The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
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Spectroscopy is the technique of splitting received starlight into its different colours using a prism. Exoplanets orbit their stars, when they transit – pass by from our point of view – some of the starlight passes through the planet’s atmosphere. Particles in the atmosphere like water vapour, carbon dioxide, methane and others absorb some of that light. This absorption happens at specific wavelengths of light. By studying at which wavelengths the starlight is absorbed, we can determine what kind of particles are present in the atmosphere. The NASA/ESA/CSA James Webb Space Telescope uses this technique to characterise exoplanets and ESA’s Ariel mission will study the atmospheres of as many as 1000 exoplanets this way. Both missions focus on infrared light because the signatures of molecules are very prominent in those colours.
Acknowledgement: Work performed by ATG under contract for ESA