Helios calendar

Time on Earth has little meaning to someone who spends their life on another planet. While Martian calendars and clocks have existed since the 20th century, coordinating calendars for every last rock is untenable. In addition, compared to an observer outside of any gravitational well, a second on Earth is, in actuality, only .999999901895427 of a second.

The following was devised as a solution, at least in the context of the Solar System. As humanity takes the stars, no doubt a galactic calendar will eventually be developed, though the Helios Calendar is still fairly accurate on these scales.

For reworked Terran and Martian calendars, see the Tellurian Calendar and the Martian Calendar. The Helios Calendar is also sometimes referred to as 'the' Solar Calendar. This use is somewhat frowned upon since it has little in common with the standard idea of a solar calendar.

Mechanics

The Helios Calendar is fairly simple, with only one unit. It defines the Solar Month as being one full rotation of the Sun at its equator. This is about 25 days, 9 hours, 7 minutes and 12 seconds. The exact value (2,192,832 seconds) is used rather than taking the minor variations in the Sun's rotation into account, of course. Time is tracked on the sole basis of this specific measure of the sun's rotation and thus, the Helios Calendar does not proceed at exactly the same rate Terran time does.

The epoch of the Helios Calendar begins with the legendary June 15th, 763 B.C.E solar eclipse during its maximum at 08:23 GMT. According to Roman legend, Remus was conceived during this eclipse, and it is mentioned in an Assyrian tablet known as the Eponym Canon. It is perhaps the most familiar as the eclipse referred to in Amos 8: "And it shall come to pass in that day, saith the Lord GOD, that I will cause the sun to go down at noon, and I will darken the earth in the clear day." (KJV)

Example Gregorian - Helios dates

The 42,633rd Solar Month occurs about 20 days before 2201's New Year on Earth. Or simply, it's called the 633rd for short.

January 1st, Midnight GMT, 2201 is 42,633 Solar Months, 22 days, 5 hours, 12 minutes, and ~16 seconds after the begining of the epoch. The additional ~9,172 seconds (if you bothered with the math) is due to relativity - Earth experiences time about a tenth of a millionth slower than an object in 'static' space meaningfully outside any gravitational well.

February 22nd, Midnight GMT, 2222 is 42,938 Solar Months, 3 days, 7 hours, 37 minutes, and ~21 seconds after the beginning of the epoch.

The 40,000th month began on December 23rd, 2017 at 5:59:34 AM GMT. 50,000 will begin on November 10th, 2712 at 5:23:43 AM GMT.

Helios Calendar - Gregorian Calendar converter

Common Usage

The last three integral digits (938 in the 42,938th month, for example), are often used in much the same way the last two digits of a year are on Earth.

'Dot' is often considered in much the same way an hour is. At 42,133.416, the specific time of the month would be called 'Dot four-sixteen'. Individually, a dot is .001 of a month, or about 36 and a half minuts. Forty dots is roughly equivelant to a day on Earth or Mars, and outside of those two contexts, but within that of standardized time, that is the assumed meaning of 'day'.