Creative Exercise: The Sovereign Dominion of Eyros

[Dr. Harry]

Eyrosian Astronomy

I really hope that I didn't miss somebody grabbing these threads already, but ...

The planet of Eyros circles a blue sun in a slightly erratic and ellipical orbit both winters and summers vary greatly from year to year (some winters are mild while others nearly snuff the life from the land). The sun appears about 75% of the size of Sol and a year is significantly longer than an Earth year.

Even if the orbit is markedly elliptical, this would accentuate the seasons and not make them vary. I suggest that the base cause of the seasons is, like Earth, due to the tilt of the axis of rotation to the plane of its orbit, and that the Sun is a variable star with a period of about (but not quite - I have a reason for this) a year. The star has periods of quiescence in which its energy output drops suficiently to make the planet experience a short term cooling trend. In the distant past this cool period corresponded with summer in Eyros, making the seasons in general mild. (As described in the ground rules.) As the "cool" period shifts over time, it is coming to align with winter in Eyros, meaning that the winters would be getting colder. While the winters might not be to the point of catastrophic, a culture used to very weak seasons might be alarmed enough about this to describe it as being almost able to "blast all life from the land".

Interestingly enough, there are some standard (Main Sequence) stars that are inherently unstable. In astronomical terms, this would be about a type A7V star -- substantially more blue than our Sun and therefore hotter, requiring that the planet be father away, thus giving rise to a longer year and a smaller apparent size for the Sun. This star would be about 10 times the luminosity of the Sun, so my first guess would put the apparent size of the sun of Eyros as about 1/2 the apparent size of the Sun in the sky. The planet would have to be about 3 times farther away from its sun than Earth is from Sol. The period would be close to 600 days. I could do the math more accurately if anyone cared.

Originally Posted by Jakar
Damn it!!! I was just going to post that the planet does not have a moon, therefore no tides or surf to speak of.

You beat me to it!!!!

You could say that there are TWO moons, each locked in opposite positions on the same orbit, thus they cancel out the tides.

The two moons would have to be in orbits that are 90 degrees apart. Two moons opposite to each other would produce exceptionally strong tides

Isn't nice to have this world of half-orcs, gnomish necromancers, and ancient magics astronomically viable? (ish)

Although ...

Why is the period of the star's variablility so gosh-darn close to the length of the year?

Why are there two moons that are held in an unstable position? What's holding them there?

 

[Arkhandus]

Welcome Dr. Harry. I don't think anything posted contradicts what you said, but Eyros does not have two moons, that guy was just saying that he was meaning to contribute that; but someone else already contributed a fact about Eyros' one moon. So Eyros has a blue sun, smaller than Sol, and one moon.

More contributions please! :^D Sado? Rystil? Mouseferatu? Twiggly? Tonguez? Anyone?

 

[Khorod]

They've all been sleeping since Saturday.

Or maybe they saw Sin City and couldn't take it

Its the Five Days Left contribution rush!

 

[Sarellion]

After Dr Harry´s post, Arkhandus should be able to post but it seems more an explanation than a contribution. So we would have a 600 day year...
Hm, I know why I never messed around with te astronomy and stayed Sol like in my homebrews.

 

[Arkhandus]

The base cause of the seasons is, like Earth, due to the tilt of the axis of rotation to the plane of its orbit, and that the Sun is a variable star with a period of about (but not quite - I have a reason for this) a year. The star has periods of quiescence in which its energy output drops suficiently to make the planet experience a short term cooling trend. In the distant past this cool period corresponded with summer in Eyros, making the seasons in general mild. As the "cool" period shifts over time, it is coming to align with winter in Eyros, meaning that the winters would be getting colder. While the winters might not be to the point of catastrophic, a culture used to very weak seasons might be alarmed enough about this to describe it as being almost able to "blast all life from the land".

This star would be about 10 times the luminosity of Sol, so the apparent size of the sun of Eyros is about 1/2 the apparent size of Sol in the sky. The planet would be about 3 times farther away from its sun than Earth is from Sol. The period would be close to 600 days.

I snipped away questions and speculative bits to get the above contribution of Dr. Harry, but didn't change anything myself. I had forgotten that we're now allowed to contribute once every 3+ posts or something.... Anyway, Eyros' sun and moon still need names, as does Eyros' main continent and the planet itself (though Eyros might be the name of either one, in which case the Sovereign Dominion was named after the continent it mostly conquered (or vice versa), but it's unlikely that Eyros is both the continent and the planet).

My contribution:

A somewhat small but growing cult on the main continent of Eyros, especially in the smaller nations there, is the Fate of One. Cultists of the Fate of One are called fateseekers or fated, and are wide-ranging individuals who preach self-empowerment and making one's own way in the world, forging one's own fate with determination and action. The cult had its roots in a small group of Nistadeeni and Ghalfaenite adventurers who visited the island Orrukar nearly 200 years ago, and leaving with what the Orrukarn gnolls would deem "a perverted deviant of our honored traditions in self-actualization". Whereas the Orrukarn disdain religion, the adventurers took their knowledge of Orrukarn philosophy and twisted it into a sort of religious cult centered on personal enlightenment and empowerment, the image of self-made men and individualists.

The Fate of One, despite its egotist teachings, actually promotes spreading the ideals and helping others achieve their greatest potential, so the Fate of One is a promoter and sponsor of many adventurers, giving them aid and quests. Fated have a simple philosophy and many actually belong to other religions as well, since fated philosophy clashes little with the fundamentals of other faiths. Fateseekers believe that either their efforts will elevate them in the eyes of the spirits or universe, or that they will transcend mortal life in one way or another by making their own way in life and achieving great things, whether by simply leaving a permanent mark on the world or ascending to a higher state of existence.

Cultists of the Fate of One tend to be very mobile and far-ranging, but keep in touch occasionally with other fateseekers, despite lacking a bureaucracy. Some Hythatians have joined the cult but tend to be seen as confused by their fellow philosophers, leading to tensions between these factions. Many fateseekers are adventurous sorts, and the most influential tend to rogues, clerics, and sorcerers. Fated clerics must choose the Luck and Travel domains.

 

[Dr. Harry]

Eyrosian Astronomy

Welcome Dr. Harry. I don't think anything posted contradicts what you said, but Eyros does not have two moons, that guy was just saying that he was meaning to contribute that; but someone else already contributed a fact about Eyros' one moon. So Eyros has a blue sun, smaller than Sol, and one moon.

More contributions please! :^D Sado? Rystil? Mouseferatu? Twiggly? Tonguez? Anyone?

Hooo-kay, this is a clarification rather than a new contribution, but I thought that I might as well do the math. The sun, which the Eyrosians call Etat, would be classified by Earth astronomers as an A7V star, which would mean that it has a surface temperature of 7800K, 1.3x that of Sol, a mass of 2.3 solar masses, a total diameter about 1.7x Sol's diameter, and a luminosity about 10x that of the Sun. In order for Eyros to have a Mediterranean-type climate, and assuming that it is located similarly on the planet, the planet would have to be 3.16 times as far away from Etat as Earth of from Sol. This would make the year about 4 Earth-Years long, and the size of Etat in the sky would be just over half the apparent size of the Sun. We could bring the planet in somewhat if high level highly reflective clouds were very common (perhaps this is a magical substance high in the atmosphere) or if the carbon dioxide level of the planet was below Earth's. If only 4/10's of Etat's radiance reaches the surface, then we could bring the planet in to 2 AU (the Earth-Sol distance) and bring the year down to 696 days (my original estimate was based on a mass 10x the Sun's not brightness 10x Sol's. My bad.)

With the protective layer (which would make the planet quite brilliant from space), then:

Etat has its peak wavelength at 371 nm (distinctly bluish)

The planet is 2 AU away from Etat.

The year is 696 Earth days long.

Etat "sleeps" (has a weak quiet period, dimming by about 5%) with a period less than half a day different from the length of the year. (This would not be strongly noticeable).

Has an apparent size about 85% the size of Sol (as observed in the sky; it is really 1.7x the radius of Sol.)

What is protecting the planet like this? Did the lizard folk druids do this over a long period of time a very long time ago to make the planet more habitable for our type of life? Did they do this by mistake? Did they do this because they ran out of some resource where they were and decided to change the climate to make their new home as comfy as their old home farther to the north?

I wonder if any of this was done in the Vale of Ur ...

A single moon will generate tidal effects unless it is very small or very far away

 

[Sarellion]

Contribution:
After the invasion, the orcish tribes merged with the orcish thralls of the elven empire and welcomed them in their tribes. Living in the empire slowly made them subject to the elven enchantments and only the crafting of the Amethyst Crown prevented that the conquering orcs fell under the sinister spell, that would have allowed the elves to regain their empire.

During the war the Valjin had with the dwarves, humans fought on both sides as hired mercenaries, getting land grants for their help. After the war humans were settled in the northern province to defend the border against invasion. The haughty and arrogant necromancers made the mistake to belittle humans and treating them as scum. The human tribes already living in the empire allied with the invasion forces and helped them in the invasion. The tribes merged with their human cousins living in the elven realm, later.

The merging of the human and orc tribes from both sides of the borders resulted in a weakening of Aekalda´s spell. In the crafting process Thanatos had to weaken former enchantments on the subjects of the spell, but thought it would only affect the elven enchantments. The result is that Thanatos ideas what a recast would do are mostly wrong.
The members of the Praes Thanatos would probably gasp at the notion that their legendary founder didn´t knew exactly what the results were, but the artifice had to be made in haste working experimental magics, with advice from imprisoned elven spellcasters and using half destroyed notes. As Aekalda´s spell is divine in nature, this mistake is understandable, considering that he doesn´t know why Aekalda´s suicide triggered such a spell, how it works exactly and what source it comes from.

It would affect eventual orcs in the Kwlloch armies and humans in the Kwlloch area but wouldn´t affect anyone living in the empire as they are not suitable targets anymore.
there is still an empathic effect affecting the inhabitants of the empire but this effect is mostly gone. They still like gnomes more than they should but they are not dancing to the gnomes music anymore.

 

[Sarellion]

Bump

Is a 730 day year ok, too? It would be easier to convert the standard year with the eyrosian year.

 

[Dr. Harry]

Bump

Is a 730 day year ok, too? It would be easier to convert the standard year with the eyrosian year.

Sure, it only involves tweaking the magical "shield" keeping all Etat's light from reaching the surface.

With the protective layer (which would make the planet quite brilliant from space), then:

The planet is 2.1 AU away from Etat.

The year is 730 Earth days long.

Has an apparent size about 81% the size of Sol (as observed in the sky; it is really 1.7x the radius of Sol.)

Should the moon have anything special about it? Shouild there be solar and lunar eclipses, or not?

 

[Sarellion]

The moon has an atmosphere, too or at least some sort of stuff that looks like fast growing forests.