In 1920, astronomers Harlow Shapley and Heber Curtis held a Great Debate. Shapley argued that the spiral nebulae were small and in the Milky Way, while Curtis took a more radical position that they ...

At the dawn of the 20th century, the nature of the night sky’s “spiral nebulae” puzzled astronomers. Unlike other celestial objects cataloged by Charles Messier in the late 1700s ...

The second key was the work of Vesto Slipher, who had investigated the spiral nebulae, before Hubble's Andromeda discovery. These bodies emit light which can be split into its component colors on ...

As it nears 35 consecutive years of space service, the NASA/ESA Hubble Space Telescope has taken another look at a famous ...

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.

In fact, all the many galaxies scattered through the sky were referred to as spiral nebulae. Even though a lot of them, of varying sizes, shapes, and orientations, were visible in the night sky ...

Astronomy is arguably the oldest science, and has featured strongly throughout the history of Nature — the first quasar, the first exoplanet, the nature of spiral nebulae, to name but a few of ...

The second key was the work of Vesto Slipher, who had investigated the spiral nebulae, before Hubble's Andromeda discovery. These bodies emit light which can be split into its component colors on ...

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.

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.