(Explanation to the image above: the square root of minus one is the imaginary unit, usually abbreviated by i, 2 to the power of 3 is 8, the third symbol is the summation sign, the last one of course is pi … so it reads: “i 8 sum pi” = “I ate some pie”)

# Pictures

# The Doppler Effect in Pictures

The siren of an approaching police car will sound at a higher pitch, the light of an approaching star will be shifted towards blue and a passing supersonic jet will create a violent thunder. What do these phenomenon have in common? All of them are a result of the Doppler effect. To understand how it arises, just take a look at the animations below.

**Stationary Source:** The waves coming from the source propagate symmetrically.

**Subsonic Source** (moving below sound speed): Compression of waves in direction of motion.

**Sonic Source** (moving at sound speed): Maximum compression.

**Supersonic Source** (moving beyond sound speed): Source overtakes its waves, formation of Mach cone and sonic boom.

(Pictures taken from http://www.acs.psu.edu)

# That seems like an overly harsh punishment …

# Average Size of Web Pages plus Prediction

Using data from websiteoptimization.com I plotted the development of web page sizes over the years. I also included the exponential fit:

As you can see, the 1/2 MB mark was cracked in 2009 and the 1 MB mark was cracked in 2012. Despite the seemingly random fluctuations, an exponential trend is clearly visible. The power 0.3 indicates that the web page sizes doubles about every 2.3 years. Assuming this exponential trend continues we will have these average sizes in the coming years:

2013 – ca. 1600 kb

2014 – ca. 2100 kb

2015 – ca. 2900 kb

So the 2 MB will probably be cracked in 2014 and in 2015 we will already be close to the 3 MB mark. Of course the trend is bound to flat out, but at this point there’s no telling when it will happen.

If you like more Internet analysis, check out The Internet since 1998 in Numbers.