Using gravitational insolation, the Euclid mission looks into the dark world, maps the distribution of dark matter and studies the expansion of the universe by observing billions of galaxies
The European Space Agency's Euclid mission is scanning the sky to discover the composition and evolution of the dark world. But how can Euclid observe something invisible? This video explains the phenomenon of light bending that helps scientists map dark matter throughout the cosmos.
Using Euclid's advanced imaging, the video demonstrates how filaments of dark matter subtly distort the shape of galaxies. As light from distant galaxies travels to us, it is bent and distorted by concentrations of matter along the way. This phenomenon, known as gravitational priming, occurs because both "normal" matter and dark matter act as a cosmic magnifying glass.
The scientists classify gravitational pull into two types: strong and weak. In strong dust, the distortion of galaxies or light sources in the background is dramatic, creating phenomena such as rainbows, double entanglements or Einstein rings. Weak dusting, on the other hand, causes only a slight stretching or displacement of background sources, which can only be detected through statistical analysis of a large number of galaxies.
The farther you look, the more pronounced the distortions due to weak gravitational repulsion, because there are more structures of dark matter acting as lenses between us and the light source.
Euclid will measure the distorted shapes of billions of galaxies over 10 billion years of cosmic history, producing a three-dimensional view of the distribution of dark matter in the universe. This will shed light on the nature of this mysterious component.
From the map of the distribution of galaxies over cosmic time we will also learn about dark energy, which affects the expansion speed of the universe. By mapping the large-scale structure of the universe in unprecedented detail, Euclid will allow scientists to track how the expansion changes over time.
The huge mosaic published by the Euclid Space Telescope on October 15, 2024
The first part of Euclid's map, a massive 208-gigapixel mosaic, was unveiled at the International Astronautical Conference. This mosaic includes 260 observations made between March 25 and April 8, 2024. In just two weeks, the telescope was able to capture 132 square degrees of the southern sky in clarity Magnificent - an area more than 500 times the size of the full moon. This mosaic makes up only XNUMX percent of the broad survey that the Euclid mission will complete in its six-year mission.
This first part of the map already contains around 100 million sources: stars in our Milky Way and other galaxies. About 14 million of these galaxies can be used to study the hidden influence of dark matter and dark energy on the universe.
"This amazing image is the first part of a map that in six years will reveal more than a third of the sky. It is only one percent of the map, yet it is full of a variety of sources that will help scientists discover new ways to describe the universe," says Valeria Petorino, the Euclid project scientist at the space agency the European.
The spacecraft's sensitive cameras captured a huge number of objects in great detail. When the mosaic is greatly enlarged (this image is 600 times enlarged compared to the full view), one can still clearly see the complex structure of a spiral galaxy.
A special phenomenon seen in the mosaic is dim clouds between the stars in our galaxy, visible in light blue against the black background of space. They are a mixture of gas and dust, and are also called "galactic cirrus" because they look like cirrus clouds. Euclid can see these clouds with its super-sensitive visible light camera because they reflect optical light from the Milky Way.
The area of the mosaic in this image is enlarged 600 times compared to the large mosaic. One spiral galaxy, ESO 364-G036, is seen in great detail, 420 million light-years away. This image shows 0.0003% of the original 208-gigapixel image, which is 1/330,000 of the area of the main Euclid mosaic.
Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi
This area is magnified 150 times. On the left is an interaction between two galaxies, ESO 364-G035 and G036, 420 million light years away. On the right we see the galaxy cluster but 338, 678 million light years from us.
Credit: ESA/Euclid/Euclid Consortium/NASA, CEA Paris-Saclay, image processing by J.-C. Cuillandre, E. Bertin, G. Anselmi
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