Red giants in the center of the Milky Way resemble distant lighthouses that brighten and dim. Their light pierces through dense dust, but standard distance-measuring methods fail here: the stars are too bright and unstable, and dust distorts the picture.

Astronomers found a workaround. They took stars whose distances were already known from other data and taught a computer model to link that distance to the star's color in infrared light. The model, like a smart calculator, now estimates distance from several 'shades' of infrared glow. The error turned out to be small — about 6% on test data.

With the new tool, astronomers measured distances to more than 36,000 red giants — from 0.5 to 20 thousand light-years. It's as if we suddenly had a detailed ocean depth map where only scattered soundings existed before.

Of particular interest were Mira-type variable stars. Those that pulsate more slowly clustered in the center of the Galaxy, tracing the shape of the elongated bar — our Galaxy's bar. The faster pulsators scattered across the disk. The difference in the 'growth' of these stellar populations hints at how the Milky Way formed.