The Nancy Grace Roman Space Telescope (NGRST) is on its way to its station at the Sun–Earth L2 point, where it will begin its projected 5-year mission. It has several goals, including measuring dark energy's effect on the Universe, the growth of structure, and general relativity's consistency over time. Gravitational lensing plays a big role in its work.

There are two kinds of gravitational lensing, strong and weak. In strong gravitational lensing, a massive foreground object like a galaxy cluster lines up with a background object and produces magnified and distorted images of the background object, making the background object open to observations. It can produce Einstein rings , arcs, and multiple images of the background object.

These distortions let scientists measure the mass of the foreground galaxies. Since visible matter isn't enough to cause the distortion on its own, scientists can do some fancy math to calculate the amount of dark matter that must be present.…