Sunday, 9 October 2016

The Local Group Of Galaxies- Facts And Info

The Galaxy in which our solar system exists is Milky Way Galaxy and Our Galactic home is a member of Local Group of Galaxies. Local Group of Galaxies or The local Galactic Group is home of 54 galaxies. Local Group of Galaxies lies in the Virgo Super-cluster. Edwin Hubble introduced the term “The Local group” in his book The Realm of the Nebulae. There are many dwarf galaxies in this Local Group. Andromeda Galaxy is the largest galaxy in The Local Group. Andromeda Galaxy (M31) is also closest spiral galaxy to Milky Way. Milky Way is the second largest galaxy in this group. Triangulum Galaxy is the third largest galaxy in this group. All the other galaxies are the Dwarf galaxies and most of them orbit these three largest galaxies.
Image source: Wikipedia

Milky Way has sixteen satellite galaxies. Andromeda has 25 satellite galaxies and the Triangulum might have one satellite galaxy. All the other galaxies are gravitationally not orbiting any of these largest galaxies in The Local Group. Let’s take a look at dwarf galaxies orbiting the Milky Way Galaxy.

Image source: Wikipedia

Above diagram shows the closest dwarf galaxies orbiting our Milky Way Galaxy and they take billions of years to orbit it. Sagittarius dwarf is the closest dwarf galaxy to Milky Way. It is so close that it being ripped apart by Milky Way right now. Stars in the Sagittarius dwarf are being added to the Milky Way Galaxy. Formax Dwarf is the farthest away galaxy from the Milky Way Galaxy in the Local group. The two dwarf galaxies can be seen in the southern sky; they are Large Magellanic Cloud and Small Magellanic Cloud. Large Magellanic Cloud is about 160 to 170 thousand light years away and small Magellanic cloud is a bit farther at 200 thousand light years away from us. 

Large Magellanic Cloud (LMC) is the brightest galaxy in the sky. It contains several billions of stars and many are still forming in it. Small Megellanic Cloud contains several hundred million stars. These two galaxies contains many beautiful nebulae. Supernova Remnant N63A and SN 1987A are 160 to 170 thousand light years away from us and that was further extent of our Galaxy and they both lie in Large Megellanic Cloud.  Other galaxies in Local Group of galaxies are IC 10, IC 1613, Pegasus Dwarf Irregular, Leo A, Aquarius Dwarf, Cetus Dwarf, Phoenix Dwarf, Wolf-Lundmark-Melotte and Tucana Dwarf .

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