08 September 2014
Fig. 1
Messier 33, the second nearest large galaxy to the Milky Way Galaxy
Credit: ESO
The VLT Survey Telescope (VST) of the European Southern Observatory (ESO) in Chile has acquired an exquisite image (Fig. 1) of the spiral galaxy Messier 33, the second closest large galaxy to our Galaxy, the Milky Way. Messier 33 is studded with dazzling star clusters and glowing clouds of gas and dust. VST’s picture of Messier 33 is among the most detailed wide-field views of this cosmic island ever obtained, as it particularly shows numerous reddish gas clouds in twirling spiral arms of the galaxy.
Messier 33, also termed NGC 598, is located about three million light-years away from Earth. It is visible in the sky among the stars of the constellation Triangulum, The Triangle. Often called the Triangulum Galaxy, it was observed by the French astronomer Charles Messier in August 1764, who listed it as the 33rd entry of his famous catalog of remarkable nebulae and star clusters. However, the Sicilian astronomer Giovanni Battista Hodierna was probably the first to document Messier 33, about a century earlier.
While the Triangulum Galaxy lies in the northern celestial hemisphere, it is just observable by the VST, which is located south of the equator. The VST is a sophisticated 2.6-meter survey telescope with a field of view that is twice as wide as the breadth of the full Moon.
Messier 33 features many star birth regions in its spiral arms, including the huge nebula NGC 604. With a diameter of almost 1,500 light-years, it is one of the largest emission nebulae in the neighborhood of our Galaxy. It is 40 times larger in size than the visible portion of Orion Nebula, one of the most prominent and closest nebulae in the Milky Way.
The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, which includes the Milky Way, the giant Andromeda Galaxy, and about 50 other smaller galaxies. Messier 33 is very faint and can be viewed with the naked eye only under very good visibility. It is considered the most distant celestial object visible to the unaided eye. Interestingly, Messier 33 is approaching our Galaxy at an enormous speed of about 100,000 km/h, but, owing to its vast distance, it will be brightening only over a very long term!
References
ESO Website
Aymen Mohamed Ibrahem