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.
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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
Go to topicThis animation shows an artist's representation of the huge collision in the Bullet Cluster.
From here on Earth, we are able to see the Bullet Cluster across our line of sight, and hence the process of merger can be seen clearly. In Abell 576, where two galaxy clusters are merging head on, in our line of sight, it is harder to disentangle.
During the collision the hot gas (shown in red) in each cluster is slowed and distorted by a drag force, similar to air resistance. A bullet-shaped cloud of gas forms in one of the clusters.