The discovery of helium by Pierre Janssen marked a pivotal moment in the study of astronomy and chemistry. During a total solar eclipse in Guntur, India, on August 18, 1868, he was engaged in observing the solar spectrum. Janssen utilized a spectroscope to break down sunlight into its component colors, allowing for the examination of the light emitted from the sun. As he meticulously studied the spectrum, he noticed a unique spectral line, which signified the presence of an unknown element. This line was located at a wavelength of 587.49 nm and was distinct from the spectral lines of all known substances at that time.

Intrigued by his findings, Janssen shared his observations with the scientific community, and his work prompted further investigations into the element he discovered. Soon after, English astronomer Sir William Huggins also observed this same spectral line while conducting similar studies. The two men independently confirmed the existence of this new element, which was eventually named helium, deriving its name from 'Helios,' the Greek god of the sun. This discovery not only introduced helium as a new element but also underscored the importance of spectral analysis in identifying substances in distant celestial bodies.

In the subsequent years, helium was also discovered on Earth, cementing its status as the second most abundant element in the universe, after hydrogen. This finding led to further research and exploration of elements beyond our planet, contributing to the burgeoning field of astrophysics and the study of cosmic elements. The methodologies developed during Janssen's work paved the way for future astronomers and scientists to explore stellar compositions and the nature of the universe more broadly.