Where, in relation to the entire universe, is the Milky Way located? (Intermediate)

I have read lately, that the estimated age of the universe is approx. 11 to 14 billion years, the Milky Way galaxy is approx. 10 billion years old, and our Sun is approx. 4 billion years old. Where, in relation to the entire Universe, is the Milky Way located, and how far in light years is the furthest detected object.

It is difficult to say where in relation to the universe the Milky Way is located since we don't think that the Universe has a center, and that (on large enough) scales it is completely homogeneous (i.e. is made of mostly the same stuff) and isotropic (i.e. doesn't change depending on the direction you look). On smaller scales the Universe contains a lot of structure (for example us!). The largest known structures are the superclusters of galaxies which form at the nodes of the filamentary-like distribution of galaxies throughout the Universe (see here). The Milky Way galaxy is found in a small group of galaxies (known as the Local Group) towards the edge of a relatively small supercluster which we call the Local Supercluster (or sometimes the Virgo Supercluster after the Virgo Cluster, the largest cluster of galaxies in it).

How far away the furthest detected object is depends on what you call an object. We detect the CMB radiation which comes from the time in the Universe when the ions and electrons first formed into atoms. That happened at a redshift of z=1000, or only about 300,000 years after the Big Bang (making it almost 13.7 billion light years away since that's how old the Universe is). The furthest galaxy we have detected however is a quasar at a redshift of about z=6, exactly how far away that is depends on your choice of cosmology (i.e. the amount of dark matter, dark energy, etc., in the Universe), but it's many billions of light years (although obviously closer than the CMB scattering surface).

This page was last updated June 27, 2015.

About the Author

Karen Masters

Karen Masters

Karen was a graduate student at Cornell from 2000-2005. She went on to work as a researcher in galaxy redshift surveys at Harvard University, and is now on the Faculty at the University of Portsmouth back in her home country of the UK. Her research lately has focused on using the morphology of galaxies to give clues to their formation and evolution. She is the Project Scientist for the Galaxy Zoo project.

Twitter:  @KarenLMasters
Website:  http://icg.port.ac.uk/~mastersk/

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