31 Å) is in Fig. 3. Double sharp (talk) 15:21, 23 January 2026 (UTC)

Last I knew, there was still disagreement on the radius of the proton. It should not, then, be surprising that the radius of the helium atom is also uncertain. For those that form metallic or covalent crystals, the crystal lattice can be accurately measured. Since helium doesn't form a solid at atmospheric pressure, it is less obvious what to use for a radius. If the accuracy is important to you, then the specific way it is measured should also be important. Gah4 (talk) 17:49, 23 January 2026 (UTC)