One of the most common types of island universes viewed during our journey
Space news (The Hubble Tuning Fork: barred spiral galaxies) – 55 million light-years from Earth toward the constellation of Coma Berenices (Berenice’s Hair) –
First documentedin the western world by German-British astronomer William Herschel, barred spiral galaxy NGC 4394 is a member of the most common type of galaxy viewed inthe Galaxy Zoo. Estimated by astronomers to be 55 million light-years from Sol, toward the constellation of Coma Berenices, this island universeis considered a member of the Virgo Cluster.
The prototypical barred spiral galaxy, NGC 4394 has bright spiral arms sprouting from the ends of a bar cutting through its middle bulge. Sprinkled with blue, young stars its spiral arms contain fuzzy regions where stars are being formed and dark filaments of cosmic dust. Near the center of this island universe lies a region of ionized gas known as a low-ionization nuclear emission-line region (LINER). An active region displaying a specific set of emission lines in its spectra, a LINER contains mainly weakly ionized atoms of oxygen, nitrogen, and sulfur.
LINERS have been viewed relatively often during the human journey to the beginning of space and time and they’re starting to piece together their puzzle. Astronomers still need to figure out where the energy comes from to ionize the gas. Presently astronomers believe it could be due to the influence of the supermassive black hole or extreme levels of star formation. In the case of NGC 4394, gas from a nearby galaxy has likely flowed into its central region, providing a new source to fuel the process, either way.
You can learn more about galaxies with a LINER here.
One small cog of a vast wheel of the Virgo supercluster
The distance involved in traveling to the next galaxy is staggering to consider
The Messier Catalogue
Astronomy News – Astronomers looking upward into the night sky realised centuries ago that deep-sky objects are distributed unevenly about the night sky. French comet hunter Charles Messier (1730-1817) looking upward into the night sky through his time-machine-to-the-stars compiled a popular catalog of deep-sky objects. His catalogue contains high concentrations of deep-sky objects within the Milky Way above you, where open star clusters and star-forming areas that form them congregate.
Messier’s catalogue also contains entries on 16 objects he located near the border between the constellations Virgo and Coma Berenices. Star gazer William Herschel (1738-1822) and his son, John Herschel (1792-1871), recorded more than 200 celestial objects in this same region of the night sky. It would be in the 1920s and 1930s that astronomers would determine that these nebulous objects are in fact galaxies as big, or larger than, the Milky Way galaxy that constitute a cluster of galaxies far beyond the Milky Way.
Our Local Group of galaxies
Two decades later, French-born astronomer Gerard de Vaucouleurs (1918-1995) noted that the halo of galaxies surrounding what astronomers referred too as the Virgo cluster actually extends all the way to our Local Group of galaxies, which the Milky Way calls home. Today astronomers refer to this Local Group of galaxies as our Local Supercluster of galaxies.
Presently, astronomers believe our Local Supercluster extends 50 million light-years, from the center of the Virgo cluster. We’ll journey from the center of our Local Group to slightly beyond the Virgo cluster. Along the way we’ll stop at all of the galaxy groups and clusters containing at least three reasonably large galaxies and see what astronomers have determined about these distant celestial bodies in the night sky above you.
The first celestial object in the night sky we’ll journey to see is called the Ursa Major North Group, next we’ll travel to Ursa Major South Group, and then make our way to each of the galaxy groups and clusters in the Milky Way’s Local Group of neighbors.
The first leg of the human journey to the beginning of space and time