
The Pleiades, or Seven Sisters, is the most famous open star cluster in the sky — a glittering swarm of more than 1,000 hot young blue stars, a handful of which are easily visible to the naked eye and have been celebrated by cultures worldwide since ancient times. Wisps of blue reflection nebulosity drape its brightest members, the dusty remnant of a passing interstellar cloud lit up by the cluster's brilliant stars roughly 444 light-years away in the constellation Taurus.