Ainia wrote:

In the last example above, the inner ring is partially obscured by the plant life and has largely worn down; but you can see a clear difference in the soil color and in the apparent fertility level, a good indicator that there is an important difference between the inner circle and the stretch of land between it and the obvious outer ring.
So more food for thought!

BTW, the difference in the plant life in the middle of the crater may be because the crater is a closed basin. Any rainwater falling in has nowhere to go and forms a lake in the crater. The water eventually evaporates and leaves salt and other minerals behind.

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Shorah Deck 15!

Your input is most gratefully welcomed! I freely admit that my background in science includes a only smattering of undergraduate geology classes and that in the years since I have not kept up with things geological. Your expertise is very helpful here.

I'm a bit partial to your second proposal simply because I tend to shy away from "coincidences" (two separate meteor impacts landing in pretty much the same place). I am wondering if you have any thoughts regarding the apparent translucent qualities of the mountains? It is quite the puzzle for my poor brain... but a most intriguing characteristic of Payiferen.

Also, I was wondering what influence the overall size of a planet/celestial body has over the strength and behavior of a meteor impact? Judging from the only map we have available to us, it appears that Reziksehv is probably smaller than Terra/Earth. And if this is the case, what would it really mean for a smaller-sized planet to have a gravity equal to that of Terra? Would this be the result of a faster spin/shorter day cycle? Would it imply that it has a heavier core than the one we have on Terra?


Since we can see far more geologically from the Payiferen pod than on the other pod continents, I have been wondering how the geological history we can observe and infer there can inform us about the rest of the pod locations, as well as the planet as a whole. For instance, can we assume or theorize that Payiferen is as barren as it is because it took the brunt of past meteorological activity? What does Dereno's lack of night mean? and Negilahn's only brief darker spell of "night"? They are both shown on opposite sides of the map (Dereno at the north, Negilahn at the south), yet the map clearly is incomplete as the Dereno continent is only partially shown and there is just the edge of an unnamed continent shown on the left. So how would the light cycles we can observe at the three pod locations translate into an axis location and overall planet size?

Judging from the D'ni numbers on the longitudinal lines, there are 13 longitudinal zones for the planet and we are being shown less than half of them on the map. In fooling around with the map in PaintShop, it looks like a full map would be about 2.6 times as wide at that particular latitude, so I guess that's a start. Judging from the curvature of the longitudinal lines, we must be seeing a portion of the northern hemisphere on the map but I'm not sure how to calculate the real "height" since we don't have any numbered latitude lines and we're probably some distance from the planet's equator in the map's view (though we may be nearer than I'm assuming since we have an arctic continent--Dereno--at the top and a tropical one--Negilahn--toward the bottom).

Anyhow, my little brain is simply bursting with questions! (This is a very interesting planet!)

(As you can see, I'm jumping at the opportunity to pick your brain!! Sincere apologies if you feel like you're being ambushed!) And BTW (in case you can't tell), I very much enjoyed your planetary geology lecture. (/me cheers and applauds)

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I take a really long time to reply to things sometimes... sorry.

Ainia wrote:

I'm a bit partial to your second proposal simply because I tend to shy away from "coincidences" (two separate meteor impacts landing in pretty much the same place).

Two craters coincidentally on top of each other may not be as far fetched as it seems. Comets or other meteorites often break up when entering the atmosphere. If two pieces happened to land in the same spot, two craters would be created. So one is technically older, but only by a few seconds. Here’s a few examples I found on the Moon and Mars:





...although maybe these examples aren’t fair. Broken up comets or other meteorites usually form chains of craters. These examples are all on old cratered surfaces and not from one object that had broken up. Most of the impact craters in our solar system were formed when the solar system was still young and the planets were sweeping up all of the extra material left over from the formation of the planets. The surfaces of the planets were all completely saturated with craters so that when a new crater formed it wasn’t just possible that it could land on top of an old crater, but it was a given that each new crater would eliminate older ones.

All that said, I favor the second theory too.

I hadn’t really considered the mountains as part of the impact structure. I’m having trouble fitting them in unless they are a ring in a very large impact basin. But then how do the smaller rings fit in? I don't believe they are additional rings of the same structure. Maybe an eroded central peak?

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I am wondering if you have any thoughts regarding the apparent translucent qualities of the mountains? It is quite the puzzle for my poor brain... but a most intriguing characteristic of Payiferen.

I like the idea that it’s some kind of atmospheric phenomenon. This is getting outside my area of knowledge so I can only guess.

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Also, I was wondering what influence the overall size of a planet/celestial body has over the strength and behavior of a meteor impact? Judging from the only map we have available to us, it appears that Reziksehv is probably smaller than Terra/Earth. And if this is the case, what would it really mean for a smaller-sized planet to have a gravity equal to that of Terra? Would this be the result of a faster spin/shorter day cycle? Would it imply that it has a heavier core than the one we have on Terra?

I like that idea, but I never really learned much about geophysics. The impact cratering process is generally the same no matter how big or how dense the planet is. There are some differences. The smaller the planet, the larger the crater a meteor will create. Ejecta from the crater won’t travel as far on a larger planet. Gravity does seem to affect when central peaks and rings start to form. You start to see central peaks in craters with diameters of about 20 km on the moon (which has about 1/6 Earth’s gravity), but they start to appear in craters with diameters of 10 km on Mars (which has about 1/3 Earth’s gravity). Craters on bigger planets often are more shallow but that might be due to more factors than just the gravity of the planet.

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Since we can see far more geologically from the Payiferen pod than on the other pod continents, I have been wondering how the geological history we can observe and infer there can inform us about the rest of the pod locations, as well as the planet as a whole. For instance, can we assume or theorize that Payiferen is as barren as it is because it took the brunt of past meteorological activity?

That could be. But then it doesn’t really take long geologically for plants to re-establish themselves and these craters look quite old to me. Maybe it’s barren here because it’s in the desert lattitudes, or in the center of the continent, or the mountains create a rainshadow.

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and Negilahn's only brief darker spell of "night"?

Now that’s a puzzle. I can’t think of anything to explain that one. Umm, maybe some of the rainforest plants are phosphorescent?

Quote:

They are both shown on opposite sides of the map (Dereno at the north, Negilahn at the south), yet the map clearly is incomplete as the Dereno continent is only partially shown and there is just the edge of an unnamed continent shown on the left. So how would the light cycles we can observe at the three pod locations translate into an axis location and overall planet size?

Judging from the D'ni numbers on the longitudinal lines, there are 13 longitudinal zones for the planet and we are being shown less than half of them on the map. In fooling around with the map in PaintShop, it looks like a full map would be about 2.6 times as wide at that particular latitude, so I guess that's a start. Judging from the curvature of the longitudinal lines, we must be seeing a portion of the northern hemisphere on the map but I'm not sure how to calculate the real "height" since we don't have any numbered latitude lines and we're probably some distance from the planet's equator in the map's view (though we may be nearer than I'm assuming since we have an arctic continent--Dereno--at the top and a tropical one--Negilahn--toward the bottom).

Wow. Sounds like you are a lot better at this kind of thing than I am. I like the idea that Dereno is near the pole and that Negilahn is near the equator.

This is fun. Maybe after we've thrashed out a geologic history for Payiferen we could start on some of the other ages. Eder Gira should be interesting.

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Shorah Deck 15!

So glad to read your response! Happy to know I didn't scare you off with my endless questions... I really like the idea of working out the geological history of Payiferen, if not Reziksehv altogether.

I'm still really puzzling over the whole daylight question. To answer your thought about luminosity in Negilahn, the last time I was there during its "night" cycle, the sky simply became dimmer somewhat and the light levels overall faded somewhat, but it was nothing near a real night--it never got truly dark. Almost as if the sun was barely below the horizon there, and relatively briefly. BTW, I like using the Zik Clock to plan my pod visits since it shows the light cycles for each of the pod locations as well as the portal times.


In re-examining the age map, in order to account for each pod's light cycles, my guess would be that the "location" for the local sun would be somewhere toward the top left corner, with Dereno being perpetually just over the horizon to the sun, Negilahn moving past the horizon only briefly each day and Payiferen being about equally over the horizon and in direct sun during the day cycle (though I'm not sure if I got the logic of this right--couldn't find an online model to help me work this out). Dereno's light is unchanging throughout its day; Negilahn's changes gradually into its brief "night" and Payiferen alone has a true sunrise and sunset. Note that on the map, the Dereno pod is 25, Negilahn is 18 and Payiferen is 13 (and Tetsonot is 6). I suppose we could make a huge assumption and consider the west-to-east arrow/line to be the equator, which could be an interesting paradox to consider in terms of the overall planet size...

Additionally, although the light levels on Dereno remain constant, one never sees the sun there; it remains just below the horizon at all times (perpetual dawn, I suppose). It is very misty and cloud-covered in Negilahn, so it's hard to know for sure how the sun moves across its skies. Payiferen has a true day/night with a dawn and sunset, with day and night appearing to be roughly equal in length (in looking at the Zik Clock) at ~8 hours/day and ~7.5 hours/night.

And it does appear as thought there are no "seasons" anywhere on Reziksehv; that the day/night cycles are unchanging at each location throughout the "year" there. So the axis must remain stable and untilted as the planet spins and orbits (I think that's what this would mean--I'm pretty rusty on this).

Out of your thoughts regarding the desert landscape in Payiferen, since we can see from the map that it's not in the middle of the continent, then perhaps it's either a desert latitude or in a rainshadow. If we go with my earlier big assumption about the equator, then I suppose it could be a desert latitude. The Payiferen pod is located in between Dereno and Negilahn latitude-wise.

If I run wild with my big assumption and earlier calculations about map size, then our pod map is showing us about 1/5 of the entire planet and would be drawn in a conic style, which would mean that land masses would appear somewhat distorted in size on the map itself.

I'm wondering if it would be possible to figure out how to do a field trip together to Payiferen and wander around the hills and dunes to see what you think of all the landscape/formations outside the pod... Not sure if it's possible, but it's an interesting thought.

The only way I've managed to explore outside the Reziksehv pods is via offline Uru using a combination of a fan-adaption of the age and a GoW tool that shall remain nameless here. I haven't yet learned whether such a visit is possible via any of the new shards (Deep Island and Gehn are the likeliest).
I agree with your thoughts regarding the desert landscape in Payiferen. Since the Sandscrit has evolved and adapted to this harsh environment, it's pretty clear that it's been this way for a very long time; long enough for the common ancestor of the Sandscrit and Urwin to have evolved in two such diverse directions. Both animals still retain their four antennae but the Sandscrit has lost his wings altogether whereas the Urwin's have simply become dwarfed and useless. Their heads and methods of consumption have diverged pretty dramatically with the Sandscrit having a pelican-like mouth pouch for scooping up sand and a gut that digests out the tiny insects from the sand. In contrast, the Urwin has baleen-like mouth plates for filtering out the Kiri (fireflies) from its huge gulps of air when it breathes back out. Both eat small insects but have very different means for consuming them.

But I'm getting off topic a bit (one of my tendencies).

Anyhow, if you get a chance to get closer views of any of these Pod areas, I would be most interested to hear your observations and theories. Maybe we can get more scientists to weigh in on this one?

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This might sound like a crazy idea...Could it simply have an "odd" planetary orbit of the solar system's sun?
(Like Pluto does in the Sol system, only more extreme?) And how would low axial tilt affect everything if it did?
One should also possibly consider the speed of the both celestial and axial rotation.

Just throwing in a few "thoughts". (Astronomy is *so* not my thing.)

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KI# 14883206 | "The truth speaks for itself, I am just the messenger." -Lyta Alexander

(Nevyn's Note: Any comments or opinions, taken whole or in part, are mine and do not reflect the stance of GoMe.)

To clarify a few things. The axial tilt of a body orbiting its star plays a part in the seasons. For example, Terra has a tilt of approx. 24.5 degrees, so it gets 4 predictable seasons (overall). A tilt of 0 degrees would mean that the seasons would be determined by something else, such as annual weather patterns, or something like that. I am not a meteorologist, or anything even remotely like that.

The speed at which a body spins determines the length of the local day, and the speed at which it orbits its star determines the length of the local year. The mass of the body determines the local gravity field, which is itself determined by the body's volume and average density.

Shorah DLordofTime!

Good to hear from you! I gather from your comments that my thinking thus far hasn't been too far off base? That if the pod planet is smaller than Terra but has the same gravity, then it would be denser and/or have a heavier core. What effect would its speed of revolution (length of day) have on gravity?

And I gather that since we see no change in day length or season at the three pod locations, then there would be no axial tilt, right? Now that I think about it a bit, I haven't noticed seasonal change in any of the D'ni ages (save for Eder Delin, which seems to be controlled by the local floating sculpture/weather machine, which probably doesn't count). Makes me wonder if the D'ni writers deliberately wrote their ages this way, perhaps not caring as a culture for seasonal change. It would kind of fit with their home life in the cavern, with its constant state. Oh those wacky guys!

Any thoughts regarding Reziksehv's relationship to its sun? I'm still trying to formulate a celestial model of all this that will explain the day/light cycles we observe at the different pods.

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The speed of revolution has less bearing on the local gravity for a smaller object than a larger one. It's all to do with how fast a point on the surface of the planet moves in relation to the center, which depends on the latitude of said point. So, find out the exact size, average density, and spin of Reziksev, and the latitude of Zik 13, and I can tell you the local gravity field, to whatever accuracy you wish.
By the way, when are you in the Cavern? I have a new avvie now.

Shorah DLordofTime,

Thanks for the additional info. BTW, are you saying that here on Terra, the gravity varies depending on latitude? If so, I'd never known that (but it sounds fascinating). Tell me more!!

Yes, I saw your thread about getting your new avvie name--glad it worked out. Can I assume that your forum name and new avvie name are the same? Does your new avvie look the same?

Haven't been in the Cavern so much as usual lately (surface life has been eating into my Cavern time). Normally, I try to get in on the weekends; Sunday evenings (KI time) are the most usual times for me to show up there. If you like, we can just make plans to meet up somewhere there soon. After all, we do need to get some age survey stuff hammered out...

What's your schedule looking like for this weekend?

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I would love to get into the Age writer's head to see their logic behind the day/night cycles in the pods.

I'm wondering just how much larger the force of gravity is compared to the centrifugal force on a person at the equator. Acceleration due to gravity is -9.8 m/s isn't it? Anyone know what the centrifugal force at the equator would be?

By the way, did you know that if you could stand at the exact center of the earth you would be weightless?

I'm going back to the pods to do a little more observing. I've checked out the pod orbiting the planet in the rings. I'll share a few things I've noticed when I've finished processing my photos.

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My Sundays are free in the KI evening. I should be around. And yes, my avvie is now DLordofTime. I do look the same. Mostly.

The gravity changes slightly, in that it is less as you approach the equator, since the Earth bulges by a considerable amount at the equator, and gravity decreases as you gain in altitude relative to the Earth's center.