Happy Birthday to me (and one of the other 22 in the room).

Early in *As It Is On Earth*, Taylor Thatcher muses on the fact that he and his ‘brother’ Bingham share an unusual day:

*The Birthday. Our Birthday. That’s the flukiest part. Same day, same month, three years apart. How odd is that?*

*Well,…the analysis of random events always came easy to Bin, and he could tell you the odds when he was still wetting his bed. I was in my fourth year of graduate study at the University of Hartford before I finally understood Probability Theory and, by then, I had stopped caring; moved on to other things – forgetting about all that I knew to make room for what I wanted to know. All I need say is that the likelihood of having the same birthday as my younger brother depended on what’s called a “mathematical collision.” Somehow, that made enough sense of it for me.*

Quite wonderful really, this idea of a “mathematical collision”… as If Archimedes and D’Arcy Wentworth Thompson met up at a blind intersection. Or maybe it conjures that inscrutable bristly nose-haired prof in a rumpled corduroy jacket who tried to teach you math in tongue.

But, is the collision so dramatic as all that? Well,…yes and no. On the one hand, put yourself in a room with 22 others, and odds are in your favor that you’ll share a birthday with one of them. No kidding, it’s simple math…but, I’ll let you do it.

On the other hand, in certain circles this surprising result is known as The Birthday Paradox. The ‘collision’ is real. It derives from what every CIA code breaking math whiz calls The Birthday Attack, a type of cryptographic maneuver that exploits the mathematics in probability theory, that two or more people in a group of 23 will have a greater than 1 in 2 chance of sharing the same birthday. Why is this of interest to spies? Well,…it so happens that this attack “can be used to abuse communication between two or more parties.”

Yikes. I have no idea how this works, nor does Taylor Thatcher. But he seems to intuit it in his efforts to understand Bingham. So, whenever you meet up w/ someone who shares your birthday, know that you share more than just a day in the Gregorian Calendar, you also share an alignment of stars at your births,…quite literally. And do your best to communicate, knowing that your chance meeting is of note to more than just astrologers. Even, if like me, you’re a Scorpio writing a story about Libras:

*Nicole reaches out and puts the flat of her hand on Rafael’s heart. She smiles warmly at me; an affectionate smile intended to put a kindly end to things. She speaks softly, “Do you remember the Indigo Buntings, their iridescence, that brilliant blue color?”*

*I smile back. “Your birds.”*

*“It’s not the pigment in their feathers, it’s the sun’s diffraction through them. The feathers are black. It’s the starlight that makes them so beautiful.” Then turning to Miryam, she takes her hand, gently, like an elder sister acknowledging a coming of age. “Venus is his ruling planet, did you know that? Both of theirs’. Libras. The Scales of Balance.” She embraces Miryam. “Now, you should take this dark brooding boy to his starlight.”*

So I probably share a birthday with one in every 22 architects? I do share one with Frank Lloyd Wright as it happens, as does Tim Berners-Lee.