How Heavy Is a Petabyte?
Jon Morgan writes "Whilst heaving around numerous data storage systems to sell (they weigh A LOT!), we got to wondering: How heavy is a Petabyte of data storage? Our best guess is 365KG, which is 6 million times lighter than in 1980! But is there a lighter way to store a Petabyte?"
Nobody knows exactly how much data the average human brain can hold, but one estimate is 500 to 1000 TB. If the average adult human brain weighs about 1.3 or 1.4 Kilos, then "about 2 Kilos" would hold 1 Petabyte.
and a lot bulkier than...
a few strands of DNA.
Good judgement comes from experience, and experience comes from bad judgement.
- W. Wriston, former Citibank CEO
Technically, if you don't count the hardware to read the data, we could simply remove the hard disk platters from the drive. Since most of the drive's weight is made up of the casing and read electronics, it would probably swing the data/weight ratio back in the favor of hard disks.
10,886,216.9 kilograms or 10.9 kilotons is slightly less than one Hiroshima.
So if every book in the Library Of Congress was made of TNT and you detonated them all together, the total yield would be slightly less than one very small atomic bomb. Fuck.
But you are converting mass into energy and energy into mass even in this case, although the amounts are ridiculously small in the case of chemical reactions, which is why conservation of mass is a more than reasonable approximation in chemistry. The mass is stored in the molecular binding energy of the battery's chemicals, and converted into the energy used when the battery discharges. For example, if you weighed very very carefully a bunch of hydrogen gas, a bunch of oxygen gas, and the water you got after combining the two (in a fuel cell reaction, which we can think of as the simplest sort of battery from a chemistry point of view), the water would weigh ever slightly less than the hydrogen and the oxygen, though the difference would be extremely small, since the binding energy difference of a water molecule versus that of hydrogen and oxygen molecules is only a few tens of electron volts, about 10^-35 kg or thereabouts, which amounts to a difference of about a quadrillionth of a gram for one mole of water. For nuclear reactions though, the binding energies we deal with are millions of times greater, and E=mc^2 is much more obvious. For instance, in the nuclear fusion of the two helium-3 nuclei to produce one helium-4 and two free protons, the helium-4 and the two protons weigh less than the original helium-3 nuclei by about 12.86 MeV/c^2, or about 6 milligrams less than if we started with a mole of helium-3 at the beginning of the fusion reaction.
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.