More data will be sent faster to Earth, thanks to this setup from the European Space Agency.
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Category: information
Just as Google recently announced that it would cease its Google Reader operations on July first, I, too, have decided to streamline my activities. Well, just my blogging activities. I think, rather than keeping all of the subject matter separated into separate categories, ergo separate blogs, I would just merge them altogether on this one.
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| via the Sartorialist |
For the few people that were in the know, I kept a separate blog on WordPress between the fall of last year and the middle of last month. Most of the content centered on policy changes or governmental influence on science and vice versa. I think there were seven posts in all. Now, I actually don’t even have a way to verify that since I deleted everything. I’ve decimated the data.
I have to say that it truly took more effort on my part to destroy all of my content than it did to put it up there in the first place. Just as James Gleick said in his 2011 book, The Information, it takes energy to erase information. You can listen to an NPR podcast here about his book instead of plowing your way through the tome just to understand the last sentence. Beware: he talks about entropy. (Hooray for the Internet! I rely on it to download my weekly supply of podcasts.) It is this entropy that is released into the universe when you erase data, when you put the work in to erase it.
The fact that you have to perform work, thus, energy, to erase data is called Landauer’s erasure principle, proposed in 1961. It is valid for all cases except for when the data are highly related, statistically speaking. Although Landauer was referring to the classical physical world, my decision to erase my other blog was more philosophically taxing than heat-generating.
The fact that you have to perform work, thus, energy, to erase data is called Landauer’s erasure principle, proposed in 1961. It is valid for all cases except for when the data are highly related, statistically speaking. Although Landauer was referring to the classical physical world, my decision to erase my other blog was more philosophically taxing than heat-generating.
In 2011, Nature published an anti-Landauer paper. In the paper, a group of scientists showed that in the quantum world, Landauer’s principle could be no longer held validity. That same year, Science reported on the proceedings of a then recent American Physical Society. Interestingly, a group at the Science meeting presented results that indicated erasing one bit of information could sometimes produce less heat than what Landauer had originally predicted. Their set-up was best schematized like this:
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| via Sciencemag.org |
They would move a bead back and forth, on a microscopic scale and using precise tools – not their hands – and measure the amount of dissipated heat each time the bead moved from 1 to 0. During some of their trials, they found that the operation released less energy than the minimum amount that Landauer predicted.
Their finding wasn’t published in a paper later on, but they did manage to have their experimental set-up accepted by the American Physical Society’s journal Physical Review E. Ostensibly, the finding they presented at that meeting wasn’t so well received by their peers. As such, Landauer’s principle, with his original predictions, still holds up in the scientific world, except for when quantum phenomena are observed.
No matter how you look at it, destroying data does require work. The exceptions would be if I ever find myself so correlated with my blog subjects so as to exclude me from Landauer’s erasure principle or if my thoughts obeyed the laws of quantum physics. But that would never happen. I blog because I can ruminate about those things that pop into my head right before I go to sleep, those things that make me think, “What if?” And isn’t that everything?
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Rio L.D., Åberg J., Renner R., Dahlsten O. & Vedral V. (2011). The thermodynamic meaning of negative entropy, Nature, 476 (7361) 476-476. DOI: 10.1038/nature10395
Jun Y. & Bechhoefer J. (2012). Virtual potentials for feedback traps, Physical Review E, 86 (6) DOI: 10.1103/PhysRevE.86.061106
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