Helium is the second most abundant element in the universe, only after hydrogen.
Most of us know it as a party trick. Someone inhales it and suddenly sounds like a cartoon character. Helium changes the way sound resonates in the vocal tract, producing that familiar squeaky voice. It is a risky trick, though, because helium displaces the oxygen we need to breathe.
We also know it as the gas that keeps party balloons floating. It is much lighter than air and does not catch fire. Its less visible jobs are rather more demanding. Liquid helium keeps the superconducting magnets in many MRI scanners cold enough to work, at temperatures close to absolute zero. A gas associated with birthday parties also helps doctors look inside our bodies.
That makes reports of helium shortages unsettling. How can we be short of the second most abundant element in the universe?
The answer is that abundance in space does not translate into an accessible supply on Earth. Much of the helium we use accumulated underground over geological time, produced by radioactive decay in rocks. We recover it from suitable gas deposits. Once released into the atmosphere, it becomes uneconomical to collect and can eventually escape into space. It is effectively nonrenewable on human timescales.
Supply disruptions have caused real shortages, but a countdown to the last balloon would be misleading. New production facilities continue to open, while recycling and equipment that needs less helium can reduce demand. The problem is securing and conserving an affordable supply of a gas with some unusually difficult-to-replace uses.
Yet when astronomers first encountered helium, they had no sample to conserve. They had only a clue in sunlight.
On August 18, 1868, a total solar eclipse crossed India. Among those watching was French astronomer Jules Janssen, stationed at Guntur, in present-day Andhra Pradesh. Another observer, Norman Robert Pogson, director of the Madras Observatory, had set up at Masulipatam, now Machilipatnam, near the coast.
They were interested in the prominences: glowing structures that become conspicuous around the Sun’s edge when the Moon covers its brilliant face. A spectroscope allowed observers to separate their light into its component colors. Glowing gases produce bright lines at particular positions in this spread of light. Those patterns can identify the substances producing them.
One yellow line would become famous.
Sodium was already known to produce strong yellow lines. Several eclipse observers associated the yellow light they saw with sodium. Pogson’s report, however, left room for doubt: the line might be close to sodium’s familiar position rather than exactly at it. That small distinction mattered. It was a clue that the Sun might contain something unfamiliar.
A clue, however, is not yet the discovery of an element.
Janssen made another important advance. After the eclipse, he succeeded in observing the bright lines of prominences in ordinary daylight. Astronomers no longer had to wait for the Moon to cover the Sun to study them spectroscopically.
Meanwhile, in England, Norman Lockyer independently developed a way to do the same thing. Janssen’s and Lockyer’s communications were presented to the French Academy of Sciences at the same session in October 1868. Here was an irresistible story: two scientists, working independently in different countries, arriving at the same breakthrough.
But what, exactly, was that breakthrough?
In familiar retellings, their messages announce the discovery of helium. Historian and astrophysicist Biman Nath points out that the communications concerned observing prominences without an eclipse. They did not announce a new chemical element. Over time, two related achievements became folded into one neat discovery story.
Lockyer’s subsequent work helped establish that the troublesome yellow line was distinct from sodium’s. Working with chemist Edward Frankland, he investigated its possible origin. The proposal emerged that it belonged to an unknown element, named helium after Helios, the Greek name for the Sun.
It was an extraordinary suggestion. An element could be recognized in the Sun before anyone had isolated it on Earth.
It was also a suggestion that needed convincing evidence. An unfamiliar line in the spectrum of the hot Sun did not automatically settle the question of a new element. For years, helium remained a substance inferred from light, without a securely identified terrestrial sample.
The decisive earthly confirmation came in 1895. Scottish chemist William Ramsay extracted gas from the uranium-bearing mineral cleveite. Examination of its spectrum revealed the signature associated with solar helium. In Sweden, Per Teodor Cleve and Nils Abraham Langlet independently obtained helium from the mineral as well. The solar element could finally be studied in a laboratory.
Twenty-seven years separated the eclipse observations from that confirmation.
So who discovered helium?
The answer depends partly on what we mean by “discovered.” Recording a spectral line, recognizing that it differs from a known element’s, proposing a new element, and isolating that element are different accomplishments. Janssen, Lockyer, Pogson, Frankland, Ramsay, and the Swedish researchers enter the story at different stages.
Pogson’s place is particularly easy to miss. Nath and historian Wayne Orchiston have argued that his eclipse observations deserve much greater recognition. His report received extremely limited circulation, helping keep his contribution outside the familiar account. Remembering him does not require replacing one pair of heroes with a single new hero. It requires allowing the discovery to have more than one step.
The eclipse had connected observing sites in India with laboratories in Europe. Guntur and Machilipatnam belong in that history alongside the better-known names of the scientists who worked there.
Today, helium lifts balloons and helps make medical imaging possible. Before any of that, it was a yellow line that did not quite fit.
An eclipse in India helped astronomers notice it. Decades of observation and experiment were needed to understand what they had seen.
This article was published in the November 2026 issue of The Sidereal Times, the newsletter of Austin Astronomical Society.
