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How much memory would we need to represent a human? How would each atom be stored as? Bytes? Something more complex?

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As currently worded, this is close to being off topic, since it deals with a clearly fictional technology which will never exist. Physics can answer "what is the information content of a human being?" but not "could this be submitted to a respawning machine?" BTW, there are something like $10^{27}$ or $10^{28}$ atoms in your body, not $2\times10^9$. – Chris White Feb 10 '13 at 22:48
I'm with Chris on this, the wording needs work to get at the on-topic question in there. – dmckee Feb 10 '13 at 22:58
Uh... "if each atom was considered one byte in terms of memory?" Why this particular prior assumption? It kind of defeats the whole purpose of the question, and coverts it into a simple counting exercise which has already been answered in the comments. – dmckee Feb 11 '13 at 0:55
Plus, it would take rather more than one byte to represent the position and state of each atom accurately enough. I would suggest changing the wording to something like "how much memory would it take to represent a human, in high enough resolution that the person could, in principle, be reconstructed from the data and remain alive." Then it becomes an interesting and highly non-trivial question (to which I can probably give a reasonable answer). The "in principle" is important because it doesn't imply the existence of the probably-impossible machine required to actually do it. – Nathaniel Feb 11 '13 at 1:22
@Nathaniel But what fidelity would the copy have to have to count as the same person? Perfect copying is impossible due to quantum no-cloning, and poor copying is obviously... problematic. So you have to draw a line somewhere. Where? That is, to me, a very interesting and difficult question in its own right. Yet surely it has a huge impact on an answer to the OP's question. – Michael Brown Feb 11 '13 at 6:33
up vote 3 down vote accepted

According to the Wikipedia page on orders of magnitude (data), 2 * 10$^{45}$ bits of information are required to perfectly recreate the average-sized adult male down to the quantum level on a computer.

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This is calculated from the Bekenstein bound – endolith May 5 '13 at 23:05

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