One of the most stunning galaxies hanging around in deep space is the Cartwheel Galaxy.

It is incredibly beautiful with a stunningly bright core and equally beautiful ring that makes it look like a cartwheel. Of course, that’s not everything about the galaxy.

Let us learn a few interesting Cartwheel Galaxy facts and find out about its structure, its features and of course, its location, alternative names etc. Ready? Let’s begin…

Galaxy NameCartwheel Galaxy, MCG-06-02-022a, AM0035-335, ESO 350-40, PGC 2248
Galaxy TypeRing Galaxy and Lenticular Galaxy*
Striking FeatureResembles a wagon wheel and hence its name
DiscoveryDiscovered in 1941 by Fritz Zwicky
Distance from Earth496 million light years or 150 megaparsec
Apparent Magnitude15.2
Diameter150,000 light years
Mass of GalaxyBetween 2.9 and 4.8 billion M☉ where M☉ means solar mass that is, mass of our Sun

* A Lenticular Galaxy is something between a Spiral Galaxy and an Elliptical Galaxy. It appears like a fading Spiral Galaxy but its composition and other features appear similar to that of an Elliptical Galaxy.

Cartwheel Galaxy Facts: 1-10

1. Cartwheel Galaxy is a deep space or deep sky galaxy that is a southern constellation known as the Sculptor.

2. Sitting at an approximate distance of 496 million light years, the galaxy has a diameter of nearly 150,000 light years, making it slightly larger than our own Milky Way Galaxy.

3. It was Fritz Zwicky – a Swiss astronomer – who discovered the galaxy in year 1941

4. The galaxy is moving away from us at a very high speed of 9,050 kilometers per second.

5. With a mass of anywhere between 2.9 billion M☉ and 4.8 billion M☉, the galaxy is spinning at a high speed of 217 kilometers per second.

6. The galaxy has a distinct bluish ring encircling the bright inner core.

7. Between the bright inner core and the outer bluish ring are many stars that can be seen only in the ultraviolet spectrum.

8. Various images of the Cartwheel Galaxy captured by astronomers have revealed that more distant and faint galaxies are present around the Cartwheel Galaxy, near Sculptor Wall.

9. They all (together with the Cartwheel Galaxy) form a behemoth galaxy cluster structure that extends billions of light years outwards.

10. Cartwheel Galaxy is one of the local universe’s brightest sources for emitting ultraviolet light.

Cartwheel Galaxy Facts: 11-20

11. Initially, the galaxy was nothing more than a simple Spiral Galaxy just like our Milky Way Galaxy. However, some 200 million years ago, an accident occurred.

12. There was a smaller companion galaxy to the present-day Cartwheel Galaxy. This smaller companion galaxy came in and rammed nearly head-on with the present-day Cartwheel Galaxy and passed right through the disk.

13. What happened next was that a massive shock wave was generated that traveled through the Cartwheel Galaxy. To understand it, throw a rock in a pond and see how the ripples move out.

Now just imagine the rock as the smaller galaxy that passed through. The ripples are the shock waves, and the pond is the ancient Spiral Galaxy, which is now the Cartwheel Galaxy.

14. Traveling at a speed of 200,000 miles an hour, the shock wave or the cosmic tsunami swept gas and dust, triggering star-forming activity in the central region of the galaxy. The core of the original Spiral Galaxy was left unscathed.

15. This cosmic collision was so intense that the central core of the original galaxy became very unstable. Spinning around the core was a large electromagnetic field that spun at a very high speed.

16. Because of the electromagnetic field, the core of the original galaxy then started producing massive stars, and at the same time, expelled the stars in a ring pattern.

17. The shot out stars had a high velocity, which combined with the immense gravity of the core of the stars, kept the stars stable in the bluish ring that we see in the Cartwheel Galaxy.

18. However, with passage of time, the central core of the Cartwheel Galaxy became stable, but still continues to produce and eject stars in the same ring pattern. Only now, the ejection speed wasn’t high enough to send the stars all the way up to the bright ring.

19. Instead of reaching the bright ring, the stars now hung around in between, producing the spokes extending all the way from the core of the Cartwheel Galaxy to the outer bluish ring.

20. These spokes are also called arms of the galaxy and the original spiral shape of the galaxy is gradually re-emerging.

Cartwheel Galaxy Facts: 21-30

21. The stability that the central core of the Cartwheel Galaxy achieved was not really permanent. The core attained instability once again.

22. The result of the newfound instability was that the central core once again started producing stars and started ejecting them.

23. Only this time, the ejected stars did not reach far enough, making a smaller inner ring. This inner ring is made up of what astronomers and scientists prefer calling – ‘balls-of-light’.

24. The balls-of-light are very large and are in a constant decay mode. In the process of decaying, these larger ones are leaving behind streams of smaller balls-of-light.

25. These streams of smaller balls-of-light together produce comet-shaped large structures.

26. Though not a very highly popular model, this alternative model named ‘Ball-of-Light Particle Model’ says that the central core of the galaxy was made of a large ball-of-light.

27. This large ball-of-light eventually became very unstable and split apart to form two or three balls-of-light.

28. At least one of these split out balls-of-light eventually became one of the smaller galaxies that we see near the Cartwheel Galaxy.

29. According to this hypothesis, the split out ball-of-light moved away from the parent galaxy, but in the process, left off trail.

30. The trail connecting the smaller galaxy and the Cartwheel Galaxy is made of a hydrogen gas (neutral) trail and other material. Basically, this trail is more like a bridge between the Cartwheel Galaxy and the nearby small galaxy.

Cartwheel Galaxy Fun Facts: 31-40

31. The smaller galaxy which collided with the Cartwheel Galaxy (when it was originally a spiral galaxy) went past to the other side straight through the Cartwheel Galaxy.

32. Scientists say that one of the two smaller galaxies that we see nearby is the intruder galaxy that passed through after a nearly head-on collision.

33. Most likely, the smaller galaxy which passed through the Cartwheel Galaxy is the smaller bluer galaxy because it appears disrupted.

34. Not just disrupted, that galaxy also has young blue stars and has evidence of formation of new stars, making it a strong contender for being the intruder galaxy.

35. However, it doesn’t mean that the other one which is not bluish and is actually yellowish is not the intruder. It may be. The possible hypothesis is that when it passed through the Cartwheel galaxy, the intruder was stripped of its gas, and hence, there is no new star forming activity.

36. The Cartwheel Galaxy is a starburst galaxy. It is so called because new stars are being formed in great numbers.

37. Starburst galaxies usually have enormously large new stars that are extremely luminous. However, when these stars come to an end of their life, they explode in what we call a supernova explosion.

38. Cartwheel Galaxy is no different. The enormous stars end up in supernova explosions at the end of their lives and leave behind either a black hole or a neutron star.

39. Usually these black holes and neutron stars have companion stars. However, because the black holes and neutron stars have immense gravity, they rip off matter from the companion stars.

40. The immense gravity of the black holes and the neutron stars lead to the formation of accretion discs.

Cartwheel Galaxy Facts: 41-50

41. The accretion discs are formed by the matter that has been stripped from the companion stars.

42. When the stripped off material falls into the immensely powerful gravitational fields of the neutron stars or black holes, powerful X-Rays are emitted.

43. Interestingly, the Cartwheel Galaxy has a large number of such black holes in what are known as binary systems.

44. Astronomers have discovered at least one dozen X-Ray sources in the Cartwheel Galaxy. Usually, one or two are found in galaxies.

45. There is another type of X-Ray source in Cartwheel Galaxy. The X-Rays are also emitted by supernova remnants and young supernovas. Both sources produce X-Rays that are either hyperluminous or ultraluminous X-Rays (represented as U/HLXs).

46. Here is something interesting. The bright blue ring that we see in the Cartwheel Galaxy has always been (historically) thought to be the galaxy’s outermost boundary.

47. The diameter of the ring is 150,000 light years, making the galaxy slightly bigger than our Milky Way Galaxy.

48. This notion is changing. A recent study (by GALEX space telescope) has revealed that beyond the blue ring there is another ring, which has twice the diameter of the blue ring. This ring is really faint, and hence, difficult to see.

49. However, if that size of the newly discovered outer ring is taken into consideration, the Cartwheel Galaxy becomes 2.5 times the size of our Milky Way Galaxy. This means that our very own galaxy can nicely fit inside it.

50. The bright blue ring of the Cartwheel Galaxy that we see is home to several billion stars. There are far more in the entire galaxy.


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