The Planets

  • Planets
    • Mercury
    • Venus
    • Earth
    • Mars
    • Jupiter
      • Jupiter Red Spot
    • Saturn
    • Uranus
    • Neptune
  • Solar System
    • Dwarf Planets
      • Ceres
      • Pluto
      • Haumea
      • Makemake
      • Eris
      • Sedna
    • Moons
      • Moons of Saturn
      • Moons of Jupiter
    • The Sun
    • The Moon
      • New Moon
      • Waxing Gibbous Moon
      • First Quarter Moon
      • Waxing Crescent Moon
      • Full Moon
      • Lunar Eclipses
    • Asteroid Belt
    • The Heliopause
    • Kuiper Belt
    • Oort Cloud
    • Solar Eclipses
  • Objects
    • Asterisms
    • Asteroids
    • Comets
    • Constellations
    • Gas Giants
    • Meteorites
    • Meteor Showers
    • Stars
      • Star Clusters & Clouds
      • Types Of Stars
    • Terrestrial Planets
  • Galaxies
    • Black Holes
    • Andromeda
    • Antennae
    • Centaurus A
    • The Milky Way
    • Magellanic Clouds
    • Pinwheel
    • Sombrero
    • Triangulum
    • Whirlpool
    • Types Of Galaxies
    • Superclusters
  • Tools
    • Buying Guides For 2023
    • Your Weight on Other Planets
    • Your Age on Other Planets
    • Calculate Distances Between Planets
    • Interactive Solar System Model
  • Questions

Triangulum Galaxy Facts

Located in a constellation that looks like a triangle, the Triangulum Galaxy is the third-largest galaxy in our Local Group. Like its larger neighbors, the Milky Way and Andromeda Galaxy, the Triangulum Galaxy is a spiral galaxy. In images, the galaxy has arms loosely wound around the core.

triangulum galaxy facts
 Image Credit – NASA   https://www.nasa.gov/multimedia/imagegallery/image_feature_1841.html

Some galaxies, like the Milky Way, have a distinct bar shape at the core, but Triangulum does not. Instead, the Triangulum galaxy has bright star forming areas. A small cluster within the Triangulum galaxy, called NGC 604, is the largest stellar “nursery” within the Milky Way, Andromeda Galaxy and Triangulum Galaxy. NGC 604 and other variables with the Triangulum Galaxy are popular places to image because they are close, less than 3 million light years away.

When the NASA’s Swift satellite first stared taking pictures in 2007-2008, it focused on the Triangulum Galaxy. At the time, it created the “most detailed ultraviolet image of an entire galaxy ever taken.” The bright purples and blues highlight the star formation happening in the Triangulum Galaxy.

Triangulum Galaxy Profile

Designation: Messier 33 or NGC 598
Type: Spiral Galaxy
Diameter: 50,000 light-years
Distance from Earth: < 3,000,000 light-years
Mass: 50,000,000 times the mass of the Sun
Location: Triangulum Constellation
When it was discovered: 1764 (officially)
Estimated Number of Stars: 40,000,000,000 ( 40 billion )

Facts about the Triangulum Galaxy:

• It is often mistakenly called the Pinwheel Galaxy, but the official “Pinwheel Galaxy” is actually Messier 101.
• It is likely that the Triangulum Galaxy interacted with the nearby, larger Andromeda Galaxy in the past.

• There are several streams of neutral hydrogen and stars linking the two galaxies, which is why scientists think they may have interacted in the past.

•The Andromeda Galaxy and Milky Way are both larger than the Triangulum Galaxy.

•The Triangulum Galaxy may be an example of an “inside-out” galaxy formation. In this process, gas is exhausted at the galaxy’s inner core and is accumulated toward the outer edges of the galaxy. This results in an inner core and outer halo with different compositions. Scientists have observed these two distinct areas in the Triangulum Galaxy.

• An Arizona photographer Chris Schur made headlines in 2016 when he released a stunning image of the Triangulum Galaxy. This is the photo he took.


• Near the Triangulum Galaxy, there is an area that looks like three bubbles inside of each other. Scientists believe that this strange shape is the result of three different supernovae. The first supernova expanded as it exploded and formed the outer shell. Then two more smaller and quicker supernovae within created the other two smaller shells.

• Scientists have calculated that the star formation within the Triangulum Galaxy probably occurs at the rate of about half the mass of the sun per year.

• The largest stellar mass black hole ever discovered was found within the Triangulum Galaxy in 2007. The black hole, named M33 X-7, is estimated to be 15 times the mass of the sun.

• The apparent magnitude, which measures the brightness of an object as seen by a person on Earth, of the Triangulum Galaxy is 5.72. In this scale, smaller numbers are brighter, with the brightest object being the sun at -27. Objects visible to the naked eye usually have an apparent magnitude of less than 6.5. The Triangulum Galaxy should be visible to the naked eye, but it is often difficult to spot.

• The designation Messier 33 means that the Triangulum Galaxy was cataloged by French astronomer Charles Messier. It was the object number 33. His catalog is often considered the “discovery” of an object. However, the observations of an earlier Italian astronomer named Hodierna also match what the Triangulum Galaxy looks like, so it’s likely that Hodierna cataloged the galaxy first, nearly 100 years earlier.

Link/cite this page

If you use any of the content on this page in your own work, please use the code below to cite this page as the source of the content.

  • <a href="https://theplanets.org/triangulum/">Triangulum Galaxy Facts</a>

  • Stewart, Suzy. "Triangulum Galaxy Facts". The Planets. Accessed on February 4, 2023. https://theplanets.org/triangulum/.

  • Stewart, Suzy. "Triangulum Galaxy Facts". The Planets, https://theplanets.org/triangulum/. Accessed 4 February, 2023.

  • Stewart, Suzy. Triangulum Galaxy Facts. The Planets. Retrieved from https://theplanets.org/triangulum/.

Search The Universe

Popular Posts

  • Space Facts
  • Planet Facts
  • Sun Facts
  • Moon Facts
  • Types of Galaxy
  • Star Facts

Facts About The Eight Planets

  • Facts About Mercury
  • Facts About Venus
  • Facts About Earth
  • Facts About Mars
  • Facts About Jupiter
  • Facts About Saturn
  • Facts About Uranus
  • Facts About Neptune
  • About Us
  • Contact Us

© The Planets 2010 - 2023 | Privacy Policy & Affiliate Disclaimer

Copyright © 2023 ThePlanets.org | Sitemap