How to cut it in our Universe - Rounded Gaia and her bigger sister

When early people looked over the valleys and hills surrounding their neolithic camp sites, they must have wondered what lay beyond the horizon.  Sea explorers of the East Asian Empires, Europeans and perhaps the most daring of them, the Polynesian explorers, must surely have been awed by the mystery and daunted by the seemingly impenetrable line that cut its way across the view from their bows.  We may be at a new frontier today, but horizons, and their mysteries are still before us.  

Pictures of the universe are as breathtaking as they are thought-tickling.  We're at a point where, as those early explorers, we can create the first crude and coarse grained maps representing our view of the observable universe around us.  The shot here (its a CG composite) is from the work done as part of the Two Micron All Sky Survey (2MASS).

Stop and stare...  Each dot is at least a whole galaxy, the size of our own, and many of the dots are clusters of galaxies bunched together by gravity, appearing as just a single glowing speck; together creating these archipelago-like chains of light, glittering on a sea of black velvet. 

The observable universe is the blob of space around us, extending in all directions, that we are able to see with out most powerful space telescopes.  The central position in this blob is us, on the Earth.  Making up our view is the total light that has been able to reach us ever since the beginning of the universe.  As we are not able to observe things before the big bang inflation, and even with light travelling very fast, we are only able to see objects that are up to about 18 billion light years away.  Any further than that and the light from more distant objects has not reached us yet. Our descendants will be able to see further than us, but for the time being this is as far as our technology allows us to explore.  This can be thought of as a cosmic "horizon" that is in 3 dimensions - it is all around us when we look at the sky.  It is similar, and only slightly different to the Earth's 2 dimensional horizon; which is formed by objects being past the brim of our view over the Earth's curvature. 

Obviously such maps are not for use in navigation but as a way of visualizing what is around us and to convey the grand scale of the cosmos.  They are part research tools, part teaching aids and, personally, they are some of the most artistic and humbling depictions of the insignificant fragility of humanity.  What also strikes me is how round they are.  We know that horizons on Earth (or any spherical object) are round, and explorers tended to make maps that had equally rounded edges because of this.  

There is a very definite feeling of ignorance when you come across a map from the ancient world.  It is something about a map being too flat or rounded that suggests that people don't really know the land properly and are just smudging together the bits on the extremities that they don't know about so that it can look convincing at first glance.  They hope that you don't look too close or ask why there seems to be less and less details the further you leave your central point.  Maybe you just live in the most exciting part, and everywhere else is boring, flat and dull, right?  The map below is a perfect example.  

Yes - I'm sure the world really looked like that back then.  Must have been all those pesky plate tectonics moving about in the last 300 years that straightened out all the edges since then...  Antarctica thinks its Pac-Man, apparently; which is also weird. 

Modern technology is a marvel, and yet I can't help feeling that the round shape of the pictures that have been created of the universe seem very similar to what the ancient explorers drew our world as when they simply did not know what lay beyond the edges.  I wonder if our so-advanced maps of the universe will be viewed with similar quaint appreciation, hundreds of years from now?  

The ancient map above is a beautiful snapshot of our history and epistemology.  It is not diminished by its incompleteness, any more than a life is diminished by still being lived.  Instead it gives me hope.  We can learn from our ancestors.  See where they once walked to,  but had yet further to go.  They pressed on, striving for progress, so that we could be able to enjoy the knowledge we have today.  We should hope to be as brave as them - but there is more to it than that.  

Nothing would terrify me more than for there to be no more mysteries, no more for us to learn, nothing else left to discover.  I want to believe that our imperfect view of the universe is not a crack in an otherwise perfect crystal, that it is not an error or a lack of will.  Instead it is the tantalizing and limited view as seen through a keyhole.  Our eyes are pressed against it, straining to see the contents beyond, as we are urged to unlock the door and step though to what awaits us beyond the next horizon.   

Images (C) of A. Bedno and obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.