Researched
Spectroscopy
Bunsen and Kirchhoff (1859) show that every element glows in its own colours: light becomes a chemical fingerprint, even from stars.
Open in the interactive tree →Joseph Fraunhofer mapped dark lines in sunlight in 1814; in 1859-60 Robert Bunsen and Gustav Kirchhoff in Heidelberg showed that each element emits and absorbs light at its own wavelengths. They found caesium and rubidium this way, and astronomers saw helium in the Sun's spectrum in 1868, decades before it was found on Earth. The puzzle of atomic spectral lines also drove the invention of quantum theory.
Prerequisites
- Glassmaking & Glassblowing~50 BC
- Wave Optics (Young, Fresnel)1801
- Atomic Theory (Dalton)1808
- Fraunhofer: Lines & Gratings1814Kirchhoff and Bunsen explained the dark lines Fraunhofer had mapped
Unlocks
- Periodic Table of Elements1869Spectral analysis found new elements (caesium, rubidium, gallium) that fill the table
- Chromatography1903
- Quantum Mechanics1925Atomic spectral lines were the puzzle quantum theory had to solve
- Expansion & Big Bang1929Galaxy redshifts are measured from shifted spectral lines
- NMR Spectroscopy1946
- Exoplanet discovery199551 Peg b was found from Doppler shifts in its star's spectrum