Astronomy Today


What chemical element was first discovered by astronomical spectroscopy?

A major scientific triumph in the early history of astronomical spectroscopy was the discovery of the element helium. Since helium is lighter than air, it leaves Earth’s atmosphere unless it is carefully contained. And because of its atomic structure, it is an inert gas and almost never participates in chemical reactions here on Earth. When astronomers first used spectroscopy to study the Sun, though, there were features in the solar spectrum that had never been observed in spectra of terrestrial matter. Scientists realized that a new element had been discovered, and named this new element helium after Helios, the ancient Greek name for the Sun. Eventually, we learned how to gather and use helium here on Earth. Today, we also know that helium is the second most abundant element in the universe, comprising one-quarter of all the atomic mass in the cosmos.


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