Server is calculating time and date for GMT time zone (London, for example). If you are from USA, you will enter to new date later. Visitors from Australia enter in new day approximately 8 hours earlier. But this problem is solved. When you are looking the page of your birthday, there is small table in upper-right corner "In my time zone its...day before or after". If you need to correct the current date, just click the relevant link.
Biorhythm is an attempt to predict various aspects (physical, emotional and intellectual) of a person's life through simple mathematical cycles. The scale is from -100 (bad) to +100 (good). On our biorhythm graph you can see not only separated 3 aspects, but the average too. Recommended source: Aschoff, Jurgen (ed.), Biological Rhythms (Handbooks of Behavioral Neurobiology). 1981.
Number of births in world on specific day is estimated value calculated from 2 tables. 1st one is birth rate in world (number of births per 1000 persons) for specific year. This value had to be multiplied to get number for world births, that's why we needed 2nd table: population in the world. These tables for years in far history was only for every 10-50th year, so the gap has to be calculated by linear interpolation. Source: UN, department of Economic and Social Affairs.
According to ISO-8601 week starts on Monday, so maybe 1st January in that year was before Monday and week belongs to the previous year (counting in weeks).
Danube river flow is calculated with average value of 2350 m³/sec at Budapest.
The start base of events is prepared from several sources, but 90% of this start base is collected from Wikipedia events. This database is continuously extended with information from news, RSS feeds, newspapers etc.
Hair grow was calculated with 0.35 mm/day speed. Heart beat rage is for 70 beat/min speed.