Originally Posted by Whiternoise 
It is
- the ATLAS is huge, but i've not been to the CMS so i dunno what the comparison is..
ATLAS is much bigger in volume, although weighs a lot less.
The idea is to have two completely different designs of detector... thus, if we see the same signal in both, we know it's not some weird experimental bias.
The LHC Synchrotron, the CMS detector, the ATLAS detector, and the massive computing project that runs behind the scenes to process all the data - each of these is almost certainly in the top ten most-complicated human endeavors. In fact, the computing is probably more complicated than the other 3 put together...
Honestly, every time I learn about a new facet of this project, I get even more amazed at the level of complexity involved.
