I know you are just posting a quote, but for the record CT scanners are not calibrated with these radioactive pins, PET scanners are.

Amen. I regularly work with Intel and have early access to new cpus etc. These are targetted at HPC and are always named after a town. When it comes to building a rig for home it takes a while to decode the zoo names/codes of their procs. Even when I know what I'm looking for it takes a while. Average Joe doesn't have a chance.

So what does size actually mean for a proton. For macro scale objects we measure with some physical item that has an electrostatic interaction with the item being measured. Previously all the measurements were being made using an electron. The new measurement is using a muon. Seems like they just redefined what "size" means, i.e. muon based vs electron based. What am I missing?