Helium

Do you know how Helium was discovered? It is so interesting!

"An unknown yellow spectral line signature in sunlight was first observed from a solar eclipse in 1868 by French astronomer Jules Janssen. Janssen is jointly credited with the discovery of the element with Norman Lockyer, who observed the same eclipse and was the first to propose that the line was due to a new element which he named helium. In 1903, large reserves of helium were found in the natural gas fields in parts of the United States, which is by far the largest supplier of the gas." *

So, there are several key points here:

1) Each element has its own unique way of reflecting light at different wavelengths of the light's spectrum. That is how in fact scientists observe and identify water, fire, soil,... via remotely sensed data of airplanes, satellites, etc. They have spectral signatures/models of different matter and fit the observed data to those models. In this case, what they saw, did not match the spectrum of any known element. So, they declared discovery of a new element.

2) If it was not for the moon, there would not be a solar eclipse, and we would not learn about the Sun's composition, nor could we discover Helium. Helium was discovered because of the moon!


* http://en.wikipedia.org/wiki/Helium