NASA’s Roman Space Telescope could find alien Earths—but not like you think

image via New Scientist

August 29, 2026, 1:00 PM

• •NASA’s Nancy Grace Roman Space Telescope is set to spend more than a quarter of its five-year primary mission surveying the Milky Way’s central bulge.
• •Its Galactic Bulge Time-Domain Survey will watch hundreds of millions of stars, taking an image about every 12 minutes to catch rare microlensing events and repeated transits.
• •Microlensing could reveal small rocky planets, including Earth-size worlds, as well as free-floating planets, but most such detections will be difficult to study again because the alignments are one-time events.
• •Roman’s transit observations could add roughly 100,000 exoplanets, with sensitivity potentially extending down to objects as small as the moon.
• •Scientists also expect the survey to uncover brown dwarfs, neutron stars, stellar-mass black holes and clues about the ages and formation history of stars in the galactic bulge.

NASA’s Nancy Grace Roman Space Telescope will devote more than a quarter of its primary mission to observing the Milky Way’s densely packed central bulge. By repeatedly imaging hundreds of millions of stars, the telescope will search for exoplanets through both gravitational microlensing and planetary transits. Scientists expect the survey to reveal whether small rocky planets, including Earth-size worlds and even free-floating planets, are common in this region of the galaxy. The observations may also uncover brown dwarfs, compact stellar remnants and new clues about the age and history of stars in the galactic bulge.

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