My current Erdős number is 6. I have collaborated recently with a mathematician (Jeff Lawson) whose number is 4; thus I fully expect to be “promoted” to an Erdős number of 5 within a year.

(What’s an Erdős number? Basically, it’s the mathematical equivalent of the “Bacon number”. You can read about Erdős numbers here.)

But I want to blog today about a different number that (frankly) I invented yesterday. I call it a “Google number” (GN). Here are the rules: **what is the minimum number of words, none of which are proper nouns, that you must type into Google and do a Google search, such that the first search result is about you or one of your discoveries, written by you, or is a website written/maintained by you primarily?**

I am very proud to say that my Google number is 2 (more on this later).

A Google number of 1 is very, very rare. Type “president” into Google and you get a link to President of the United States…so Obama has a Google number of 1, but this will definitely change in 2017. Type in “basketball” and you do **not** get Michael Jordan. Type in “chess” and you do **not** get Carlsen, Kasparov, or even Fischer.

Einstein has a Google number of 1: “relativity” gives you an article on relativity. James Cameron also has *GN=1*: “avatar” sends you to a James Cameron website, although you could argue that “avatar” is too close to the proper noun “Avatar” (there’s a lot of subjectivity here). I’d be inclined to give a 1 to Thomas Edison since “incandescent” goes to an article on the incandescent bulb. It’s not that easy to come up with more examples. Try it yourself.

If you think about it, even the most educated person can’t have a vocabulary of much more than 30,000 words. So logically, there can’t really be more than 30,000 or so people *in the entire world* with a Google number of 1. This is 0.0004%, or 1 in 233,333. Pretty select company. And of course the **actual** number of people with Google number 1 is much, much lower, because a lot of words are “wasted”: try searching for “harpsichord”, for example. The lead search result does **not** point to any one individual person that I can see. (Note: for simplicity, I define “Google number” as being English-specific; if we were talking about words in Spanish we might instead define a *número Google*, and so forth.)

What about a Google number of 2? In theory there could be 30,000^2 = 900,000,000 people with a 2, but in practice this is fantasy. Remember, you can’t use proper nouns. Getting a 2 is very tricky. Let’s try it with a famous person, to see how hard it is. Let’s try Stephen Hawking. “Black hole” doesn’t work; nor does “famous physicist” or “famous astrophysicist”. “Hawking radiation” is off the table (see: proper noun.) Even “grand design” doesn’t work because you get a British TV show first. “History time” is a near-miss. Finally, success: “brief history” works. *A Brief History of Time*. Hawking has a Google number of 2.

I would contend that *anyone* with *some* internet presence will have a finite Google number. For example, my colleague Jeff (with the Erdős number of 4) has a Google number of 3: just type in “heuristic geometric phase” and you will get a talk he gave in Toronto on our joint research. For all I know he may have a *lower* Google number, but it wasn’t that hard to get 3.

Now for some shameless self-promotion: my Google number is 2. Type in “metaphor loop”. I’m quite proud of this for some irrational reason.

One problem with this game is that it is fluid, ever-changing. Douglas Hofstadter could very well write a book in which “metaphor loops” were integral; soon I would find my modest paper pushed to the side. But that will happen to Obama, too, eventually, so I’m in good company. *C’est la vie.* For now, I’ll enjoy the fact that *GN(me)=2*, and I’ll await the vagaries of fate.