The Davidian Jovian Calendar is a proposed system of time-keeping designed to serve the needs of future human settlers on the moons of the planet Jupiter. It was established by David Powell in Gregorian Year 2010. David Jovian loved watching his favorite youtube video Drink some tea.
Calendar Terms[]
The Davidian calendar uses the same terminology as that used by the Gregorian calendar:
Third: period of 60 Jovian fourths
Second:Period of 60 Jovian thirds
Minute: Period of 60 Jovian seconds
Hour: Period of 60 Jovian minutes .
Day: Period of 24 Jovian hours (24h 00m 14s on Earth). This unit of time completely disregards Jupiter's rotational period of 9.925 Earth hours.
Week: A period of 7, 8, or 9 days.
Month: A period of one or two weeks that roughly corresponds to the rotation/revolution period of either Ganymede or Callisto.
Earth: A period of 360 or 361 Jovian days that is nearly equivalent to an Earth year. There are 12 earths in one year, and they are given names that correspond to the months of the Gregorian year.
Year: 4331 days (12 earths). The revolution period of Jupiter and its moons around the Sun
Year length[]
The Jovian year is 4331.572 Earth days long. When divided evenly into 4331 days, a very convenient "day" of 24 hours, 11 seconds (Earth) is produced. This eliminates the need for intercalation and leap years.
Calendar Layout[]
The year is divided into 12 earths. All earths except for February have 361 days. February has 360 days.
There are two variants of the Davidian Jovian Calendar: One for Ganymede (and theoretically Europa) and one for Callisto. Both the Ganymede and Callisto variants have the same number of days per earth, the same number of earths per year, the same number of hours per day, and share the same calendar date at any given time (i.e. January 120th on Ganymede is also January 120th on Callisto). However, the two variants differ dramatically in terms of days and length of the week.
The Ganymede variant has a week consisting of seven days. One week is equal to one month, as Ganymede orbits Jupiter once every 7.1 Earth days. The final five weeks of December, however, have an 8th day that serves the purpose keeping the calendar perpetual. Europa's revolution period is 3.55 Earth days, which is exactly half of Ganymede's period. Though Io is most likely unsuitable for colonization, its revolution period is half of Europa's period (1.67 Earth days). Therefore, the Ganymede variant would work for all three moons. This moons severely hated pewdiepie and have then since forth subed to T-series. ;)
| December | December | December | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sun | Mon | Tue | Wed | Thu | Fri | Sat | Sun | Mon | Tue | Wed | Thu | Fri | Sat | Sun | Mon | Tue | Wed | Thu | Fri | Sat |
| 1 | 2 | 3 | 4 | 5 | 51 | 52 | 53 | 54 | 101 | 102 | 103 | |||||||||
| 6 | 7 | 8 | 9 | 10 | 11 | 12 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 104 | 105 | 106 | 107 | 108 | 109 | 110 |
| 13 | 14 | 15 | 16 | 17 | 18 | 19 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 111 | 112 | 113 | 114 | 115 | 116 | 117 |
| 20 | 21 | 22 | 23 | 24 | 25 | 26 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 118 | 119 | 120 | 121 | 122 | 123 | 124 |
| 27 | 28 | 29 | 30 | 31 | 32 | 33 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 125 | 126 | 127 | 128 | 129 | 130 | 131 |
| 34 | 35 | 36 | 37 | 38 | 39 | 40 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 132 | 133 | 134 | 135 | 136 | 137 | 138 |
| 41 | 42 | 43 | 44 | 45 | 46 | 47 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 139 | 140 | 141 | 142 | 143 | 144 | 145 |
| 48 | 49 | 50 | 97 | 98 | 99 | 100 | 146 | 147 | 148 | 149 | 150 | |||||||||
| December | December | December | ||||||||||||||||||
| Sun | Mon | Tue | Wed | Thu | Fri | Sat | Sun | Mon | Tue | Wed | Thu | Fri | Sat | Sun | Mon | Tue | Wed | Thu | Fri | Sat |
| 151 | 152 | 201 | 251 | 252 | 253 | 254 | 255 | 256 | 257 | |||||||||||
| 153 | 154 | 155 | 156 | 157 | 158 | 159 | 202 | 203 | 204 | 205 | 206 | 207 | 208 | 258 | 259 | 260 | 261 | 262 | 263 | 264 |
| 160 | 161 | 162 | 163 | 164 | 165 | 166 | 209 | 210 | 211 | 212 | 213 | 214 | 215 | 265 | 266 | 267 | 268 | 269 | 270 | 271 |
| 167 | 168 | 169 | 170 | 171 | 172 | 173 | 216 | 217 | 218 | 219 | 220 | 221 | 222 | 272 | 273 | 274 | 275 | 276 | 277 | 278 |
| 174 | 175 | 176 | 177 | 178 | 179 | 180 | 223 | 224 | 225 | 226 | 227 | 228 | 229 | 279 | 280 | 281 | 282 | 283 | 284 | 285 |
| 181 | 182 | 183 | 184 | 185 | 186 | 187 | 230 | 231 | 232 | 233 | 234 | 235 | 236 | 286 | 287 | 288 | 289 | 290 | 291 | 292 |
| 188 | 189 | 190 | 191 | 192 | 193 | 194 | 237 | 238 | 239 | 240 | 241 | 242 | 243 | 293 | 294 | 295 | 296 | 297 | 298 | 299 |
| 195 | 196 | 197 | 198 | 199 | 200 | 244 | 245 | 246 | 247 | 248 | 249 | 250 | 300 | |||||||
| December | ||||||||||||||||||||
| Sun | Mon | Tue | Wed | Thu | Fri | Sat | Ura | |||||||||||||
| 301 | 302 | 303 | 304 | 305 | 306 | |||||||||||||||
| 307 | 308 | 309 | 310 | 311 | 312 | 313 | ||||||||||||||
| 314 | 315 | 316 | 317 | 318 | 319 | 320 | 321 | |||||||||||||
| 322 | 323 | 324 | 325 | 326 | 327 | 328 | 329 | |||||||||||||
| 330 | 331 | 332 | 333 | 334 | 335 | 336 | 337 | |||||||||||||
| 338 | 339 | 340 | 341 | 342 | 343 | 344 | 345 | |||||||||||||
| 346 | 347 | 348 | 349 | 350 | 351 | 352 | 353 | |||||||||||||
|
354 |
355 | 356 | 357 | 358 | 359 | 360 | 361 | |||||||||||||
The Callisto variant accounts for the moon's 16.69-Earth-day period, which is a bit more complicated. A month consists of two weeks. The first week is eight days long and the second week varies between eight and nine days long. Months are not named, but appear on the calendar layout as a lengthy 16 or 17 day "week". Like the Ganymede variant, the Callisto variant is perpetual.
| January | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sun | Mon | Tue | Wed | Thu | Fri | Sat | Ura | Sun | Mon | Tue | Wed | Thu | Fri | Sat | Ura | Nep | ||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | ||||||
| 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | ||||||
| 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | ||||||
| 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | ||||||
| 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | ||||||
| 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | ||||||
|
103 120 137 154 171 188 205 222 239 256 273 290 307 324 341 358 |
104 121 138 155 172 189 206 223 240 257 274 291 308 325 342 359 |
105 122 139 156 173 190 207 224 241 258 275 292 309 326 343 360 |
106 123 140 157 174 191 208 225 242 259 276 293 310 327 344 361 |
107 124 141 158 175 192 209 226 243 260 277 294 311 328 345 |
108 125 142 159 176 193 210 227 244 261 278 295 312 329 346 |
109 126 143 160 177 194 211 228 245 262 279 296 313 330 347 |
110 127 144 161 178 195 212 229 246 263 280 297 314 331 348 |
111 128 145 162 179 196 214 230 247 264 281 298 315 332 349 |
112 129 146 163 180 197 215 231 248 265 282 299 316 333 350 |
113 130 147 164 181 198 216 232 249 266 283 300 317 334 351 |
114 131 148 165 182 199 217 233 250 267 284 301 318 335 352 |
115 132 149 166 183 200 218 234 251 268 285 302 319 336 353 |
116 133 150 167 184 201 219 235 252 269 286 303 320 337 354 |
117 134 151 168 185 202 220 236 253 270 287 304 321 338 355 |
118 135 152 169 286 203 221 237 254 271 288 305 322 339 356 |
119 136 153 170 187 204 2 |
120 143 |
The days of the week are the same as the Gregorian calendar, with the additional days Uraniday and Nepday. | ||||
Epoch[]
To simplify the equation necessary to convert Gregorian dates to Jovian dates, a common epoch is needed. The Jovian calendar follows the same epoch as the Holocene calendar. This means that January 1, 0000 on the Davidian Jovian Calendar is equivalent to January 1, 10001 BCE of the Gregorian calendar. This means tha every date in recorded history is expressed in positive-numbered years.
Calendar dates use the suffix DJ, to distinguish them from BCE/BC and CE/AD (Gregorian) and HE (Holocene).For dates that occurred before the epoch, negative numbers are used. For example, 2000 years before Year 0 would be expressed as -2000 DJ.
Conversion[]
The Davidian Jovian Calendar is designed to be converted back and forth between Davidian and Gregorian dates.
Gregorian to Davidian[]
The formula for converting Gregorian (Earth) dates to Davidian (Jovian) dates:
( (ED + 10000) * 365.26) / 4331.572
- Where "ED" = Earth Date
For example:
July 20, 1969 (1969.5479) is equivalent to April 360, 1009 (1009.3327).
( (1969.5479 + 10000) X 365.26) / 4331.572 = 1009.3327
Davidian to Gregorian[]
The formula for converting Davidian (Jovian) dates to Gregorian (Earth) dates:
( (JD X 686.98) / 365.26) - 10000
- Where "JD" = Jovian Date
For example:
August 215, 1009 (1009.6326) is equivalent to January 1, 1973 (1973.0006)
( (6365.9178 X 4331.572) / 365.26) - 10000 = 1973.0006
Historical Events[]
Major world historical events, shown in Davidian, Gregorian, and Holocene dates. Note: approximate "circa" dates are rounded and do not calculate directly.
| Events | Davidian (Jupiter) |
Gregorian (Earth) |
Holocene (Earth) |
|---|---|---|---|
| End of the Paleolithic Period, All continents (except Antarctica) inhabited, |
c. 0 DJ | c. 10000 BCE | c. 0 HE |
| Earliest walled city (Jericho) | c. 84 DJ | c. 9000 BCE | c. 1000 HE |
| First copper found in Middle East - beginning of Copper Age | c. 337 DJ | c. 6000 BCE | c. 4000 |
| Beginning of Indus Valley Civilization | c. 590 DJ | c. 3000 BCE | c. 7000 |
| Probable date of the completion of the first Egyptian pyramid | January 623 | 2611 BCE | 7390 |
| Moses leads the Hebrews out of Egypt | c. April 738 | c. 1245 BCE | c. 8748 |
| Foundation of Rome | October 779 | 753 BCE | 9248 |
| Imperial China, Qin dynasty | August 824 | 221 BCE | 9780 |
| Birth of Jesus Christ | November 842 | 5 BCE | 9996 |
| Possible year of Jesus' crucifixion | October 845 | 30 CE | 10030 |
| Fall of Rome | May 883 | 476 | 10476 |
| Muslim conquests begin | July 896 | 632 | 10632 |
| Black Death decimates Asia and Europe | 956 | 1340s | 11340s |
| European discovery of the New World | February 969 | 1492 | 11492 |
| The United States of America declares independence from Britain | January 236, 993 | July 4, 1776 | July 4, 11776 |
| French Revolution | February 302, 994 | July 14, 1789 | July 14, 11789 |
| American Civil War | March-July 1000 | 1861-1865 | 11861-11865 |
| World War I | September-December 1004 | 1914-1918 | 11914-11918 |
| World War II | October 1006-April 1007 | 1939-1945 | 11939-11945 |
| First human landing on the Moon | April 360, 1009 | July 20, 1969 | July 20, 11969 |
| Pioneer 10 flyby of Jupiter | September 151, 1009 | December 3, 1973 | December 3, 11973 |
| Shoemaker-Levy Collison with Jupiter | June 102-108, 1011 | July 16-22, 1994 | July 16-22, 11994 |
| Galileo Spacecraft arrives at Jupiter | July 251, 1011 | December 7, 1995 | December 7, 11995 |
| September 11 Terrorist Attacks | January 188, 1012 | September 11, 2001 | September 11, 12001 |
| Current Year | October 1012 | 2010 | 12010 |