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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Artistic view of electrons, responsible for aurora, spiralling down magnetic field lines. The U-shaped potential structure illustrates the region where electrons get accelerated on their way down to the upper atmosphere. Here they are stopped by collisions with neutral atoms and molecules, primarily oxygen and nitrogen, at altitudes of a few hundreds kilometres down to 80 kilometres. Each collision transfers part of the electron energy to these atmospheric particles. In turn, they get rid of this energy excess by emitting visible emissions in specific wavelength (or colours) such as green (oxygen) or purple (nitrogen).