Which Is The Biggest Galaxy Known?

Which Is The Biggest Galaxy Known?


The largest known galaxy award goes to the truly enormous behemoth known as IC 1101. This galaxy is about 6 million light years across. To put that into some sort of perspective our nearest galaxy, Andromeda is 2.5 million light years away from us. This galaxy is so big if it were put where we are today it would encompass the whole Andromeda and Triangulum Galaxies.

You can get some idea of the size on the chart above. IC 1101 dominates the centre of the picture. If you are looking for the Milky Way it's the small dot beneath the monster. Shown below is the Milky Way when zoomed in from the picture above.


Images above by: Rhysy.net

IC 1101 probably managed to reach this size by amalgamating with other nearby galaxies. If you are looking to find it in the night sky it resides in the constellation Virgo and is part of the Abell 2029 galactic cluster. Unfortunately, as it is over a billion light years away it has a rather dim magnitude of 14.7. To find it draw a line from Arcturus in Bootes to Zeta Bootes. Then double the line in length and IC 1101 is right there. It's a dim object to see but it is possible which can be attested to by the fact that it was first discovered in 1790 by William Herschel.

On the chart below Arcturus is the star labelled 0.1 and zeta Bootes is the star labelled 3.8.


Here is a picture of the Galaxy taken by the Chandra X-ray Observatory. The image on the right is the Abell 2029 Galactic Cluster and IC 1101 can be clearly seen to dominate this cluster in the middle of the picture.

Ic1101 Abell 2029.png

Credit: X-ray: NASA/CXC/UCI/A.Lewis et al. Optical: Pal.Obs. DSS

So there you have it the biggest galaxy known is ridiculously large even by galactic standards. IC 1101 will take some beating to discover something larger but I can't wait to see it's bigger brother if one is ever found.

Find more on: Astronomy News and Science, Observing the Night Sky

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