A third category – nebulae with spiral structure – particularly intrigued astronomers. The Andromeda nebula, M31, was a prominent example. It’s visible to the naked eye from a dark site.

Galaxies shine in a rainbow of emissions from gas, dust, and stars. Each of these building blocks emits light at specific ...

Hubble worked hard, taking images of spiral nebulae every clear night and looking for the telltale variations of Cepheid variables. By the end of 1924, he had found 12 Cepheids in M31.

The powerful device will scan the sky like never before, capturing vast amounts of data to reveal how the universe changes ...

About 100 years after astronomer Edwin Hubble's discovered the "magnificent" spiral nebula, the Hubble Space Telescope and NASA scientists have produced the most comprehensive survey of the ...

M51’s pronounced arms caused astronomer William Parsons, Earl of Rosse, to call it a “spiral nebula” in 1845. In the two centuries that followed, ...

The headline read: Finds Spiral Nebulae are Stellar Systems: "Dr. Hubbell Confirms View That They Are 'Island Universes'; Similar to Our Own." On Sunday November 23, 1924, ...

Putting Isaac Roberts’ astonishing 1888 photographs of the Great Nebula in Andromeda and other spiral nebulae to cosmic effect at his argument’s outset, Pettigrew then immersed the reader in a ...