Day 5 of the 2025 Space Telescope Advent Calendar: Colorful Stars of All Ages
Spiral galaxy NGC 6000, about 100 million light-years away and 66,600 light-years across, shows older yellow central stars and younger blue outer-arm stars.
We Had a Name for Galaxies' before We Knew They Existed
Astronomical jargon often uses counterintuitive terms like "metal" for all elements heavier than helium, and some obsolete classifications remain in use.