Space Science-Emission spectroscopy

When looking at the graphical representation of light coming from M57 The Ring Nebula, between 1,000 and 3,000 light years from Earth, we see spikes at different wavelengths much like any other spectrum. The brightest two lines at 4959 and 5007 come from oxygen atoms that have had some electrons ripped from them. This gives us a clue as to the conditions in this nebula as this can only happen at temperatures of several thousand degrees celsius and at very low densities of less than 100 atoms per cubic centimetre. From studying such spectra astronomers can get an insight as to the conditions and processes taking place in astronomical objects many light years from Earth.

Emission spectroscopy
When atoms of different elements become hot they give off light of certain colour. When this light is analyzed through a spectroscope we see that it is made up of many different coloured lines. This pattern is called an emission spectrum.and is unique to each element. The emission spectra of hydrogen and helium are shown below and we use these to identify each element just like a bar code identifies the product at the checkout of a supermarket. Most telescopes used by astronomers are connected to spectroscopes and pointed towards astronomical objects collecting the light that comes from them. When you look at light coming from a distant star through a spectroscope you see a unique pattern of coloured lines made up of all the elements present in the star.
Hydrogen Helium Iron
Emission spectra are created when atoms of elements are heated to high temperatures as happens in the core of stars. Read the section on emission and absorption spectroscopy for detail on how they are formed. Below is an emission spectrum formed from light coming from a distant star. If you look at the unique pattern you will notice that it is formed by combining the emission spectrum of hydrogen and the emission spectrum of helium. We therefore know that this far away star is made of helium and hydrogen.

What else can we learn from an emission spectrum? By representing the spectrum as a graph of wavelength versus intensity we can get an idea as to what percentage each element contributes to the mass of the star.

M57 The Ring Nebula
When looking at the graphical representation of light coming from M57 The Ring Nebula, between 1,000 and 3,000 light years from Earth, we see spikes at different wavelengths much like any other spectrum. The brightest two lines at 4959 and 5007 come from oxygen atoms that have had some electrons ripped from them. This gives us a clue as to the conditions in this nebula as this can only happen at temperatures of several thousand degrees celsius and at very low densities of less than 100 atoms per cubic centimetre. From studying such spectra astronomers can get an insight as to the conditions and processes taking place in astronomical objects many light years from Earth.
What is absorption spectroscopy?
An emission spectrum is
The light coming from a distant star can be used to
An emission spectrum can be used to