Background

In 1868, during a solar eclipse, a man named Pierre Janseen discovered a new element on the Sun that had never been seen before on Earth with the use of a spectroscope.  He named it helium from the Greek word helios which means "sun".  Scientists searched 30 years for helium on Earth until, in 1895 Sir William Ramsey discovered helium in a mineral of uranium.  Two lesser known scientists who discovered helium at around the same time were Per Teodor Cleve and Nils Abraham Langlet, who discovered helium in a mineral called cleveite.  Ernest Rutherford, an English physicist discovered that alpha particles are helium atoms without their electrons in 1907.  This explains why the helium was in a mineral of uranium, it was given off as alpha radioactivity.