Search This Blog

Thursday, August 6, 2015

Geometry of Universe!

We are all often surprised about how vast our universe is and ask questions such as :where the universe ends? or is there any boundaries such as a concrete wall exist for universe? is it finite or infinite? But to ask these questions in right way, we may have to ask first what is the geometry or shape of the universe. The below picture describes the geometry of universe.
As referenced from WMAP-NASA:
Geometry depends on the density of the universe . If the density of the universe exceeds the critical density, then the geometry of space is closed and positively curved like the surface of a sphere. This implies that initially parallel photon paths converge slowly, eventually cross, and return back to their starting point (if the universe lasts long enough). If the density of the universe is less than the critical density, then the geometry of space is open (infinite), and negatively curved like the surface of a saddle. If the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper, and infinite in extent.
In the next post, we will discuss the current understanding on the geometry and density of universe and how it ultimately decides the fate of our universe.