Sad though it is, there are many homeless people on the streets of Manhattan. Living in the same neighbourhood for any time means one soon gets to know them, or rather recognise them, for the Gnome doubts anyone in this busy metropolis takes the time to ask their stories.
Most are quiet, lost in a world no-one who does not share their experiences can truly understand. Perhaps as in Neil Gaiman's book 'Neverwhere', they are part of some underground fantasy world, unable or unwilling to be part of the 'real' world around them.
There is one regular on the Gnome's patch though who does interact with passers-by, albeit it in a rather unconventional and, to the uninitiated, frightening way. For somebody passing by this Miles Davis lookalike will immediately be screamed at, "What the fuck do you know? I'm the professor!"
The first time this happened to the Gnome, he readily confesses he jumped out of his skin and hurried away as rapidly as possible. However, more recent sightings have been less fraught, as it soon became apparent this was a standard response to anyone who trespassed within some invisible personal space boundry and once said, no further action or communication would be forthcoming.
Now the Gnome is prepared and, if timed correctly, he can have the semblance of a conversation with the Professor. On approach a seemingly innocent scientific question can be asked. Something along the lines of "Do you not think the Hawking's theory postulating the existence of zero space with gravity high enough to absorb all light clearly solves one of the paradoxes in Einstein's theory of relativity?" and get the answer "What the fuck do you know? I'm the professor!"
And let us be honest, he is probably correct in that assumption, for the Gnome has no more idea of the answer than the next man (unless one happens to standing next to Professor Hawking of course)