3) These spiral nebulae were also observed spectroscopically, which means the light coming from them was broken up into individual wavelengths, recorded and analyzed.

A hundred years ago, astronomer Edwin Hubble revealed a universe of galaxies that existed beyond ours. His influence in astronomy continues to this day.

A “nebula,” the Latin word for cloud, ... Originally, astronomers thought they were one and the same and thought of objects like the Andromeda Galaxy as a spiral nebula within our galaxy.

This remarkable image seems to show a perfect spiral in space. It’s created by a neighboring star which is leaking dust and particles, forming a new nebula. This image from the Hubble Space ...

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.

This planetary nebula with spiral arms is also known as Menzel 2, after the US astronomer Donald Menzel who discovered it in the 1920s. It is located in Norma, ...

He argued that the analysis of light from spiral nebulae indicated that they were clusters of stars (with similar features to the spectrum of light from the Milky Way itself).

1924: Astronomer Edwin Hubble announces that the spiral nebula Andromeda is actually a galaxy and that the Milky Way is just one of many galaxies in the universe. Before Copernicus and Galileo ...