No trace of dark matter halos

According to the standard model of cosmology, the vast majority of galaxies are surrounded by a halo of dark matter particles. This halo is invisible, but its mass exerts a strong gravitational pull on galaxies in the vicinity. ...

Hey Siri: How much does this galaxy cluster weigh?

It's been nearly a century since astronomer Fritz Zwicky first calculated the mass of the Coma Cluster, a dense collection of almost 1,000 galaxies located in the nearby universe. But estimating the mass of something so huge ...

Webb Telescope: What will scientists learn?

The James Webb Space Telescope's first images aren't just breathtaking—they contain a wealth of scientific insights and clues that researchers are eager to pursue.

Astronomers are helping find elusive atoms across the universe

Astronomers at the University of Toronto have spotted some of the most elusive stuff in our universe by taking a deep look at the cosmic web, the network of filaments and knots that trace the large-scale distribution of galaxies.

Image: Hubble captures a galactic menagerie

The NASA/ESA Hubble Space Telescope captured this massive galaxy cluster, called Abell 1351, with its Wide Field Camera 3 and Advanced Camera for Surveys. Abell 1351 lies in the constellation Ursa Major in the northern hemisphere.

A massive galaxy supercluster in the early universe

The structure of the universe is often described as being a cosmic web of filaments, nodes, and voids, with the nodes being clusters of galaxies, the largest gravitationally bound objects known. These nodes are thought to ...

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Galaxy groups and clusters

Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation. They form the densest part of the large scale structure of the universe. In models for the gravitational formation of structure with cold dark matter, the smallest structures collapse first and eventually build the largest structures, clusters of galaxies. Clusters are then formed relatively recently between 10 billion years ago and now. Groups and clusters may contain from ten to thousands of galaxies. The clusters themselves are often associated with larger groups called superclusters.

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