These images, taken between 1994 and 2016 by NASA's Hubble Space Telescope, chronicle the brightening of a ring of gas around an exploded star.
The stellar blast, called Supernova 1987A, was first spotted 30 years ago. The explosion is the nearest supernova event in more than 400 years. Hubble began watching the blast's aftermath shortly after the space telescope's launch in 1990.
The growing number of bright spots on the ring was produced by a shock wave unleashed by the blast, which is slamming into the ring of gas, heating it up, and causing it to glow brighter. The ring, about one light-year across, was probably shed by the star about 20,000 years before the explosion.
Astronomers detected the first bright spot in 1997, but now the whole inner ring has brightened and looks like a string of pearls. Only Hubble can see the individual knots.
The bright spot that appears on the ring at lower right is actually a foreground star. Supernova 1987A is 163,000 light-years away in the Large Magellanic Cloud.
The images were taken with Hubble's Wide Field Camera 3, Wide Field Planetary Camera 2, and Advanced Camera for Surveys.