Explain xkcd: It's 'cause you're dumb.
Title text: 2031: Google defends the swiveling roof-mounted scanning electron microscopes on its Street View cars, saying they 'don't reveal anything that couldn't be seen by any pedestrian scanning your house with an electron microscope.'
Google Earth is a mapping software provided by Google that allows people to view the Earth from above. If you zoom in close enough, you can see individual streets – and as in this case, the neighborhood.
Resolution is a term meaning the smallest length detectable in an image. In this context, this would correspond to the real-life size of a single pixel in a satellite image. Higher resolutions show more detail. Randall points out that the resolution of images available to Google Earth has been improved exponentially in the past few years. Aerial imaging technology improves and better ways of collecting the data are found. Each tick in the scale represents a resolution improvement by 1000x.
The Planck length is considered to be the smallest measurable length in quantum mechanics, so it's just the maximum "resolution" of the universe. It is defined as approx. 1.6×10−35 meters, close to 1020 times smaller than the diameter of a proton. Modern microscopes are still not able to resolve an entire atom.
The comic shows how extrapolating the trend in Google Earth's resolution could hit or surpass the Planck length around the year 2100; although obviously this is questionable if this will be possible in the future. The maximum resolution of the Earth is the Planck length, and thus it remains constant as shown by the straight line denoted "Earth". Like 605: Extrapolating, it deals with unwarranted extrapolation (see also 1007: Sustainable and 1281: Minifigs).
In reality, this "resolution" is an idea from Loop quantum gravity and its younger cousins, like Causal Dynamical Triangulation.
The title text refers to the fact that the trendline predicts an available resolution in the nanometer range by 2031, which would necessitate (using today's technology) the use of scanning electron microscopes to achieve. It also refers to some heat that Google received before about its vehicle mounted cameras being an invasion of privacy. Google came back saying that nothing the cameras pick up can't be seen by a pedestrian walking by.
add a comment!
- My Neghborhood's Resolution in:
- [A chart showing the Resolution of Google Earth increasing on a logarithmic scale towards the Planck Length, with resolution on the y-axis and time in years on the x-axis.]
I'm not certain as to what the date should be, as I'm in New Zealand. I've taken one off of my current date (26th) as a precaution. Anyone who knows the right date (or right timezone) please edit it accordingly. --ZephireNZ (talk) 04:25, 26 April 2013 (UTC)
This comic arrive a day early, right?Afhoke (talk) 04:42, 26 April 2013 (UTC)
- Most likely a result of the time machine. 22.214.171.124 05:02, 26 April 2013 (UTC)
Any idea if the typo Ne*ghborhood is intentional and what it might refer to? 126.96.36.199 07:11, 26 April 2013 (UTC)
- It appears to have just been a mistake, as it's now been corrected on the panel at kxcd. 188.8.131.52 16:48, 26 April 2013 (UTC)
- I see what you did there. ;) --184.108.40.206 23:31, 26 April 2013 (UTC)
Forget electronic microscope. Where do you think they would be STORING the maps? Nearby galaxies? Other dimension? .... oh, I see: Black Mesa Research Facility is a google service company researching storage technologies. -- Hkmaly (talk) 08:13, 26 April 2013 (UTC)
Shouldn't the vertical axis be reversed? If the Planck length is the theoretical smallest length, wouldn't most readers expect the smallest value to be lowest on the vertical axis? Thus the log scale line would angle downward, more clearly indicating that the resolution lengthy is getting smaller with time. The way it it is drawn, the first impression might be that the resolution length is increasing, not decreasing. Just a suggestion. XKCD is my favorite comic because I learn something new almost every day! Matthew-e-hackman (talk) (please sign your comments with ~~~~)
- I had the same thought. Had to pause a moment to reassure myself Planck Length is a small thing. 220.127.116.11 16:48, 26 April 2013 (UTC)
Randall really likes pointing out the dangers of excessive extrapolation, doesn't he! One of his key themes. And this one is taking extremes to the extreme. Robbak (talk) 13:00, 26 April 2013 (UTC)
Representation == Reality? 18.104.22.168 (talk) (please sign your comments with ~~~~)
Whoa i just figured. the lines meet around 2100 - and in 2101.war was beginning - a coincidence? --22.214.171.124 20:25, 26 April 2013 (UTC)
- Remember, 286: All Your Base. Tryc (talk) 15:05, 13 September 2013 (UTC)
"Shouldn't the vertical axis be reversed?" I would say no. As the smallest resolvable detail shrinks, people refer to resolution as increasing, so a rising line makes sense. Maybe the axis should be denominated in pixels per meter though... Gardnertoo (talk) 15:19, 27 April 2013 (UTC)
Can somebody explain the line labeled "Earth" at the top of the diagram? Spongebog (talk)
- The resolution of actual Earth remains constant as the resolution of Google Earth approaches 126.96.36.199 04:40, 29 April 2013 (UTC)
It's also quite fun to compare the graph to the first publication of Moore's law, which had just one datapoint more but looks more or less identical to the comic. (And it still holds after 50 years... although there are signs it'll be slowing down soon...) 188.8.131.52 (talk) (please sign your comments with ~~~~)
"The images get finer as satellite imaging technology improves" - this is wrong; however, I have no idea currently how to rewite the sentence elegantly, maybe someone else does. The Google Maps/Earth finer images do not come from satellites, but are obtained by aerial photography. No commercial satellite can produce such images (maybe military ones come close - just maybe). In fact, Randall has written about that: http://what-if.xkcd.com/32/ 184.108.40.206 13:19, 29 April 2013 (UTC)
"Each tick in the scale represents a resolution improvement by 1000x." Am I being dense, or does the term "log scale" necessarily mean jumps of 10x? 220.127.116.11 20:50, 1 May 2013 (UTC)
- "A simple example [of a logarithmic scale] is a chart whose vertical or horizontal axis has equally spaced increments that are labeled 1, 10, 100, 1000, instead of 1, 2, 3, 4." Taken from wikipedia's article titled "Logarithmic scale". 18.104.22.168 03:40, 16 May 2013 (UTC)
Looks like Google Earth resolution will surpass actual resolution by 2120*...
- must have "Google Eyes" (TM) to experience better than actual resolution 22.214.171.124 17:31, 20 May 2013 (UTC)dabeansdad
Can someone please explain why the Plank length being the resolution of the universe is a "myth", as it says in the explanation? 126.96.36.199 01:22, 27 October 2013 (UTC)
- Thanks for your hint. It isn't a myth but fact in quantum mechanics. It's fixed.--Dgbrt (talk) 16:18, 27 October 2013 (UTC)