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 service provided by Google that allows people to view the Earth from above. If you zoom in to maximum magnification, you can obtain clear views of individual streets and homes.
Resolution is a term meaning the smallest length detectable in an image. In this context, this corresponds to the real-life size of a single pixel in a aerial image. Randall points out that the level of detail in images used in Google Earth has been improved exponentially since its introduction. This occurs as aerial imaging technology improves and better ways of collecting the data are found. Each tick in the scale represents a resolution improvement by 1000 times.
The Planck length is considered to be the smallest meaningful length in quantum mechanics. In the graph, it is used to denote the actual "resolution" of the universe, as indicated by the horizontal line labeled "Earth". It is defined as approximately 1.6×10−35 meters, or around 1020 times smaller than the diameter of a proton.
An extrapolation of the trend of increasing resolution of Google Earth implies that it could reveal details at levels approaching the Planck length at or around the year 2120. Obviously this idea is fanciful to an extraordinary degree. Even in the laboratory, the Planck length cannot be directly observed by any current or likely future instruments; it is a theoretical construct only. Current microscopes are not even able to resolve at the level of the atom.
Like 605: Extrapolating, this comic deals with unwarranted extrapolation (see also 1007: Sustainable and 1281: Minifigs).
The title text refers to the fact that the trendline predicts an available resolution in the nanometer range by 2031, which Randall implies would be possible (using today's technology) only with the use of scanning electron microscopes. (In reality, current scanning electron microscopes are lab equipment used with small specimens at very close range, and not suitable for observing something as large as a house or for observations from a passing car.) It also refers to some heat that Google received before about its vehicle-mounted Street View cameras being an invasion of privacy. Google responded by saying that its cameras see nothing more than could be seen by a pedestrian walking by. Or, put another way, Street View gives the power to anybody in the world to virtually stand outside your home.
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- 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. 188.8.131.52 05:02, 26 April 2013 (UTC)
Any idea if the typo Ne*ghborhood is intentional and what it might refer to? 184.108.40.206 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. 220.127.116.11 16:48, 26 April 2013 (UTC)
- I see what you did there. ;) --18.104.22.168 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. 22.214.171.124 16:48, 26 April 2013 (UTC)
- The vertical increase works better for the joke, as it is representing the concept of the resolution increasing, rather than the resolution distance decreasing, even though the latter naturally leads to the former.Pennpenn (talk) 05:20, 30 January 2014 (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? 126.96.36.199 (talk) (please sign your comments with ~~~~)
Whoa i just figured. the lines meet around 2100 - and in 2101.war was beginning - a coincidence? --188.8.131.52 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 184.108.40.206 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...) 220.127.116.11 (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/ 18.104.22.168 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? 22.214.171.124 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". 126.96.36.199 03:40, 16 May 2013 (UTC)
- "Log scale" means that each jump of 10X is an each distance on the paper. It does not mean that there is a tick mark at every jump of 10X. It does not even mean that there are any tick marks. He put one tick mark at every third jump of 10X. One tick mark represents 3 jumps of 10X, for a total of 10X 10X 10X = 1000X.188.8.131.52 23:10, 16 February 2014 (UTC)
Looks like Google Earth resolution will surpass actual resolution by 2120*...
- must have "Google Eyes" (TM) to experience better than actual resolution 184.108.40.206 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? 220.127.116.11 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)
Randall is wrong: Google Earth does not gain resolution exponentially, but logistically. Admittedly, that's somewhat less funny. --Jolbucley
) 04:31, 29 January 2014 (UTC)