Monday, November 22, 2010

Cosmic view

When writing about Philip and Phylis Morrison's Powers of Ten the other day I found I had made the following notation in the flyleaf, perhaps a dozen or more years ago:
Britannica
32 volumes
1000 pages per vol
1200 words per page
5 letters/wd
=200 million letters
So, 200 million letters in the 32 volume set of the Encyclopedia Britannica. Why was I making that estimate?

I can think of several possibilities. Perhaps…

1. I was making a comparison with the number of nucleotide pairs in the human DNA; that is, the number of steps -- ATTGCCCTAA, etc. -- on the double-helix. If the information on the human genome -- an arm's length of DNA in every human cell -- were written out in ordinary type, it would fill 15 sets of the Encyclopedia Britannica. Nearly 500 thick volumes of information labeled YOU.

Think of that for a moment. Fifteen 32-volume sets of the Encyclopedia Britannica in every invisibly-small cell of your body. And every time a cell reproduces, all of that information has to be transcribed correctly.

Did I say the other day that it took a semester to stretch the imagination to grasp the universe of the galaxies? It could take another semester to stretch the imagination to grasp the scale of the molecular machinery that makes our bodies work.

Or maybe…

2. I was trying to give an insight into the complexity of the human brain. There are something like 100 billion nerve cells in the brain. That's equivalent to the number of letters in 500 sets of the Britannica! Each many-fingered neuron connects to hundreds of other neurons, and each synaptic connection might be in one of many levels of excitation. I'll let you calculate the number of potential states of the human brain. We've left behind the realm of Britannica. Even talking of libraries would be insufficient.

I was marveling here recently about the amount of digital memory Google must command to store all of those 360-degree Street View images from all over the planet, all of it instantly retrievable by anyone with access to a computer and the internet. I imagined banks and banks of electronics in some cavernous building in California. Big deal! I'm sitting here right now in the college Commons and I can bring to mind street views of every place I've lived since I was three or four years old.

By the way…

3. The number of letters in 500 sets of the Britannica is about the number of stars in the Milky Way Galaxy.

And…