How astronomers use gravity as the ultimate camera lens

The Hubble Space Telescope has an incredible camera system in its own right, but thanks to a phenomenon called the gravitational lens, it can capture images far beyond what human technology and optical science currently allow.

As indicated through Fstoppers, NASA explains this extreme gravity can create some interesting visual effects that can be observed with the Hubble Space Telescope. Einstein predicted that mass can distort space, and his theory of relativity describes how concentrations of mass distort the space around them. A gravitational lens can occur when a huge amount of matter, such as a large cluster of galaxies, creates a gravitational field that distorts and amplifies light from distant galaxies behind it, but in the same line of sight.

Basically, gravity distorts space in such a way that it creates an “optic” that channels light into Hubble and gives it the ability to see galaxies that are normally too far apart to be studied with current technology and physical telescopes. . NASA describes it as looking through a giant magnifying glass.

“As Hubble looks into these galaxy fields, we sometimes see clusters of galaxies. These are galaxies that are kept close to each other by their mutual gravity, ”says Dr. Jennifer Wiseman, senior scientist on the project at NASA. “These clusters are massive agglomerations. There is so much mass that they have a real observable impact on space-time itself.

Thanks to Hubble, scientists were able to see distortions in space around clusters of galaxies.

“The way we see it is when light from a background galaxy moves through or around that cluster of galaxies, due to this gravitational lensing effect,” Wiseman continues.

The photo below is a cluster of galaxies called the Abell 370 which contains what NASA describes as “an astonishing assortment of several hundred galaxies linked together by the mutual attraction of gravity.” This photo is only made possible thanks to the gravitational lens.

“More complex gravitational lenses occur in observations of massive clusters of galaxies. Although the distribution of matter in a galaxy cluster usually has a center, it is never circularly symmetrical and can be considerably lumpy. Background galaxies are crystallized by the cluster, and their images often appear as short, thin “lens arcs” around the cluster’s periphery, “NASA elaborates.

“When we look at some of these warped arcs, we can see more detail than we could ever have seen without the gravitational lens, nature’s nudge,” says Wiseman.

Wiseman says the gravitational lens allowed them to use Hubble in unexpected ways. Essentially treating gravity like nature’s magnifying lens, what it can capture teaches them more about distant galaxies than they could ever have seen without the phenomenon.

“It also tells us how dark matter is distributed in these clusters, because it turns out that most of the mass that distorts space and these galaxy clusters is made up of this invisible dark matter, not visible stars. in galaxies, and we can “I can’t see dark matter,” Wiseman says. “But by seeing how this background light is distorted, we can sort of map where this dark matter is.”