Posted by: mbuckley56 | January 13, 2009

Shape of Universe

One of the more interesting topics we touched on in class, in my opinion, was the shape of the universe. I particularly liked watching the video of many earths in all directions. I believe the strangest of these videos was the hyperbolic depiction of the universe.  Because of my fascination with the shape of the universe, I decided to research it more; but, before I discuss my findings, I’d like to start slowly.

Everyone knows that the world is round, now adays. Long gone are the times when we believed it was flat. But, my guess is, that if we asked a non-mathematician what the shape of the universe was, they would extrapolate from their knowledge of the earth and claim that the universe was spherical, or at least “round.” I, for one, believed that the universe was spherical – not that I had thought about it much, though. But, it turns out, that it is actually possible that the universe is flat. However,  there are many theories out there for the shape of the universe, and among them happens to be the spherical.

According to Kate, (I think), the prevailing idea is now that the universe is hyperbolic. This might be a biased belief because I think Kate really likes hyperbolas.  In order to understand a hyperbolic universe, it is helpful to know hyperbolic geometry. According to wikipedia, a hyperbolic universe “can be though of locally as a three-dimensional analog of an infinitely extended saddle shape.” I suppose we can all visualize this, but it seems different from the explanation of a hyperbolic universe that Kate gave in class. I think I am missing something, so could someone please address this. Maybe we talked about hyperbolic symmetries of the universe?

Apparently, scientisits are trying to figure out the shape of the universe, and they do this by looking for mirror images of microwave background radiation from different directions and places in the universe. The results of these tests so far have been to say that the spatial curvature of the universe is small, (close to flat). So, contrary to the likely popular belief, the universe may be flat (almost). Additional information on this subject can be found by reading about the Wilkinson Microwave Anisotropy Probe (WMAP), which is the device that reads this data.

One of the major concerns when discussing the shape of the universe is whether or not it is open or closed. This typically means whether or not the curvature of the universe is positive or negative, respectively.

Another important topic is whether the universe is finite or infinite. There is much literature on the subject. Search “universe is infinite” on google and see. I think the prevailing view is that it is finite.

I don’t really understand most of what I read about the shape of the universe. More math classes are needed to comprehend. Please fill in gaps.

Michael