Roman is about to hide the stars—and bring their planets into view

The SETI Institute published a new conversation on August 12 with senior scientist Margaret Turnbull about NASA’s Nancy Grace Roman Space Telescope and its Coronagraph Instrument. Most known exoplanets were found indirectly, through transits or their gravitational pull. Roman will instead try to block a star’s overwhelming light so the far fainter reflected light from nearby planets can emerge.

Roman’s first coronagraph observations will focus on giant planets and debris disks, using spectra to look for molecules such as methane and compare alien atmospheres with Jupiter’s. The instrument is a technology demonstration, but success would help clear a path for future observatories designed to directly image smaller, potentially habitable worlds around nearby Sun-like stars.

Why it matters

Directly separating a planet’s light from its star opens a richer investigation: researchers can study the world’s atmosphere and surroundings instead of only inferring that it exists.

What the source establishes

Roman’s coronagraph is designed to demonstrate next-generation direct-imaging technology. Its first targets will be giant planets; it is not expected to photograph an Earth twin or detect life by itself.