Andromeda Galaxy and Triangulum Galaxy

(Last Updated On: December 26, 2018)

Andromeda Galaxy- Introduction

Andromeda galaxy is the nearest galaxy to our galaxy Milky Way. It is a spiral galaxy. It is known also Messier31, M31 and NGC224. Its old name was Great Andromeda Nebula.

German astronomer Simon Marius give first description about Andromeda Galaxy in 15 December 1612 which based on telescopic observation.

In 2010, astronomers confirms that M31 formed due to collide two Smaller Galaxy approximately between 5 to 9 billion years ago.


andromeda galaxy
Andromeda Galaxy (Source –

Quick Facts

  • It is the largest galaxy in our local group ( local group contains our Milky way, Triangulum Galaxy and 44 other smaller galaxies).
  • It is the nearest largest galaxy to our milky way.
  • This galaxy is 2,20,000 light years across.
  • It contains approximately 1 trillion stars.
  • This galaxy is 2.5 million light years away from the earth.
  • This galaxy and Milky way galaxy are expected to collide in Giant Elliptical Galaxy  after 3.7 billion years.
  • It is the brightest galaxy in Local Group.
  • This Galaxy is not most massive than Milky Way because Milky Way contains dark matter in massive quantity.
  • It  approaching Milky Way at approximately 100-140 km/sec.
  • Scientists estimated that it contains at least one SMBH (Super Massive Black Hole) at its core.


Andromeda Galaxy
Andromeda Galaxy with moon seen from the earth (Source – Google)


It is most distant thing which is visible to naked eye. it appears more than six times wide larger than full can see it by naked eye from mid-northern latitude. You can see it perfect in last September and early October . It shines in your earthen sky in night. For good viewing, you can observe it in winter evening.


Triangulum Galaxy – Introduction

Triangulum galaxy is a Spiral Galaxy. It is known also as Messier 33 or M33, NGC  598 and Messier 101 (nick name).

Triangulum Galaxy discovered by an Italian astronomer Giovanni Battista Hodierna before 1654. But independently it discovered by Charles Messier in 25-26 August 1764 in night.


triangulum galaxy
Triangulum Galaxy (Source –

Quick Facts

  • It is the third largest galaxy in our local group after Milky Way Galaxy and Andromeda Galaxy.
  • It is referred by Pinwheel Galaxy.
  • This galaxy is located in Constellation Triangulum.
  • It is approximately 60,000 light years across (almost half diameter of the milky way galaxy).
  • This galaxy contains 40 billion stars.
  • it has mass approximately 10 billion to 40 billion solar masses.
  • Andromeda galaxy shines 8 to 9 times more than Triangulum galaxy.
  • Astronomers and scientists detected a source of water maser emission in 2005. These two water masers were detect in the opposite side of the Triangulum galaxy.
  • Triangulum galaxy is moving towards Andromeda galaxy.
  • There is clumpy steam of hydrogen gas which is linking Andromeda galaxy with Triangulum galaxy.
  • A black hole detected in the center of this galaxy in 2007 which contains 15.7 times mass of the sun. this black hole is known as M33 X-7 which is known largest stellar mass black hole.
  • M33 linked with M31 by several stream of neutral hydrogen which suggest that there past interaction took place from 2 to 8 billion years ago. And it is estimated again in 2.5 billion years in future.
Water Meson Emission

This galaxy has a own small satellite galaxy which known as Pisces Dwarf Galaxy.

triangulum galaxy
Constellation Triangulum


NASA and European scientists recorded a fingerprint of mystery molecule in this galaxy . And that is known as Diffuse Interstellar  Bands (DIBs). It is unsolved nearly 100 years. If this will be solve then we can understand and explain the formation of the planets, stars and life.


triangulum galaxy

Sometimes this galaxy looks transparent like a water spot on window.


There is a nebula (a cloud of gas and dust) in the core of this galaxy which called HII region.


triangulum galaxy
H II region (Source –
Krishan Kumar

Krishan Kumar

A Physics Enthusiast, An Entrepreneur and A Motivational Speaker, Krishan Kumar, A multi-talented personality has been portraying the role of a Science Communicator for the past 4 years. He has the utmost passion for Physics. He is truly in fact, a physicist-in-process. He is also the Co-Founder of CosmosNow (India’s First Independent Astronomy Magazine) and Fastika (A Delivery System Startup).

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