NASA’s Hubble Space Telescope has spent more than three decades showing us the universe. Now it is helping its newest sibling get a head start.

On November 12, NASA released a gallery of strong gravitational lenses captured by Hubble, a collection meant to lay the groundwork for follow-up observations by the Nancy Grace Roman Space Telescope, which launched in August. Here is what gravitational lenses are, why astronomers care and how this handoff between telescopes works.

What a gravitational lens is

Massive objects bend space, and that bending also bends light. When a huge galaxy sits almost directly between us and a more distant galaxy, its gravity acts like a giant magnifying glass. Light from the background galaxy gets stretched and distorted, often into arcs, smears or even nearly complete rings.

Astronomers call this strong gravitational lensing. It was predicted by Einstein’s general theory of relativity, and today it is one of the most useful tools in cosmology.

What Hubble captured

According to NASA, the new gallery “showcases the diversity of this cosmic phenomenon.” Some lenses show tidy arcs, others show multiple images of the same background galaxy, and each one has a slightly different alignment and shape.

These lenses were first detected by the Dark Energy Spectroscopic Instrument, or DESI, at Kitt Peak National Observatory in Arizona. Hubble then followed up with sharper images, and Roman will take further observations of some of them.

Why astronomers want to study them

Gravitational lenses let scientists weigh galaxies, including the parts they can’t see.

NASA explains that astronomers will use these observations to build lens models that help determine how much mass is in each lensing system’s foreground galaxy. By measuring how much the background galaxy’s light is distorted, researchers can work out both the quantity and the distribution of mass in the foreground galaxy, including its invisible dark matter.

Dark matter doesn’t emit or absorb light, so it can only be detected through its gravity. Lensing is one of the most direct ways to map where it is. NASA says lenses like these will also be used to investigate how galaxies evolve over time.

Where the Roman Space Telescope comes in

Roman launched in August 2026 and is designed to survey huge areas of the sky with a wide field of view, far larger than Hubble’s. That makes it well suited to studying large numbers of lenses and building a statistical picture rather than one object at a time.

Having Hubble’s high-resolution images of these specific targets in hand means Roman’s science teams will already know what they are looking at, which can make follow-up work faster and more precise.

A team effort among NASA’s observatories

NASA frames the project as an example of how its big observatories work together. As Roman joins Hubble, the Chandra X-ray Observatory and the James Webb Space Telescope, the agency says, “a new window opens onto the universe, revealing sights previously hidden while expanding our cosmic knowledge for all of humanity.”

Each telescope has strengths: Hubble’s sharp optical images, Webb’s infrared sensitivity, Chandra’s X-ray vision and Roman’s wide survey view. Combining them gives astronomers a more complete picture than any one could provide.

Why it’s worth a look

Beyond the science, the images are simply striking. Galaxies bent into glowing arcs are a vivid reminder that space itself is shaped by mass, and that the universe is stranger and more beautiful than it looks with the naked eye.

The takeaway

Hubble’s new gallery of gravitational lenses is both a showcase and a starting line. It gives the Roman Space Telescope a ready-made list of targets for one of its key jobs: weighing galaxies and mapping the dark matter that holds the universe together. The older telescope is passing the baton, and the next leg of the race has just begun.

Image: Hubble Discovers 67 New Gravitationally Lensed Galaxies in the Distant Universe (2008-09-2262) by NASA, ESA, C. Faure (Zentrum Für Astronomie, University of H via Wikimedia Commons, Public Domain Mark 1.0