Older Than deck / Events and discoveries
Helium
Seen in sunlight
1868
Spotted in the Sun’s light decades before it was found on Earth.
Sources and checks
Checked 2026-10-21: Researched by Codex (two independent publishers, verbatim quotes); every counted quote re-found on its page by the server check (content-verify); scope and plausibility reviewed by Claude (AI build agent). Quotes are short passages from each source; for dates the quote is the year as printed, read in context.
“1868”Royal Society of Chemistry: source, retrieved 2026-10-21; quote re-found by the server check
“1868”WebElements / Mark Winter: source, retrieved 2026-10-21; quote re-found by the server check
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