 channel for physics. Please subscribe my channel. Hello everyone and welcome back to another episode of physics partner. Today we are going to discuss a very very interesting topic spectroscopy. Spectroscopy is used as a tool for starting the structure of atoms and molecules. The large number of wavelength emitted by these systems make it possible to investigate their structures in detail including the electronic configuration of ground and various excited states. Spectroscopy also provides a precise analytical method for finding the constituents in material having unknown chemical composition. But today's video is about astronomical astroscopy. Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation including visible light which radiates from sun and other hot celestial objects. Spectroscopy can be used to drive many properties of distant stars and galaxies such as their chemical compositions, temperature, density, mass, distance, luminosity and relative motion using Doppler shift measurements. How can we do that? Spectroscopy is one of an astronomer favorite tools to help understand the universe. Stars and galaxies are just too far away to be analyzed in the laboratory. Fortunately very important information about these distance bodies is written in the light we detect with a telescope. Let's have an example here. You can see the sample of hydrogen is here and the wavelength observed from hydrogen is 656 nanometer. In case of nitrogen it is 747 nanometers and in case of helium it is 782 nanometer. Similarly neon will give you 784 nanometer and argon will give us 772 nanometer. We have to understand the band first. If you look the band carefully, same like a rainbow, it's one an is towards red and other it's towards blue. In the spectrum the blue light means it is high frequency, contain high energy and a small wavelength whereas the red side will show the lowest energy means lowest frequency and largest wavelength. In the spectrum if you move from blue to red you can observe that the wavelength is going to be increases. It means automatically frequency is going to be decreased and energy level is also going to be decreased as wavelength and frequency are reciprocal each other. So the astronomer can check the light spectrum from different star and they can find out the composition of the star with the help of the color. For example if the color is red and and wavelength is 782 nanometers it means this star is heavily composed on helium. Similarly if you find 772 nanometers wavelength so it means it comprises on argon. With the help of a spectroscope astronomers are able to find the composition of different stars. They can receive the light and with the help of a spectroscope they can find the composition of any star. But light is not an open book to be read. Light must be split into different colors or wavelength in the same way that rain droplets disperse the light to form a rainbow. Newton called this rainbow color the spectrum the Latin word from appearance. The first astronomical application of spectroscopy was in the analysis of sunlight by Fronhofer and Kirchhoff in the early 19th century. I'm going to add some articles in the description if you're interested to know more advanced about spectroscopy. I hope you enjoyed this video. It was really very interesting topic. Thank you very much for your listening. Take care of yourself. See you in the next video. Goodbye.