How do you get to know the Composition of faraway objects????????

  We all read day to day news, scientists tell that so and so planet is made off....... A question arises in our mind that how do they find out or come to know sitting right on earth, of course spacecrafts can't go to galaxies which are millions of light years away.
  The composition of every object is written in the light that bounces or more precisely gets reflected from the object's surface . Written in the spectrum is the composition of the object . Amazed!?
  Yes when the light hits an object the electrons of the atoms present in the object absorbs some energy casting a black line in the spectrum. these black lines are called Fraunhofer lines named after Joseph von Fraunhofer, who was the inventor the spectroscope. 
   The spectroscope is the combination of prism and a telescope. Prism as it splits the light into its spectrum and telescope because it zooms through the spectrum.
 The order of the back lines is different for different elements as the arrangement of the electron is different in different elements. 
 So thanks to Fraunhofer who has helped us look beyond our reach.

Fraunhofer demonstrating the spectroscope.

Read more on Joseph von Fraunhofer, here

Spectroscope has helped us to not only know about stars and planets but , also galaxies which are totally out of our reach.

Solar spectrum with Fraunhofer lines as it appears visually.

know more on Fraunhofer lines, here
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