Triangulum Galaxy Facts

The name of the Triangulum Galaxy is due to the fact that it is located in a triangle-shaped constellation.

Triangulum Galaxy Profile

Also known as:Messier 33, M33 or NGC 598
Type:Spiral Galaxy
Diameter:60,000 light years
Distance:3 Million light years
Mass:50 billion M☉
Number of Stars:40 billion

It is part of the same Local Group as our own Milky Way Galaxy and is the third largest in our group.

The Triangulum Galaxy, like the Andromeda and Milky Way Galaxies is a spiral galaxy. When you see pictures of this galaxy it looks like its “arms” are loosely wrapped around its core.

The Triangulum Galaxy was discovered in 1764 by astronomer Charles Messier.

However, there was a continued dispute due to an Italian astronomer that first noted the galaxy in 1654. The scientific designation for the Triangulum Galaxy is M33.

Some of the spiral galaxies, including the Milky Way, have a very distinctive core with a bar shape.

What’s different about the Triangulum Galaxy

Triangulum Galaxy doesn’t have this bar and is called an un-barred spiral galaxy. A distinctive feature of the Triangulum Galaxy is that it has areas that are forming bright stars.

One of these bright star clusters is called NGC 604 and is considered to be a stellar “nursery.”

NGC 604 is the largest of these nurseries when compared to the Andromeda and Milky Way Galaxies, as well as a popular area to photograph because it is only 3 million light-years away.

Better photos

In 2007-2008 NASA’s Swift satellite took a lot of pictures focused on the Triangulum Galaxy.

At that time the satellite created the “most detailed ultraviolet image of an entire galaxy every taken.”

They included incredibly bright blues and purple colors that highlighted the formation of the stars within the Triangulum Galaxy.

Another famous photo was taken by Chris Schur, an Arizona photographer, when he took a stunning picture of the Triangulum Galaxy in 2016.

The Triangulum Galaxy is sometimes called the Pinwheel Galaxy in error. The Pinwheel Galaxy is designated as Messier 101 and is an entirely different galaxy.

The Triangulum Galaxy Shape

The shape of the Triangulum Galaxy may be due to a past interaction with the larger Andromeda Galaxy that is nearby.

Researchers believe there has been interaction because there are quite a few streams of stars and neutral hydrogen that are linking both galaxies.

Some scientists refer to the Triangulum Galaxy as an “inside-out” galaxy formation.

This is due to the theory that the gas at the galaxy’s inner core became exhausted and instead began to gather at the galaxy’s outer edges.

The result of this occurrence is a difference in compositions of the outer halo and inner core.

Facts about the Triangulum Galaxy

  • The Space Telescope Science Institute describes the colorful nebula of the Triangulum Galaxy/NGC 604 as “monstrous.”
  • Observations throughout the years have resulted in finding out that the Triangulum Galaxy is speeding towards the Milky Way Galaxy at a speed of 62,000 mph/100,000 km/hr.
  • NASA made a comment regarding NGC 604, stating that if it had a location that was the same distance from Earth as the Orion Nebula, outside of our Moon, it would be the brightest object in the night sky.
  • Estimating the size of the gas cloud in the Triangulum Galaxy, scientists indicated that it was 100 times larger than the Orion Nebula.
  • The gas cloud for NGC 604 is estimated to contain over 200 blue (hypergiant) stars and is around 1,300 light-years across.
  • Although scientists have indicated that the Triangulum Galaxy doesn’t have a central bar, other researchers have stated that it may actually have a bar but that it is too weak to be realistically considered.
  • Regions or areas in a galaxy where the stars are “born” or formed are called Hll regions. The larger the star, the shorter the life-span.
  • Astronomers have listed a belief that the Andromeda and Triangulum Galaxies are gravitationally trapped due to past interaction and their idea that there will be more interaction 2.5 billion years in the future.
  • The Triangulum Galaxy has a satellite galaxy known as Pisces Dwarf Galaxy.
  • An area near the Triangulum Galaxy appears like three bubbles that are inside of each other. Scientists think that this odd shape is the result of three different supernovae.
  • The black hole in the Triangulum Galaxy is considered to be the largest stellar mass of any discovered so far.


  • What is the distinctive feature that caused the name of the Triangulum Galaxy?
    it is located in a triangle-shaped constellation
  • How many blue (hypergiant) stars are thought to be in the gas cloud of the Triangulum Galaxy?
  • What is the scientific name designated for the Triangulum Galaxy?
    NGC 604
  • What type of classification is the Triangulum Galaxy?
    an un-barred spiral galaxy
  • When you look at pictures of the Triangulum Galaxy what do its “arms” appear like?
    loosely wrapped around its core
  • What description did the The Space Telescope Science Institute give for the nebula of the Triangulum Galaxy?