Surface Brightness Fluctuations

Surface Brightness Fluctuations (SBF) is a technique used in astronomy to measure the distance to galaxies. It relies on the fact that the glow of a galaxy’s light isn't perfectly uniform—small variations arise because of the random distribution of its stars. Nearby galaxies show more noticeable fluctuations, while distant ones appear smoother. By analyzing these brightness variations, astronomers can determine how far away the galaxy is. Essentially, SBF acts like a cosmic measuring stick, helping us understand the scale of the universe with precision.