You know, you make me think.  Stephen Hawking probably spends much of his time online.  He also probably doesn't care for the dick sucking contest that ensues (along with the upstarts trying to make a name for themselves by arguing with him) when he posts as himself.  
  
Therefore it is highly likely that he has one or more prominent alts on various social media accounts such as Reddit.  I also wouldn't be surprised to find him interested in cryptocurrency as well, if only for purely academic reasons.  He also might not like the attention that his interest in cryptocurrency would bring.  
  
In fact, I would venture to guess that many "screen names" you have interacted with in your time online may have belonged to famous and semi-famous individuals who just wanted to be judged on their arguments alone and not their reputations.  
  
I'm not even very well-known, but even I have to stop and think before I post something: "is this something too extreme for americanpegasus to say?"  You don't think I want to shit post sometimes too?