10 Triangulum Galaxy Facts

If you’re looking for some information about the Triangulum galaxy, then you’re in the right place. It makes up part of the Local Group of galaxies, which includes our own Milky Way, meaning that it’s one of the most distant objects that can still be seen with the naked eye if you look hard enough. 


This is a galaxy that’s easy to find in the night sky and typically visible if you’re in the Northern hemisphere due to its declination. Let’s look at some facts about the Triangulum galaxy.

Triangulum Galaxy Facts

  1. The radius of the Triangulum galaxy is around 30,000 light years. This makes it’s smaller than our Milky Way, and less than 30% of the size of the Andromeda galaxy.
  2. The Triangulum galaxy is named as such because it is located in the Triangulum constellation.
  3. If you’re trying to see the Triangulum galaxy, then it is located just to the right of the constellation. It is slightly to the East of Mothallah, which is the Alpha and brightest star of Triangulum. 
  4. It appears so bright to us because it is actually quite close – it is only 2.7 million light years away, which in galaxy terms, isn’t actually that much. Of course in human terms, it’s still very far away!
  5. You might see the Triangulum galaxy referred to as M33. This is because it is number three in the Messier catalog, which is a collection of astronomical objects.
  6. The Triangulum galaxy is a member of the Local Group, a group of 30 or more galaxies. The largest of this group is the Andromeda galaxy, and the second largest is us, the Milky Way.
  7. It is defined as a spiral type of galaxy, due to its lack of a bar of star running through its center. This is the same as the Pinwheel galaxy.
  8. Although we aren’t 100% sure of this, we think that the Triangulum galaxy is likely a satellite of the Andromeda galaxy due to it’s proximity. 
  9. It’s estimated that there are around 10% of the 400 billion stars that we have in the Milky Way, giving the Triangulum constellation around 40 billion stars overall.
  10. Triangulum is well known for its area NCG 1604, which has one of the fastest rates of starbirth in the Local Group.

Common Questions about the Triangulum Galaxy

Who discovered the Triangulum galaxy?

Whilst we aren’t 100% sure who discovered the Triangulum galaxy, astronomers usually give Giovanni Battista Hodierna the credit for this. The Italian astronomer had written about the bright nebula located to the East of Triangulum, so this is why we give him credit. However, the object was later discovered separately by Charles Messier and added to his catalog of astronomical objects – this was 100 years after Hodierna had first written about it, though.


Will the Triangulum galaxy collide?

Different astronomers will give you a different opinion to this. Many astronomers believe that when the Milky Way and the Andromeda galaxy collide with each other, they will then pull the Triangulum galaxy into the collision too. However, some astronomers believe that the Triangulum galaxy will then begin to orbit the merged galaxies instead.

How fast is the Triangulum galaxy at forming stars?

Whilst we don’t have an exact rate of how fast the Triangulum galaxy forms stars, astronomers say that on average it can form stars faster than that of the Andromeda galaxy.


Can I see the Triangulum galaxy?

You probably won’t be able to see the Triangulum galaxy if you aren’t using a telescope. However, if you have an amateur telescope at one, even one with a relatively low aperture, then you should be able to see the Triangulum galaxy. It is located just to the East of the main constellation.

What type of galaxy is the Triangulum galaxy?

The Triangulum galaxy is defined as a spiral galaxy – it is the smallest spiral galaxy in our group of galaxies, the Local Group.


All in all, the Triangulum galaxy is one of much interest to us in the Milky Way, primarily due to it’s close proximity to us. As part of the Triangulum constellation, it is quite easy to locate in the night sky if you’re trying to find it, too. Hopefully you’ve learned something about this galaxy! 


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