The Internet structured as a sphere?

According to this study the structure of the Internet is a sphere:

The researchers discovered that the Internet consists of a dense, heavily connected nucleus of about 100 nodes, including Google and U.S. telecommunications giant ATT WorldNet. Surrounding this core was a region they called the 'peer-connected' component, which is able to connect to the bulk of the Internet without causing congestion in the nucleus. It is possible for data to get between any two points in the peer-connected component within about four links. The final, outermost layer is more sparsely connected, and must travel through the nucleus to reach other nodes.

Of course, as for any study worth this name, other scientists criticize how the study was shaped and - therefore - the outcomes. I tend to agree that the spherical shape seems to be coming from how the study was planned (I mean that it looks like - no matter the actual data - the shape would always be spherical), but you know, it's just me :-)