![\"Blobs](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/01\/Comparison_and_contours_vGL.jpg\")
<\/p>\nHow scientists constructed this dark matter map<\/p>\n
To indirectly detect large sources of dark matter across this particular patch of sky, scientists used a technique called gravitational lensing.<\/p>\n
A massive cosmic object like a galaxy or galaxy cluster can cause light from a more distant source to bend and appear distorted. In a phenomenon called \u201cstrong lensing,\u201d light from the distant source is brightened, such that it appears magnified or even warped around it like a ring. But in this case, researchers were looking for more subtle \u201cweak lensing,\u201d in which galaxy shapes are ever so slightly distorted or displaced because dark matter disrupts the trajectory of light. A large number of galaxies is necessary to calculate the amount of dark matter responsible for the weak lensing effect.<\/p>\n
\u201cThe galaxies, or whatever we’re looking at, get bent into these characteristic shapes, like a funhouse mirror, or like looking through a kitchen a bathroom window,\u201d Massey says. \u201cAnd we work out how much dark matter there is by figuring out how it distorted the shapes of these background galaxies.\u201d<\/p>\n
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Here are the Hubble (left) and Webb (right) maps of dark matter in the COSMOS field. The overlaid contour lines\u00a0mark regions of equal dark-matter density.<\/p>\n
Dr Gavin Leroy\/Professor Richard Massey\/COSMOS-Webb collaboration<\/p>\n
Measuring dark matter indirectly in this way is akin to observing the trees and inferring that wind causes the movement of leaves and branches, Massey says. That\u2019s no small feat when it comes to calculating subtle changes in hundreds of thousands of galaxies. Researchers looked at the same patch of sky with Webb for 255 hours, representing the biggest survey from the first year of the telescope\u2019s scientific operations, which began in 2022.<\/p>\n
More than just this map<\/p>\n