Is This the Loneliest Galaxy in the Universe?
Shimmering deep inside a cosmic supervoid is MCG+01-02-015, a pristine galaxy that is the undisputed galactic loner of the universe.
The universe has structure: long filaments of dark matter threaded with galaxies and clusters of galaxies punctuated by vast voids. These voids are just that; devoid of the rich concoction of stars that are beaded along the universal 3-dimensional web of matter. But, as this Hubble Space Telescope observation shows, not all voids are completely empty.
This spiral beauty, as seen by Hubble's Advanced Camera for Surveys, has the unromantic designation of "MCG+01-02-015," but it's situation inspired the European Space Agency to describe it as "the loneliest of galaxies" - a galaxy that is stuck inside a void in the direction of the constellation Pisces.* How the galaxy got there, it is not known. Perhaps it was it born there? Did an island of gas find itself in the middle of a sparsely populated volume of the cosmos, only to spark its galactic evolution in solitary confinement? Or did some gravitational turmoil, billions of years in the galaxy's past, hurl MCG+01-02-015 into the void?
As lonely as it is, MCG+01-02-015 isn't alone; we know of other "void galaxies" -- inside the famous 250 million light-year-wide Boötes void for example. Some theories suggest these void galaxies may be some of the most pristine examples of galactic evolution, having been formed in near-isolation away from the turmoil of other galactic encounters, forming from the soup of primordial intergalactic gases. And looking at MCG+01-02-015, it does look like a picture-perfect spiral galaxy.
Included in this observation are 3 foreground stars, all from our own galaxy - those 3 points of bright light with obvious diffraction spikes. But these are the only individual stars in Hubble's field of view, all other points of light are background galaxies, each containing billions of stars, some also with elegant spiral structures. Even that spiral galaxy just below of MCG+01-02-015 is far behind and likely out of the void.
Interestingly, according to ESA, "the galaxy is so isolated that if our galaxy, the Milky Way, were to be situated in the same way, we would not have known of the existence of other galaxies until the 1960s." It's hard to imagine how isolated MCG+01-02-015 is, our Milky Way galaxy is living in a thriving galactic metropolis in comparison! For any hypothetical aliens living in the void, lacking advanced telescopes and astronomical imaging techniques, the universe would look like a far different place than what we are accustomed to.
With the help of powerful space telescopes like Hubble, humankind hasn't only become accustomed to the countless billions of galaxies, we've built a 3-D picture of the "cosmic web" of galaxies, all held together by a gravitational force that can only be there if the majority of the cosmos is composed of an invisible mass called dark matter. But where there are giant filaments of matter, there's monstrous voids separating them and, occasionally, we find inextricable galaxies that have somehow become trapped inside, the undisputed galactic loners of the universe.
*CORRECTION (11/22/15): A previous version of this article misstated that MCG+01-02-015 is a void galaxy of the Boötes Void. It is not, it is a galaxy inside a void in the direction of the constellation Pisces. The text has been corrected to reflect this change. Many thanks to astronomer Richard Drumm for spotting this error.
Using data from the Hubble Space Telescope's famous Ultra-Deep Field (UDF) observation,
. Since its launch in 1990, the veteran observatory has studied countless galaxies, but some of the most striking images are that of the majestic spirals that pervade the entire observable universe. In this celebration of spiral galaxies and Hubble's prowess at imaging them, we've collected some of our favorite galactic views from the space telescope's archives.
In this majestic image, phenomenal detail in galaxy
's spiraling dust lanes have been captured.
as seen nearly edge-on from Hubble's perspective. The dark galactic dust silhouettes the bright galactic core.
located deep within the Coma Cluster of galaxies, around 320 million light-years away in the northern constellation Coma Berenices, shows off some intricate detail in its arms.
(Messier 104) is an edge-on spiral galaxy -- the "rim" of the sombrero is thick lanes of dust obscuring the galaxy's starlight.
is another spiral galaxy not too dissimilar to our Milky Way. Young, bluish stars track along the galaxy's majestic arms, while older, redder stars cluster in its bright core.
This unique view of
is a combination of Hubble data and photographs taken by astrophotographer Robert Gendler.
The 'classic' spiral
gravitationally interacts with a neighboring galaxy, refining its very clear spiral arms.
To celebrate Hubble's 21st year in space, astronomers released this striking image of a pair of interacting galaxies called
. (Image rotated)
The 3 galaxies of
appear to be very close to one another, but astronomers believe that they are far apart and only overlapping from our perspective.
is undergoing some violent gravitational disturbances after a suspected galactic collision. The creation of the stream of stars post-collision appear as a tail, giving the galaxy "The Tadpole" moniker.