Imagine the Universe.
Straight ahead of you whichever way you are facing right now at a distance of about 14.5 billion light years give or take a billion light years is the edge of the Universe. This is no ordinary edge like the edge of a table. It is rather the beginning of space and time itself -- the event horizon of the Big Bang. As we look out from where we are we also look back in time and 14.5 billion years ago give or take a billion years our Universe -- every thing that is, everything that has been and everything that will be -- was concentrated at a single point from which it burst forth into being what we see today -- our Universe, our world and ourselves. So that point 14.5 billion light years distant is the Big Bang -- the same point from which we came. And that same point is also behind you 14.5 billion light years. And it is 14.5 billion light years to your right and also to your left. And also above you and below you. It is in fact in every direction and and we are "inside" it.There is a place on the surface of the Earth that is similar in having a point that lies equidistant from it in all directions. As a matter of fact every place on the Earth is such a place and has its antipodal point. To clarify this imagine that you are standing at the North Pole. The the South Pole would be in any direction you could point along the surface of the Earth and equidistant in all directions from you. This is an analog of the geometry of space/time in our Universe. We stand at Now and the Beginning is a point equidistant in all directions.
On the Earth if you follow two lines of longitude away from the North Pole you will notice that they diverge. Two people walking different lines of longitude will appear to diverge from each other. This is what they will see and it is what you will see too if you remain at your station at the North Pole. But lines of longitude only diverge until they reach the Equator. Then they start to converge again until they meet at the South Pole. Two people walking different lines of longitude will see this as they approach within a few miles of the South Pole.
From your station at the North Pole (assuming you can somehow see over your own horizon) you too will see these longitude walkers diverge at first. And you will see them everywhere about you as they reach the South Pole. What appears to happen between the Equator and the South Pole? You might think they would appear continue to diverge and then suddenly merge when they reach the South Pole. If on the other hand you assume that light rays somehow follow lines of longitude also (this is after all necessary if our assumption that you can see over your own horizon is true) then our longitude walkers would still appear to diverge (and get smaller) as they approach the Equator. But after crossing the equator though they continue in the direction they started they will appear to get bigger (well at least wider) until when they reach the other pole they fill your horizon.
This is more like the way the geometry of of the Universe works. As you look out from here toward the Big Bang things (galaxies and clusters of galaxies) at first appear to grow smaller and space becomes larger. But after a distance analogical to the Equator in our global analogy things will start to appear larger and space smaller. The angle subtended by a given parcel of space itself thereafter will become larger and space itself like the distance between our longitude walkers as they approach the pole shrinks. Space itself shrinks to a point -- the point from which the Big Bang emerged.
Since everything -- every place and every time -- was at one point at the Big Bang our space, our time and ourselves (or the energy that coalesced into the particles that became us) is out there too. It is hidden from our view because for the first 300,000 years the universe was opaque. The end of that era is marked by a ubiquitous micro-wave background after-glow which pervades present time and has an average temperature of 30 above absolute zero -- the temperature to which the Universe has cooled (through expansion) in the intervening time.
.Return
to Tom Jonard's Cosmology page
Created June 10, 2001,
© 2001, Thomas A. Jonard