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
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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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This artist’s impression shows the ‘light curve’ produced by a star passing behind Titan, Saturn’s biggest moon.
When such occultation events take place, the light from the star is blocked out. Because Titan has a thick atmosphere, the light does not ‘turn off’ straight away. Instead, it drops gradually as the blankets of atmosphere slide in front of the star, as the light-curve drawn here shows. The way the light drops tells astronomers about the atmosphere of Titan.
The peak at the centre of the light curve represents the bright flash occurring at the very middle of the occultation. This is due to the fact that Titan’s atmosphere acts as a lens, making the light emitted by the star passing behind converge into a focal point and produce the flash.