## 2008/06/22 02:50:28

### brains and memory diamond

So I was browsing the tvtropes wiki, when I came upon a line in Misapplied Phlebotinum.
Sure, for a macro-scale device like that, but something as complex, intricate, and dense (in complexity/volume terms) as a human brain? That's pushing it.

Whoa-ho! I can't let a statement like that stand. Thus:

Let's improve this discussion with some math. Assuming that a human brain has 10^11 neurons (100,000,000,000), then just giving them all 39 digit serial numbers would take, of course, 10^11*2^39 = 54 zettabits or 6.871 zettabytes. Assume we use some of the address space for special characters (we could just use ASCII for the first 128 bits, making this a superset of Unicode, humorously enough.) then 39 bits of address space allows us to address a 5.49*10^11 neuron brain, or a brain with 549,755,813,888 neurons, about five and a half times more complex than a human's.

Now, assuming that the structure of our file is the serial number of a neuron followed by the numbers of the neurons it's addressing, a line feed, the next block, etc; and assuming that each neuron addresses ten others, then we get a final total of 68.71 zettabytes. The brain might be more complicated than this, and each neuron might interconnect more, but handwave handwave, let's keep moving.

Using Stross memory diamond, which has a density of 6.022*10^23 bits per 25 grams, we end up with a final encoded mass of 22.8 grams, which is 6.48 cubic centimeters of diamond.

23 grams, six and a half cubic centimeters. Roughly two orders of magnatude smaller than its organic equivilent. The brain is complicated, but it isn't magical.

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