Five stars form the Southern Cross constellation on the flag of Brazil. They appear inside the flag’s blue celestial disk, which represents the sky over Rio de Janeiro at the time Brazil became a republic.
The Southern Cross, known in Latin as Crux, is one of the best-known constellations in the Southern Hemisphere. On Brazil’s flag, its five principal stars are arranged as a cross, although the arrangement is shown as if viewed from outside a celestial globe, producing a mirrored appearance compared with ordinary sky maps.
Brazil’s flag was adopted on 19 November 1889, four days after the proclamation of the republic. The original republican flag had 21 stars; the current version has 27, representing Brazil’s 26 states and the Federal District. The stars are not merely decorative: each corresponds to a Brazilian federal unit.
A frequent mistake is to count all the stars in the blue disk when answering this question. The disk contains 27 stars in total, but only five of them form the Southern Cross. Other notable stars include Spica, representing Pará, and Sigma Octantis, representing the Federal District.