The Deep-Sky Menagerie
Beyond the Solar System lies a menagerie of clusters, nebulae, and galaxies. A path through the classes of deep-sky object — from the young open clusters and glowing HII regions to the cast-off shells of dying stars and the wreckage of supernovae — each tied to real objects you can find in the sky.
In pictures
Related entities
- Astrophysical object
Globular Cluster
A dense, roughly spherical swarm of tens of thousands to millions of very old stars, tightly bound by gravity and orbiting in the halo of a galaxy. Globular clusters are among the oldest structures in the Universe, and their tightly packed, coeval stars make them benchmarks for stellar ages and the early history of the Galaxy.
- Astrophysical object
Planetary Nebula
The glowing shell of gas cast off by a dying Sun-like star as it becomes a white dwarf, ionised and lit up by the hot stellar core at its centre. Despite the name — coined because their round disks resembled planets in early telescopes — planetary nebulae have nothing to do with planets; they are a brief, beautiful final phase of low- and intermediate-mass stars.
- Nebula
The Horsehead Nebula
One of the most recognisable dark nebulae in the sky — a column of cold, dusty gas in the Orion molecular cloud, about 1,500 light-years away, shaped by radiation into the silhouette of a horse's head. Catalogued as Barnard 33, it is seen against the soft red glow of the emission nebula IC 434 behind it, in the constellation Orion just south of the belt star Alnitak.
- Nebula
Orion Nebula
A diffuse emission nebula and active star-forming region, one of the brightest nebulae visible to the naked eye.