How an astronomer discovered the link from the stars to the properties light itself.
William Herschel was born in Hanover, part of the Holy Roman Empire on the 15th of November 1738. Initially he started his career in a military band, however at the age of 19 he migrated to Great Britain after the Hanoverian Guards were defeated by the French in the Seven years war.
Upon arrival to England he played music and composed 24 symphonies, which are still heard today. However, his true fame lies in astronomy. Reading into natural philosophy and engaging with the 18th century Philomath’s of the time, his intellectual prowess grew rapidly.
He read books by Robert Smith, William Emerson and Sir Isaac Newton which prompted him to build his first telescope due to the influence they had on him, a replica of which is in his museum in Bath, England. He took to looking at the stars in 1773 and by 1774 he discovered the rings of Saturn and the Great Orion Nebula. The first ever written account of the rings of Saturn was by Herschel, which he described as the planet having “ears”. Later in his astronomy career he also discovered 4 moons as well as Uranus.
Later in his life after delving into astronomy further in 1800 he was testing filters for the sun so that he could observe sunspots through a telescope. Taken from his past interest in Newtons works, he was using a prism to split a beam of light from the sun. Holding a thermometer out from the red end of the spectrum he discovered that there was an increase in temperature in comparison to the visible light spectrum. He had discovered infrared radiation from the sun, and gave birth to the study of spectrometry and wavelengths outside of the visible spectrum. He initially explained this phenomenon as “calorific rays” from the Latin heat.
This discovery boosted further scientists to analyse the light spectrum which had stagnated for a time. This study of invisible light waves has given us a huge understanding of light, from gamma rays to the commonly used X-ray in hospitals. Without Herschel’s push in the study of the light spectrum, it’s easy to imagine that spectrometry would have slowed and we would be behind where we are today.
In the study of flame photometers, his work is referenced in further works from other scientists touched on in our previous blog post. We will continue down this track and give a more in depth look at the forefathers of the BWB Flame Photometer.