How much does a memory weigh?
There's an advert for a suitcase which asks "How much does a memory weigh?". That got me thinking. The kind of memories they're talking about are things like seeing the sunset in Andalusia and so on. I reckon that you can express them reasonably well in a single sentence, or maybe two, of about ten to twenty words, that's 500-1000 characters. English has about one bit of information per character, and I'm guessing you'd start to max out alternative possible expressions put into a pool at around the 10^3 (2^10) mark. So if the total space is around 2^1000 bits, that's still about 500-1000 bits as that division is way inside the margin of error. Assuming this information needs to erase its space from a statistically random precursor, 250-500 bits need to be flipped, or (250to500)(ln2)kT Joules, assuming we're working close to room temperature, (0.0172eV)(250to500) = 4 to 9 eV. Using mass/energy equivalence, that's equivalent to a mass of 10^-35kg. So that's how much a memory weighs, I think, about the mass of a neutrino.