Through our studies of the solar system this semester, we have focused particularly on the scale of the universe. Throughout the cosmos, there are countless structures that are far more massive than any we perceive. Our galaxy is held together by gravity, forming a cluster. We can also observe clusters being held together by gravity to form superclusters. Astronomers have determined that our own Milky Way Galaxy is a part of a supercluster called Laniakea.
However, some controversy exists over the definition of a stellar “wall.” There are no observable forces that bind them together – leading some astronomers to question their existence.
More recently, astronomers have discovered what they believe to be the largest structure in the observable universe – the BOSS Great Wall. This wall most likely contains over 830 galaxies and measures over a billion light years long. Furthermore, it is likely over 10,000 times the mass of the Milky Way.
Clayton Harrell - Astronomy 2110 
Clay,
Very cool! I understand that due to “dark energy” and the constant acceleration of matter away from other matter that is too far away for gravity to take effect, given the appropriate amount of time, these two object will distance themselves beyond the observable horizon. This means that in a distant future the milky way will be part of a larger galaxy that contains the mass of all the other galaxies in our local group (which will start with andromeda in ~4 billion years), but will not be able to see any other galaxies. Does this mean that once this great coalescing is finished all of the 830 galaxies will form in one super galaxy? If so is there a prediction as to how long it will be until that happens and will earth (or where we are now because earth will probably be long gone) be able to see it?
Dan
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Grader here–
YAY! So glad to see someone talking about the largest scales (my favorite) and even mentioning the Laniakea Supercluster. Check out this awesome video:
I met the guy who discovered this last summer, and my dog is named after the Shapley Supercluster!
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