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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Simulated motion of a star in the sky due to parallax, an apparent shift caused by Earth’s yearly motion around the Sun. The parallax has been exaggerated by 10 000 times to make it visible in this animation, which shows the star’s position in the sky for about three and a half years.
Measuring parallaxes is very complex because we observe this apparent motion combined with the true motion of stars through the Galaxy. Astronomers need accurate measurements over more than one year to separate the parallax from the stars’ true movements.
ESA’s Gaia satellite has observed more than one billion stars, measuring their positions, parallaxes and motions across the sky to unprecedented accuracy.