5 ms·

What bothers me even more is the precision of time they can keep the data: 13.8 billion years. Not 13.7, not 13.9 - no: they figured out 13.8 exactly. That's fa

• lvh 7y ago
  Yes, 13.8Gy is the approximate age of the universe and yes the researchers used that number. But it's not like they made this up and conveniently landed there! Turns out the biggest decay factor is nanograting and the biggest contributing physical quantity is temperature. They plotted what decay would look like on an Arrhenius plot. They both computed estimates and measured to confirm: the measurements are quite accurate. The specific claim is that they computed that at a specific temperature (462K) the medium will last 13.8Gy: their point is that it would last as long as the age of the universe at that temperature. They could've picked any other point on the time/temp scale, like "here's how long it would last at room temperature". They did not, however, simply make up a number with no justification, let alone commit straight-up academic fraud. The actual paper is here: https://www.researchgate.net/publication/297892219_Eternal_5D_data_storage_via_ultrafast-laser_writing_in_glass https://www.researchgate.net/publication/297892219_Eternal_5...
  • kragen 7y ago
    Are the error bars on the decay data they're computing from tight enough to justify three significant figures? Three significant figures doesn't seem like very much to me given the precision of modern metrology. Edit: I checked the paper and it looks like in this case the precision is actually ± one order of magnitude, so even one significant figure on the decay lifetime is overstating their precision. They can probably justify 1½ significant figures on the temperature, though.