The Bully Mnemonic & Calendar Variations

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Bully Mnemonic Topics:

• The Bully Mnemonic
• The Bully Mnemonic & Calendar Variations

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The Bully Mnemonic reminds us that there are approximately 31556928 seconds in a tropical year:

$$1\,Tropical\,Year\approx ({\color {Red}1}0{\color {Red}33}0-0.{\color {Red}4}0)\times {\color {Red}3}0{\color {Red}55}\,sec=31556928\,sec$$

Knowing the number of seconds in a tropical year can help one understand the structure of various calendars, which typically are attempting to approximate the tropical year as a multi-year average.

Julian Calendar & Gregorian Calendar

There are 86400 seconds in a day:

$${1\,Day}={24\,hours\times {\frac {60\,min}{1\,hour}}\times {\frac {60\,sec}{1\,min}}}=86400\,sec$$

The number of seconds in 365 days is:

$${365\,Days}={365\times 86400\,seconds}=31536000\,seconds$$

The number of seconds in 366 days is:

$${366\,Days}={366\times 86400\,seconds}=31622400\,seconds$$

which is 24.222% of a day less than a full tropical year:

$${\frac {1\,Tropical\,Year-365\,Days}{1\,Day}}={\frac {31556928\,sec-31536000\,sec}{86400\,sec}}$$

$${\frac {1\,Tropical\,Year-365\,Days}{1\,Day}}={\frac {20900\,sec}{86400\,sec}}=24.222...\%$$