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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This is an artist’s impression of a Jupiter-sized planet passing in front of its parent star.
Such events are called transits. When the planet transits the star, the star’s apparent brightness drops by a few percent for a short period. Through this technique, astronomers can search for planets across the galaxy by measuring periodic changes in a star’s luminosity.
The first class of exoplanets found by this technique are the so-called “hot Jupiters,” which are so close to their stars they complete an orbit within days, or even hours.