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How do you think stars will move with respect to each other?


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On 12/13/2019 at 10:31 PM, shdwlrd said:

Looks like satellites moving across the galactic belt on a clear night. Seriously, never realized how much the stars moved around.

For gameplay, I don't think the stars need to move. In the game maybe hundreds or couple thousand years will go by in a career. The movement in most cases is relatively small. No real need to model it.

But again, star theory may surprise us.

Agree here. Add that stars has to move in an pattern just have them move slowly in an random direction would be pointless outside of making interstellar travel a bit harder. 
Having them rotate around an central black hole works but it has to be very far away to not give us stupid high speeds and as I doubt we get more than 20 starts it would be an pretty weird formation. 

Finally I'm pretty sure we will get more stars as an dlc, this will also be easier with static stars. 
 

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25 minutes ago, magnemoe said:

Having them rotate around an central black hole works but it has to be very far away to not give us stupid high speeds

I'm confused what you mean here, black holes have the same kind of gravity as stars and they can weigh less than, around the same, or more than stars. So if all stars rotate around a black hole it would be very similar to planets orbiting a star.

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8 hours ago, mcwaffles2003 said:

I'm confused what you mean here, black holes have the same kind of gravity as stars and they can weigh less than, around the same, or more than stars. So if all stars rotate around a black hole it would be very similar to planets orbiting a star.

Indeed surely the orbital mechanics engine does care either way what they look like. It's all just bodies of mass moving in a predicable way. Let another process care about those sorts of issues.

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31 minutes ago, Incarnation of Chaos said:

It would be interesting if we could have procedural "Rogue Stars" that get flung out by the SMBH because of a close encounter, but I doubt they'd implement that because i'd imagine that's hard to make compatible with the "On Rails" system for planets and orbits.

Yeah that would most likely require N-body. Rogue Jupiters would be fun...

Imagine one is coming and will hit kerbin in 1000 years or knock it out of orbit so KSC has to develop colonies to get the population off the doomed planet :P

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3 minutes ago, mcwaffles2003 said:

Yeah that would most likely require N-body. Rogue Jupiters would be fun...

Imagine one is coming and will hit kerbin in 1000 years or knock it out of orbit so KSC has to develop colonies to get the population off the doomed planet :P

Or suppose a Brown Dwarf got captured on the edge of your systems Oort cloud, and when you finally manage to explore it further you find the ruins of an alien civilization on one of the moons which grants you additional technologies or rare materials. There's quite a number of gameplay ideas just from having the possibility present.

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On 12/13/2019 at 12:55 PM, Terwin said:

If it would take a billion years to have a 0.1% change in relative position, then I would rather go with a static system and use the saved resources for something else.

Relative position may be fixed at the scale of their separation, but relative velocity might be important for rendezvous.

On 12/13/2019 at 10:59 PM, kerbiloid said:

How can the stars move, when they are attached to the crystal sky?
Do you believe they have sky rails to roll? This is unscientific. Only planets can, because they are round.

The stars are flat!  They slide around the celestial spheres, because there's no friction in a vacuum!

Edited by Skorj
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13 hours ago, Clockwork13 said:

Stationary points. Having all the stars be moving relative to each other would be a complete nightmare to program.

Not really.  They already code for orbits, and for relative locations.  (Unless you mean every star in the background - in which case yes.)

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On 12/13/2019 at 3:55 PM, Terwin said:

How would you distinguish between a ring of stars/systems orbiting a common center of mass and a static ring of stars/systems that do not move?

How would you distinguish between a cluster of stars orbiting slowly on the outer edge of the galactic rim of a huge galaxy and a static cluster of stars?  How long would it take before there was a significant distinction?

If it would take a billion years to have a 0.1% change in relative position, then I would rather go with a static system and use the saved resources for something else.

 

There simply HAS TO  be a galactic baricenter. Not for the mentioned reasons, but for a far more simple one: travel in space is nothing but ballistic orbiting around some baricenter. Without it, what happens when you leave the Sphere of Influence of Kerbol? What happens in the void betwern Kerbol and the next star? You travel in a straight line?

I don't mind if the stars remain fixed in relation to eachother, as they drift very slowly, to the point of it being irrelevant. But a galactic baricenter has to exist, simple as that.

 

Although..... 

 

What I fear the devs are going to do, is to make the SoI of a star ending just where the next one begins, which would (unrealisticly) remove the need for both stars being under a larger baricenter that dominates gravity in the void between them. I would hate that; besides, what if there are 3 stars? What to do with the triangular empty space inbetween the intersection of three SoIs? 

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8 hours ago, Daniel Prates said:

 

There simply HAS TO  be a galactic baricenter. Not for the mentioned reasons, but for a far more simple one: travel in space is nothing but ballistic orbiting around some baricenter. Without it, what happens when you leave the Sphere of Influence of Kerbol? What happens in the void betwern Kerbol and the next star? You travel in a straight line?

I don't mind if the stars remain fixed in relation to eachother, as they drift very slowly, to the point of it being irrelevant. But a galactic baricenter has to exist, simple as that.

 

Although..... 

 

What I fear the devs are going to do, is to make the SoI of a star ending just where the next one begins, which would (unrealisticly) remove the need for both stars being under a larger baricenter that dominates gravity in the void between them. I would hate that; besides, what if there are 3 stars? What to do with the triangular empty space inbetween the intersection of three SoIs? 

This was kind of my train of thought but there's several ways I could see the kerbalverse set up. Either were in an extremely low density galaxy with all stars orbiting a barycenter/black hole or it could be in an arm of a galaxy and only the local stellar neighborhood would be made available to us. In the later scenario stellar motion would be much more toned down, as all stars would be orbiting around a distant galactic center together, than in the prior but would also seem very much like a universe with walls as the barrier to the stellar neighborhood would be a bit stark.

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21 minutes ago, mcwaffles2003 said:

This was kind of my train of thought but there's several ways I could see the kerbalverse set up. Either were in an extremely low density galaxy with all stars orbiting a barycenter/black hole or it could be in an arm of a galaxy and only the local stellar neighborhood would be made available to us. In the later scenario stellar motion would be much more toned down, as all stars would be orbiting around a distant galactic center together, than in the prior but would also seem very much like a universe with walls as the barrier to the stellar neighborhood would be a bit stark.

I don't think we need a visible, palpable, interactive baricenter for us to click, see, interact with etc. That is indeed unecessary. It would be ridiculous anyway, a map where we can interact with three (or more) close stars, then a colossal blackhole or something like that far, far away. I don't mind only seeing in the map our own star and it's neighbours.

But for calculation purposes, it will have to be taken into account. There is just no other way, interstellar travel will have to be in some body's gravity field; orbiting from one star to the next just has to be an orbit around something. If that body is not shown, fine, but the orbital mechanics will have to be modeled as if it was there.

For it not to look too weird, maybe it can be drawn in the skybox, in the direction of where it should be. I would be glad with that. 

 

Edit: that would be cool. When flying midway from two stars, looking towards your radial side and seeying that colossal black hole in the distance, feasting on the fact that it causes no computer lag whatsoever because its just a bunch of pixels, no 3d models, no nothing. It is only in the direction of what the baricenter is judged to be at by the orbit model. I guess mostly everybody would be happy with this solution!

Edited by Daniel Prates
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37 minutes ago, Daniel Prates said:

I don't think we need a visible, palpable, interactive baricenter for us to click, see, interact with etc. That is indeed unecessary. It would be ridiculous anyway, a map where we can interact with three (or more) close stars, then a colossal blackhole or something like that far, far away. I don't mind only seeing in the map our own star and it's neighbours.

I wasn't trying to suggest that the whole galaxy be interactive in the case where the kerbalverse only occupies a small arm of said galaxy. It would, in the short term at least (<2000 years), make static stars believable so no local stellar barycenter would be necessary.

In the case of the reachable stellar neighborhood being a small galaxy, having a bare barycenter might be a problem as in the current mechanic for orbits as anything gets closer to a barycenter it experiences higher g's. So unless that gets rewritten or a work around I believe there will need to be a place holder massive object, like a black hole, to be placed there. In reality at a barycenter one should feel no gravitational tug toward any body but as its currently programmed with SOIs that doesnt seem workable. Perhaps a solution will be found similar to that of the problem of rask/rusk to get around this problem.

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Even if its only 2 solar systems in the game they should still orbit a galactic core like we have in mods for kopernicus. The game needs to teach players the basics of orbital mechanics and showing them an unrealistic galaxy is worse than none at all. Even if its only one massive black hole I am ok as long as basic galactic orbital mechanics apply. If the devs do not have orbiting stars it would make me very very angry about it. 

Edited by dave1904
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7 minutes ago, dave1904 said:

showing them an unrealistic galaxy is worse than none at all.

In the case KSP is featured in an arm of a galaxy as opposed to the whole galaxy then the orbit of all nearby stars would be very similar, and would look as if all stars are static over short time periods. I would like stellar motion as well but both cases are realistic dependent on the setting they are in. 

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5 minutes ago, dave1904 said:

Even if its only 2 solar systems in the game they should still orbit a galactic core like we have in mods for kopernicus. The game needs to teach players the basics of orbital mechanics and showing them an unrealistic galaxy is worse than none at all. Even if its only one massive black hole I am ok as long as basic galactic orbital mechanics apply. If the devs do not have orbiting stars it would make me very very angry about it. 

This. Exactly.

@mcwaffles2003 you are overthinking a bit what I said. Yes, a complete gravitational field is too much, people will try to travel (fall inside) the galactic baricenter. We dont need that. And I agree, the baricenter can be a mere placeholder (but I insist the visual thing to be painted in the skybox, towards the direction it is supposed to "exist"). And the space between the stars can have limits. We need not travel higher or lower inside the galactic baricenter than necessary, parhaps there can be an altitude limit. It only gives us enough room to interestellar travel, beyond that its blocked... or something.

But it is unavoidable. The space inbetween stars HAS TO function as if it is a gravity field emanating from some baricenter. Even if at the actual baricenter there is nothing modeled. Even if we cant go anywhere near it. Even if the space modeled and traveleable ia limited to a rectangle between the stars. Even if the stars are fixed, which btw, I don't care either. I would care tho, if the interrestellar travel is a mere straight line. 

That is all my point is.

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1 minute ago, mcwaffles2003 said:

In the case KSP is featured in an arm of a galaxy as opposed to the whole galaxy then the orbit of all nearby stars would be very similar, and would look as if all stars are static over short time periods. I would like stellar motion as well but both cases are realistic dependent on the setting they are in. 

It would give players the wrong impression. 

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4 minutes ago, dave1904 said:

Even if its only 2 solar systems in the game they should still orbit a galactic core like we have in mods for kopernicus. The game needs to teach players the basics of orbital mechanics and showing them an unrealistic galaxy is worse than none at all. Even if its only one massive black hole I am ok as long as basic galactic orbital mechanics apply. If the devs do not have orbiting stars I would make me very very angry about. 

My understanding of the physics behind it is admittedly quite limited, but I'm not entirely convinced that having the stars follow planet-like Keplerian orbits is actually realistic. I was under the impression that it's an inherently more complex scenario that can only be even approximated through N-body physics, given that the combined mass of stars in a galaxy is not negligible compared to the central "body" they orbit, unlike planets orbiting a star, especially given that it's not a necessity for every galaxy to have a supermassive black hole at all. 

Point being, it might actually be less realistic to have stars following such orbits than just having them static, which would pretty much be identical from a gameplay point of view. 

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4 hours ago, Daniel Prates said:

This. Exactly.

@mcwaffles2003 you are overthinking a bit what I said. Yes, a complete gravitational field is too much, people will try to travel (fall inside) the galactic baricenter. We dont need that. And I agree, the baricenter can be a mere placeholder (but I insist the visual thing to be painted in the skybox, towards the direction it is supposed to "exist"). And the space between the stars can have limits. We need not travel higher or lower inside the galactic baricenter than necessary, parhaps there can be an altitude limit. It only gives us enough room to interestellar travel, beyond that its blocked... or something.

But it is unavoidable. The space inbetween stars HAS TO function as if it is a gravity field emanating from some baricenter. Even if at the actual baricenter there is nothing modeled. Even if we cant go anywhere near it. Even if the space modeled and traveleable ia limited to a rectangle between the stars. Even if the stars are fixed, which btw, I don't care either. I would care tho, if the interrestellar travel is a mere straight line. 

That is all my point is.

I do no if visual would be enough. I read some of your past things in this topic and now really want to be in low orbit around a black hole. LET ME DREAM!

 

Edited by dave1904
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2 minutes ago, GluttonyReaper said:

My understanding of the physics behind it is admittedly quite limited, but I'm not entirely convinced that having the stars follow planet-like Keplerian orbits is actually realistic. I was under the impression that it's an inherently more complex scenario that can only be even approximated through N-body physics, given that the combined mass of stars in a galaxy is not negligible compared to the central "body" they orbit, unlike planets orbiting a star, especially given that it's not a necessity for every galaxy to have a supermassive black hole at all. 

Point being, it might actually be less realistic to have stars following such orbits than just having them static, which would pretty much be identical from a gameplay point of view. 

You are not convinced because its not true. Its a fact that keplerian orbits don't scale on the galactic level but we still observe stars orbiting a core. Do you mean you are not convinced by dark matter? Its an issue. I do not think it would be unrealistic to give players the basic picture that stars in fact orbit a galactic core. 

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1 hour ago, dave1904 said:

It would give players the wrong impression. 

Like how they have the wrong impression about how Lagrange Points don't exist, or docking ports have supermagnets in them, or astronaut helmets are actually too large to fit through most ship doors?

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4 minutes ago, 5thHorseman said:

astronaut helmets are actually too large to fit through most ship doors?

Why do you even play the game if things like this bother you? I would think its a joke but your other 2 points are valid. 

Lagrange points would be nice to be fair but them not existing, does not give the players a wrong impression because giving the wrong impression and no impression are 2 different things. I think they should be possible but still stand by my point. 

Personally I think orbital assembly is easier with apas docking port mods because you always get the perfect rotation you planned. If the UI is improved docking should be to because rotation is important to overall craft design. 

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2 hours ago, Daniel Prates said:

This. Exactly.

@mcwaffles2003 you are overthinking a bit what I said. Yes, a complete gravitational field is too much, people will try to travel (fall inside) the galactic baricenter. We dont need that. And I agree, the baricenter can be a mere placeholder (but I insist the visual thing to be painted in the skybox, towards the direction it is supposed to "exist"). And the space between the stars can have limits. We need not travel higher or lower inside the galactic baricenter than necessary, parhaps there can be an altitude limit. It only gives us enough room to interestellar travel, beyond that its blocked... or something.

But it is unavoidable. The space inbetween stars HAS TO function as if it is a gravity field emanating from some baricenter. Even if at the actual baricenter there is nothing modeled. Even if we cant go anywhere near it. Even if the space modeled and traveleable ia limited to a rectangle between the stars. Even if the stars are fixed, which btw, I don't care either. I would care tho, if the interrestellar travel is a mere straight line. 

That is all my point is.

If the scope of the game happens to be limited to a stellar neighborhood where stars are separated by 5-10 Ly to their nearest neighbors and you want a galactic core about 100,000 Ly away which everything orbits about then travel will not be like it is between planets in a solar system, period. Travel will be essentially straight lines unless the game lasts on the order of 10s - 100s of millions of years. Which I seriously doubt

2 hours ago, dave1904 said:

It would give players the wrong impression. 

The wrong impression would be adding any noticeable curve to pathing between any neighboring stars governed by galactic orbits. That's just not how reality works, this is akin to the difference between walking to your neighbors house in a straight line vs walking along the geodesic path... At these scales there is truly no noticeable difference, period.

2 hours ago, GluttonyReaper said:

My understanding of the physics behind it is admittedly quite limited, but I'm not entirely convinced that having the stars follow planet-like Keplerian orbits is actually realistic. I was under the impression that it's an inherently more complex scenario that can only be even approximated through N-body physics, given that the combined mass of stars in a galaxy is not negligible compared to the central "body" they orbit, unlike planets orbiting a star, especially given that it's not a necessity for every galaxy to have a supermassive black hole at all. 

Point being, it might actually be less realistic to have stars following such orbits than just having them static, which would pretty much be identical from a gameplay point of view. 

This... The gravity field fluctuations of neighboring stars vastly dominates paths of travel in comparison to a galactic core about 5 orders of magnitude further away. And since the force of gravity decreases with the square of the distance an object is from it.... the actual effect the galactic center has on travel between stars is around 1/10,000,000,000 times the effect of the stars being traveled between. Even if the galactic core weighs 1,000,000 times more, gravitational force is only linearly correlated to mass, the effect is still only 1,000th that of the stars being traveled

What others are suggesting is akin to the SOI of Kerbol dominating travel between Kerbin and the Mun, its a rediculous notion as the gravitation of Kerbin and Mun have a much greater effect on ships traveling between them.

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4 minutes ago, mcwaffles2003 said:

The wrong impression would be adding any noticeable curve to pathing between any neighboring stars governed by galactic orbits. That's just not how reality works, this is akin to the difference between walking to your neighbors house in a straight line vs walking along the geodesic path... At these scales there is truly no noticeable difference, period.

That doesn't mean it should not give players the basic picture when they open the galaxy map. I do not want to be sold an illusion that the stars are orbiting a center of mass. I want them to orbit it no matter the noticeable difference. If it can be achieved with current mods there is no reason not to do it. To be fair I forget if those mods had any performance cost. Last but not least they were obviously nowhere near the scale of the milky way but neither is kerbin. 

From what I understand you just want a cluster of neighboring stars right? What difference does it make anyway? As you said the scales will be massive and I do not think they will have any major effect on calculations. If it did cost performance I would be ok with a star cluster as long as players are somehow given the picture that the cluster orbiting a core. 

 

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38 minutes ago, dave1904 said:

That doesn't mean it should not give players the basic picture when they open the galaxy map. I do not want to be sold an illusion that the stars are orbiting a center of mass. I want them to orbit it no matter the noticeable difference. If it can be achieved with current mods there is no reason not to do it. To be fair I forget if those mods had any performance cost. Last but not least they were obviously nowhere near the scale of the milky way but neither is kerbin. 

Ok, from what frame are you asking this?

Do you think an extremely small galaxy will be in this with several star systems orbiting a galactic core or are you talking about a stellar neighbor hood of an actual galaxy? If you're talking about the stellar neighborhood then having a map of an entire galaxy, literally 99.9999999% (100 systems out of 100 billion and im being extremely generous suggesting there will be 100 playable systems), would not be able to be visited and the area that could be visited would take up only several pixels.... not a very good map.  Also, as I've said, orbital motion about the galactic core in this cae would not cause any noticable curvature in the path of travel between stars. If this upsets you, you should be even more upset that Kerbol does not already affect orbital transfers from Kerbin to the Mun

main-qimg-3e91c2ae51a5587e872e0c624a8cb5

If there is a mod that you have in mind though, that is relevant to our conversation, please reference it.

51 minutes ago, dave1904 said:

From what I understand you just want a cluster of neighboring stars right? What difference does it make anyway? As you said the scales will be massive and I do not think they will have any major effect on calculations. If it did cost performance I would be ok with a star cluster as long as players are somehow given the picture that the cluster orbiting a core. 

No,  I dont have a specific want. I am proposing there are 2 scenarios to which this game can work from.

  1. There is an extremely small galaxy where all stars orbit the center, where there is a massive body. In this case it makes great sense to include orbital motion of stars, similar to that of planets about a star.
  2. There as a galaxy of considerable real size (maybe only 10 billion stars instead of 100 billion since the kerbalverse seems to be shrunk by a factor of 10) and we can only travel a small part of that galaxy, the stellar neighborhood. In this case including orbital motion would literally have no noticable effect, what so ever, unless the game plays longer than 100,000 years. A caveat to this case is that stars may move relative to one another in their stellar neighborhoods as they reside on different inclinations and their gravities effect one another as they all orbit together as a group, as can be seen in the videos I brought up earlier:
Spoiler

 

Spoiler

 

Even in this nuanced case, orbital motion while traveling between stars would create no noticeable curvature in the path between stars. For including such curvature to even start become relevant the timescale of this game would either have to be 100,000s of years at minimum or we would have to be traveling at least 1,000s of Ly. This is just like how you don't consider the curvature of the earth and look up the geodesic path to walk to your neighbors house, its complicating a very basic thing to not even improve it. If it still bugs you and there's static star systems just pretend the galactic core is out at infinity, its might as well be.

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