Spectroscopy is a technique used to analyse light by breaking it apart into its component colours with a prism or grating and studying the resulting pattern, which is known as a spectrum. Dark absorption and bright emission lines that interrupt the rainbow of colours from the split-apart light allow scientists to 'fingerprint' the light's source.
By studying a star's spectrum, scientists can work out its chemical make-up and temperature. Spectroscopy also allows astronomers to work out the relative velocities of galaxies and supernovae by measuring something called red shift.
Image: A spectrum of the Sun (credit: Physics dept., Imperial College/SPL)
A powerful technique helps scientists 'fingerprint' starlight.
Jem Stansfield shows there's more to white light than meets the eye.
There's more to white light than meets the eye - in this extra web film Jem uses an old CD to compare the spectrums of different household lights. Try it yourself at home.
Dallas Cambell has a neat way of detecting the infrared in sunlight.
If infrared light is invisible, how can we be sure it's present in sunlight? Dallas has a neat way of finding out with just a prism and a thermometer.
Nineteenth century astronomers split the Sun's light to see more of its structures.
By splitting the light of the Sun into its component colours with a technique called spectroscopy, early astronomers saw more of the Sun's features. They also worked out what chemical elements form the Sun.
George Hale discovers sunspots' magnetic origins.
Through careful spectrographic study, early 20th century American astronomer George Hale discovered that sunspots are caused by distortions in the Sun's powerful magnetic field.
Prof Brian Cox studies the colour of stars to understand how the Universe began.
Prof Brian Cox explains how we can understand the origins of the Universe through differing wavelengths of light emitted by stars.
Spectroscopy /spɛkˈtrɒskəpi/ is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, by a prism. Later the concept was expanded greatly to comprise any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is often represented by a spectrum, a plot of the response of interest as a function of wavelength or frequency.
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