“You’re on the right track,” Dr. Michael Naughton, chair of the Department of Physics at Boston College, confirmed when contacted by The Daily Beast on Friday.
Naughton was as cautious as is any good scientist when it comes to speculation, but he ventured, “What’s not unreasonable is that footballs initially measured in a typically warm room and then brought outside and used in a 40s temperature field will have dropped one and a half to two PSI.”

This would mean that balls inflated in the warmth of the indoors to the regulation lower limit of 12.5 PSI—which the Patriots are said to prefer—would have dropped to less than 11 PSI in the first half.

That would explain why all but one of the 12 Patriot game balls came in under the limit when they were tested at the half, triggering DeflateGate and the accompanying accusations of cheating.