how is gravitational lensing related to dark matter. The majority of the mass and the structure of the universe are made up of dark matter, an invisible form of matter. Normal matter (gas and dust) is pulled together by the gravity of dark matter, which then grows into stars and galaxies. Even though astronomers cannot directly observe dark matter, their observations of the way in which the gravity of large galaxy clusters containing dark matter warps the light of distant galaxies behind the cluster allows them to infer its presence. Gravitational lensing is the term for this effect.
Hubble’s exceptional resolution has allowed astronomers to use gravitational lensing to map the distribution of dark matter across the cosmos. Dark matter and ordinary matter coexist in large groups of galaxies. Astronomers can figure out where the densest concentrations of matter are by observing the regions surrounding massive clusters of galaxies and identifying warped background galaxies. The location and properties of the lensing material, both visible and invisible, are revealed by mathematical models of these results (dark). Around five times as much dark matter as ordinary matter seems to permeate the cosmos, and everything appears to be connected by a vast web of dark matter filaments that have expanded over time. Huge visible structures, such as clusters of galaxies, can be found at the points where these filaments intersect.
The enormous galaxy cluster Cl 0024+17 (ZwCl 0024+1652) is shown in two Hubble Space Telescope images. On the left is the visible-light picture, where some peculiar blue arcs can be seen among the more typical yellowish galaxies. These are enlarged, warped pictures of galaxies far beyond the cluster’s visible edge. With gravitational lensing, the enormous gravity of the cluster distorts and amplifies their light. Invisible material called dark matter is mathematically required to account for the nature and placement of the observed gravitationally lensed galaxies, so a blue shading has been added to the right to indicate its location.
