Helium

Did you know that the discovery of helium's existence preceded its discovery as an element on Earth?

In 1868 Pierre J. C. Janssen travelled to India to study a total eclipse and he observed a new line in the corona spectrum, which meant an unknown element was present on the sun. (He named it helium thinking it would be a metal.) The same year two Britons, astronomer Norman Lockyer and chemist Edward Frankland, confirmed Janssen's observation when they viewed the sun's spectrum through London smog. The belief was that this new element, clearly abundant on the sun, would not be found on Earth. 

John Emsley explores Helium...