Astronomy
The Lyra Constellation and Its Variable Star Systems
Quick fact
RR Lyrae stars, named after the prototype in Lyra, pulse with periods of 0.2 to 1 day and are so consistent that their brightness reveals exactly how far away they are, helping astronomers measure distances to nearby galaxies.
Why this is interesting
Look up on a summer night and you'll see Vega, one of the brightest stars in the sky. But hidden in the same constellation are stars that blink with a heartbeat—some so regular they've become cosmic rulers.