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 image is an artist's concept of a thermonuclear burst consuming an entire neutron star.
The neutron star (blue sphere) is part of a binary star system, and its neighbouring star (yellow-red sphere) supplies the fuel for the thermonuclear bursts. During solar outbursts or when the orbit brings the stars closer together, gas from the companion star flows toward the neutron star, attracted by its strong gravity. The flow of gas forms a swirling disk around the neutron star, called an accretion disk (multi-coloured swirl around the blue sphere).
Thermonuclear bursts arise as gas moving at close to the speed of light crashes onto the neutron star surface. The gas, pinned to the neutron star by gravity, spreads across the surface. As more and more gas rains down, pressure builds and temperature climbs until there is enough energy for nuclear fusion. This ignites a chain reaction that engulfs the entire neutron star within a second. Bursts last for one to two minutes and can occur several times per hour.