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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At first glance, a bright blue crescent immediately jumps out of this NASA/ESA Hubble Space Telescope image: is it a bird? A plane? Evidence of extraterrestrial life? No — it’s a galaxy.
The shape of this galaxy admittedly appears to be somewhat bizarre, so confusion would be forgiven. This is due to a cosmic phenomenon called gravitational lensing. In this image, the gravitational influence of a massive galaxy cluster (called SDSS J1110+6459) is causing its surroundings spacetime to bend and warp, affecting the passage of any nearby light. This cluster to the lower left of the blue streak; a few more signs of lensing (streaks, blobs, curved lines, distorted shapes) can be seen dotted around this area.
This image also features a rare and interesting type of galaxy called a jellyfish galaxy, visible just right next to the cluster and apparently dripping bright blue material. These are galaxies that lose gas via a process called galactic ram pressure stripping, where the drag caused by the galaxy moving through space causes gas to be stripped away.