10 Weird and Wonderful Galaxies
tl;dr: check out our 10 Galaxies and Weird Facts Infographic.
No one would deny that Galaxies are one of the most stunning objects in all of the Universe. But did you know, they can be weird and also wonderful, even at the same time?
The classical definition of a galaxy states that “…a galaxy is a collection of stars and planets that are held together by gravity,” additionally, “…in a galaxy, the celestial bodies rotate around a central object.” This definition is fine as far as a scientific explanation goes; but it doesn’t convey the grandeur and majesty of a galaxy when seen from up close.
To some astronomical observers, galaxies can become a little hum-drum and somewhat boring after a while. No matter how many times you’ve seen a awe-inspiring galaxy in an enhanced image; it’s important to sometimes take a step back and to look at these magnificent star-cities in a new light or through new eyes, so to speak.
This list is a new look at familiar objects and we hope you enjoy this tour of some weird and wonderful galaxies with us. Enough already, so here it is, our list of the top 10 Weird and Wonderful Galaxies.
#10 – Hoag’s Object
Hoag’s Object Quick Facts:
- Distance from Earth: 612 million light years.
- Located in the Serpens Caput Constellation.
- Diameter: 121,000 light years.
At first glance, this weird galaxy looks like something straight off the cover of a science fiction novel. However, Hoag’s Object is one of about a dozen similar galaxies discovered so far, but when the scientific community was asked just how such a galaxy could have formed, the answer was a collective “Say what?”
The really weird thing is that another Ring Galaxy, as this class of galaxy is known, can be seen between the bright core and the outer ring. The processes that form these galaxies are unclear, and as matter stand now, there are no proposed theories or hypotheses to explain their formation.
#9 – Arp 87
Arp 87 Quick Facts:
- Arp 87 (NGC 3808), consists of two interacting galaxies NGC 3808A, and NGC 3808B.
- Distance from Earth: 300 million light years.
- Located in the Leo Constellation.
- Diameter: 75,000 light years.
Collectively known as Arp 87, after Halton Arp, who discovered it, this pair of galaxies is the perfect example of how the gravitational fields of two galaxies interact with each other over extended distances.
The distortions in both galaxies are the result of a near collision some billions of years ago, but it seems unlikely that either galaxy will escape the tidal forces of the others’ gravity. It is much more likely that the pair will keep on circling each other until they eventually merge into one gigantic elliptical galaxy a few billion years from now. Note the tenuous “leash” of gas, dust and stars that forms a bridge between the two antagonists.
#8 – Antennae Galaxies
Antenna Galaxies Quick Facts:
- Distance from Earth: 45 – 65 million light years.
- Located in the Corvus Constellation.
- Diameter: 350,000 light years.
In this example of a galactic collision, the more massive component of the Antennae Galaxies is in the process of “swallowing” the less massive galaxy.
The bright blue arcs of light are active star forming regions, in which stars at forming at a rate that places the structure in the “Star Burst” category. This means that stars are forming at such a furious pace that all of the bright pink and red gas clouds will be consumed to form new stars. Note the two bright yellow spots in the image, these blobs used to be the respective cores of the two galaxies involved in this deadly encounter. In a few billion years all that will remain is a huge, elliptical galaxy.
#7 – Sombrero Galaxy
Sombrero Galaxy Quick Facts:
- Distance from Earth: 28 million light years.
- Located in the Virgo Constellation.
- Diameter: 50,000 light years.
As its name suggests, the Sombrero Galaxy is a peculiar galaxy resembles a passing resemblance to a Mexican sombrero. However, what’s visible in this image is only the central bulge around the core of the galaxy. The main structure of the galaxy falls outside the limits of this image, but the really weird thing about the galaxy is the dark dust lane that encircles the core.
At present, there is no explanation for this feature, which come to think of it, should not be there at all, given the force of the radiation emanating from the core. Nonetheless, it has been suggested that the super-massive black hole in the center of the bulge may somehow feature in the origin and retention of the dust lane.
#6 – Centaurus A
Centaurus A Quick Facts:
- Distance from Earth: 11 million light years.
- Located in the Centaurus Constellation.
- Diameter: 25,000 light years.
To the uninitiated, Centaurus A, which is invisible without optical aid, may just be another active galactic nucleus that radiates copious amounts of radio waves.
However, a closer look will reveal the presence of the remains of a spiral galaxy under the bright pink star forming region. In this case, the weird thing is the fact that the spiral structure of the assimilated galaxy has remained relatively intact – usually galactic mergers destroy both galaxies.
Also invisible in this image are the two lobes of radio emissions that extend for more than a million light years in opposite directions from the center of the structure.
#5 – The Southern Pinwheel
Southern Pinwheel Quick Facts:
- Distance from Earth: 15 million light years.
- Located in the Hydra Constellation.
- Diameter: 55,000 light years.
This magnificent sight is not only one of the most luminous galaxies in the entire night sky; but it’s also the location of eight observed supernova explosions and the home of the remnants of several hundred more. The Southern Pinwheel Galaxy, also known as Messier 83, is one of the most famous and recognized galaxies of them all.
The abundance of supernovae and their remains is perhaps not so surprising if we consider the fact that the pink color that derives from the UV radiation of millions of new-born stars This pinkish glow permeates the galaxy, which is a sign of star formation at a very rapid pace. Thus, the more stars that are born, the more stars die – hence the high number of supernova explosions.
Many observers describe the Southern Pinwheel as the most beautiful of all galaxies, which might be a subjective opinion, but what do you think?
#4 – NGC 474
NGC 474 Quick Facts:
- Distance from Earth: 100 million light years.
- Located in the Pisces Constellation.
- Diameter: 250,000 light years.
While there are many weird and wonderful shapes in the Universe, the shells of gas and dust being blasted off the galaxy, known as NGC 474, in the foreground defies explanation.
The bright white and yellow dot in the image is the core of the galaxy which is in the process of colliding with the massive spiral galaxy behind it. On the face of it, both galaxies should be affected by the encounter given their close proximity, but for some unexplained reason, the foreground galaxy is getting the worst of it.
One theory states the wispy shells are the remains of dwarf galaxies destroyed by the foreground galaxy. Another theory suggests the shells are the disturbed (and now illuminated), irregular halos most known-galaxies are thought to possess. Only time will tell.
#3 – NGC 660
NGC 660 Quick Facts:
- Distance from Earth: 45 million light years.
- Located in the Pisces Constellation.
- Diameter: 50,000 light years.
The wonderful thing about the NGC 660 Galaxy is the fact that out of the millions of galaxies that have had their pictures taken, only about a dozen or so polar ring galaxies have been spotted.
The almost perfectly circular ring that spans the galaxy across its poles is believed by most investigators to be the result of an interaction with a less massive galaxy a few hundred million years ago.
It is believed that the material comprising the less massive galaxy was “siphoned” off very slowly to enable it to re-arrange itself in the ring structure. A more direct, head-on type encounter would likely have destroyed both galaxies, but the behavior of the ring’s structure is being studied in efforts to learn more about the forces that keep galaxies together.
#2 – The Porpoise Galaxy
Porpoise Galaxy Quick Facts:
- Distance from Earth: 230 – 326 million light years.
- Located in the Hydra Constellation.
- Diameter: 110,000 light years.
This picture of a dolphin-shaped galaxy, also known as Arp 142, is another very good example of how a massive galaxy can ravish a less massive structure without itself being affected by the encounter. The bright galaxy below the “dolphin” is known as Arp 142 and its tidal forces are flattening, bending and stretching out the remains of the spiral galaxy NGC 2936, above it.
The bright yellow “eye” of the dolphin is in fact the core of the spiral galaxy and the bright blue region that forms the “nose” to the left of it is an area in which millions of new stars are forming as a direct result of the encounter. Note the bright white and red spiral galaxies near the “tail” of the dolphin.
#1 – The Black Eye Galaxy
Black Eye Galaxy Quick Facts:
- Distance from Earth: 19 million light years.
- Located in the Coma Berenices Constellation.
- Diameter: 70,000 light years.
Apart from the fact that the Black Eye Galaxy, also known as Sleeping Beauty Galaxy or Messier 64, looks far more like an artist’s impression than an actual galaxy, the weird thing about it is that it consists of two galaxies that are rotating in opposite directions.
The central, reddish part is rotating in one direction, while the outer, blue part is an assimilated galaxy that rotates in the opposite direction. It’s not quite clear how this came about, but the prevailing theory is that it is due to the particular circumstances that occurred during a merger between two galaxies of about equal mass. Which does not explain much, except to say that the red color of the central part indicates a high rate of star formation.
Useful Facts to Know About Galaxies:
- A light year is a unit of distance and not of time. It refers to the distance light travels in one year – a total of 5.87849981 x 1012 miles, about 9.4605284 x 1012 km. Expressed as a simple number, the distance is enormous: 5,878,499,810,000 miles or 9,460,528,400,000 km.
- Travelling at 186,000 m/per sec (299,792 km/per sec) through the vacuum of space, it takes light from the Sun just over 8 minutes to reach Earth. By way of comparison, if we say that the diameter of the Milky Way Galaxy is 100,000 light years, it will take light 100,000 years to cross the disk of the galaxy from one side to the other.
- Galaxies are not defined by clear-cut boundaries. From their centers of mass, star density declines in direct proportion to the distance from the center; however, the extent of what constitutes a galaxy can be expressed as the limit within which stars occur at a density of 1 star per 100 light years squared. Within this limit, stars will be held together by their collective gravitational fields.
- Most galaxies emit copious quantities of light in wavelengths that are invisible to human vision. There are many examples of this, but a case in point is the X-ray radiation emitted by IC 1101, which extends to a distance of 6 million light years beyond its visible “boundary” (see image below).
We hope that you liked the 10 Weird and Wonderful Galaxies we choose to feature. If you think we missed some or should do another list and include more, let us know which galaxies you think should have been included in the comments below.