Hubble images a gallery of gravitational lenses that NASA's new Roman telescope will follow up

NASA has released a set of Hubble Space Telescope images of galaxies acting as natural magnifying glasses, and says some of them will be observed again by its new Nancy Grace Roman Space Telescope. The gallery, published on November 12, 2026, shows strong gravitational lenses that were first detected with the Dark Energy Spectroscopic Instrument, DESI, at Kitt Peak and then imaged by Hubble. Astronomers want to use them to weigh the foreground galaxies, including the dark matter that cannot be seen directly.

How a lens weighs a galaxy

A gravitational lens forms when a massive foreground galaxy lines up almost exactly with a more distant one. The nearer galaxy's gravity bends, stretches and magnifies the background galaxy's light, so it appears as arcs around the lens. NASA notes that this happens only when the foreground galaxy's mass density reaches a critical point. The degree of distortion tells astronomers how much mass the lens contains and how it is spread out, invisible dark matter included, and the team plans to build lens models from a large and varied sample.

The images may also test a specific idea. The cold dark matter theory predicts many small clumps of dark matter, each between a million and a billion times the mass of the Sun. NASA says Hubble's sharp images and precise models should let researchers spot small imperfections in the lensed arcs that would betray such clumps, which could "potentially prove or dispel a theory about dark matter." For scale, NASA puts the dark matter halo of the Milky Way at around 1.3 trillion solar masses; by our arithmetic, even a billion-solar-mass clump would be less than a tenth of a percent of that.

What the gallery shows

No two of the lenses look alike. Most of the foreground galaxies are ellipticals, which NASA describes as older, denser and more compact, but not all of them are, and researchers can use those differences to trace how the galaxies evolved. Bluish arcs point to young stars in the background galaxies and reddish arcs to older ones.

Two telescopes, two jobs

Hubble sees mainly visible and ultraviolet light, with some infrared, and gives sharp views of single objects. Roman sees mainly infrared, with some visible light, and its field of view is at least 100 times larger than Hubble's, according to NASA's mission page. As a result, NASA says, Hubble gets the better view of an individual lens while Roman will catch more of them; if Roman finds an especially interesting one, researchers may point Hubble at it. Infrared also passes through dust more easily, so Roman could show whether the arcs in panel D close into a fuller ring. By studying the Hubble lenses in detail, researchers intend to build what NASA calls a "super-intelligence tool" to search Roman's images for similar arcs.

The gallery follows a single Hubble lens image NASA published on October 22, in which a foreground elliptical galaxy about 4.5 billion light-years away bends the light of a galaxy about 8 billion light-years away into an arc and a smaller, flipped counterarc. Both releases credit the images to NASA, ESA and X. Huang of the University of San Francisco.

Where Roman stands

Roman launched on August 30, 2026. NASA's commissioning page describes a three-month journey to the Sun-Earth Lagrange point 2, with the observatory commissioned along the way. On October 22, NASA said the observatory had passed its checkout and entered science commissioning, the last stage before science operations. "We've established that the observatory is fully functional," said Julie McEnery, Roman's senior project scientist at NASA Goddard. The team is now running test observations to characterize performance, calibrate the instruments and refine image quality. NASA's posts do not give a date for the start of science operations.