In Superboy #191, Oct. 1972, the back story begins with the Birthday of Sun Boy. Several Legionnaires are throwing him a birthday party. In the comic they state it is his 11th Sola-Year. The editor makes a notation saying that a 11 Sola-Years is roughly the same as 17-18 of our years".

The comic doesn't state if this is Sun Boy's 17th or 18th birthday. If we take 17 x 365 days we get 6,205 days or if we mulitiply 18 x 365 days we get 6,570 days. Either of these could be taken as how to calculate a Sola-Year.

Is a Sola-Year some sort of planetary average for planet rotation around their suns? Is there some other type of concept which gives us a Sola-Year?

Since the party is calculated by Sola-Years and not Earth years its possible that a Sola-Year does not have to be a calculation which includes 365 days.

I'm sure the author had nothing in particular in mind beyond the editor's note of how long a Sola-Year was, so using this information let's try and fill in the gaps.

Can anyone else think of a different way to calculate the length of a Sola-Year using the Legion references above? Exactly how would you define a Sola-Year?

The 'Sola-Year' works out to be 564 -to- 598 Earth-days. A year on Mars is 684 Earth-days, so its somewhere between and Earth-Year and a Mars-Year, but greater than the average of the two. So yeah, I got nothing.

Wonderful idea for a thread!

I have no idea how to calculate these things, but I always read the editor's note to mean "somewhere between 17 and 18 years of age." Since many of the worlds the Legionnaires hail from would probably have their own calendars and rotate around their suns at different rates of speed than earth does, it makes sense that there would be some kind of UP universal standard calendar.

So, in earth terms, perhaps Sun Boy turns 17.5 years old in the story.

I suppose a possibility is that it could be some measure of age that takes into account relativistic time dilation, but I'm not alert enough at the moment to figure out how that might work.

Well, have some coffee and post again!

If my brain is working tonight, which is by no means certain, 1 Sola-Year would be the equivalent of 19 Earth months.

The significance of 19 months escapes me.

It could be some average of the solar years of the U.P. planets when the U.P. was established, something like the SDR for currency but unchanging. Time is supposed to be an invention of man and we've traditionally based it on Earth's observable rhythms, but there's no reason that couldn't be changed.

That sort of bureaucratic decision is something that might occur, but I wonder what it does to people's natural senses. Would the months and weeks on Earth also be changed? Would Christmas occur when the sun was at its low point of its cycle relative to Earth, or would it sometimes be at Spring equinox, or mid-summer? Perhaps climate control has altered the weather to the extent that monsoon season happens when they need it, not at a particular time of year, etc.

The change to sola-years would probably be quite disruptive to the population at first.