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Forum » SpaceEngine » General Discussions » Speed of light
Speed of light
hirak99Date: Saturday, 10.01.2015, 21:20 | Message # 1
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Is the speed of light assumed to be infinity in Space Engine?
 
Billy_MayesDate: Saturday, 10.01.2015, 22:15 | Message # 2
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No it isn't. Where did you get that idea? biggrin




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WatsisnameDate: Saturday, 10.01.2015, 22:43 | Message # 3
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No, but your camera speed is not limited to c, obviously. Otherwise exploration would be pretty slow. wink




 
Pds314Date: Sunday, 11.01.2015, 00:33 | Message # 4
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The speed of light is only taken into account in a few instances. Most circumstances don't require it to be considered.

1. Gravitational lensing - noticeable around stellar remnants (White dwarfs, Neutron stars, and black holes), space is visibly warping light around the object as if the space where a lens.

2. Redshift of far off galaxies - noticeable for brighter galaxies at distances of billions of light-years.

3. Black hole event horizons - the diameter of a black hole's event horizon is determined by its escape velocity exceeding the speed of light at that distance.

Since the motion of planets is necessarily much slower than light anyway, and the motion of stars and galaxies is not taken into account, and the camera is not intended to be an object constrained by the laws of physics, very little else uses relativistic physics.

I'm unsure if SpaceEngine takes the gravitational redshift of Neutron stars into account.

Added (10.01.2015, 23:33)
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Quote Watsisname ()
No, but your camera speed is not limited to c, obviously. Otherwise exploration would be pretty slow.

Actually, if it also took relativistic effects into account, you could explore arbitrarily fast due to time dilation. It's just that a lot of time would pass for your surroundings whilst very little would pass for you, so if you take a trip from Earth to the sun in 20 seconds, the game's internal clock would have to change by over 8 minutes. Needless to say that this "feature" is not currently implemented.


Edited by Pds314 - Sunday, 11.01.2015, 00:27
 
WatsisnameDate: Sunday, 11.01.2015, 01:17 | Message # 5
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Indeed, there is much discussion of this in the relativistic effects thread. smile SE doesn't actually model relativity yet, just emulates some of its consequences, e.g. cosmological redshift and gravitational lenses like you mentioned. To fully incorporate relativity into SE is exceptionally challenging for a single-player software, and fundamentally impossible in the context of a multiplayer game.




 
DoctorOfSpaceDate: Sunday, 11.01.2015, 04:57 | Message # 6
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Quote Watsisname ()
To fully incorporate relativity into SE is exceptionally challenging for a single-player software


Depends on how accurate or how many workarounds you would want to do. SE, as I have stated in a few posts, does have the means to accurately represent relativity with a few workarounds.

Quote Watsisname ()
and fundamentally impossible in the context of a multiplayer game.


Not impossible, just exceptionally difficult.





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WatsisnameDate: Sunday, 11.01.2015, 07:58 | Message # 7
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If we only travel via Alcubierre drives, wormholes, etc, instead of relativistic speeds in flat space-time, then yes, but then that's not what I would call a "fully relativistic game" since it leaves out the most familiar special relativistic phenomena. That's the idea I'm raising to pds -- it is fundamentally impossible to demonstrate time dilation in a real time multiplayer game because the users still physically exist in the same reference frame.

Even in a single player mode, very large time dilations (sufficient to involve galaxy evolution) begin to clash with the procedural character of the program, which is an issue SpaceEngineer has mentioned. I don't know of any practical way to work around that. So can we emulate some special relativistic effects? Sure, and I look forward to them. But I don't think we can actually have a fully relativistic program.





 
DoctorOfSpaceDate: Sunday, 11.01.2015, 08:27 | Message # 8
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Quote Watsisname ()
instead of relativistic speeds in flat space-time, then yes, but then that's not what I would call a "fully relativistic game"


I agree.

Quote Watsisname ()
since it leaves out the most familiar special relativistic phenomena. That's the idea I'm raising to pds


When I think of implementation in SE I don't think about all the universe growing old or anything like that. I think more short term workarounds that would visually represent what you would see while traveling at such speeds and not about how the rest of the universe responds, similar to the game A Slower Speed of Light. That much could already be done in engine through visual effects like color shifting and distortions alongside physics and time acceleration to match the ship's or camera's speed relative to c.

Quote Watsisname ()
Even in a single player mode, very large time dilations (sufficient to involve galaxy evolution) begin to clash with the procedural character of the program, which is an issue SpaceEngineer has mentioned. I don't know of any practical way to work around that.


To accurately do this you would need a static program like SpaceEngine and a physics simulation program like Universe Sandbox and a way to transition between them. I can't see this being done for quite a few more years in real time, let alone in a game.





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Pds314Date: Monday, 12.01.2015, 02:54 | Message # 9
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Yes. It is most definitely impossible to mess with time independently, user-by-user, in a multiplayer game, with no game-destroying side effects. If the game were built similar to Achron or something, then time dilation could be fundamentally solvable, but making it like Achron fundamentally defeats the purpose by putting the player outside of time, and thus, outside of time-dilation.
 
WatsisnameDate: Monday, 12.01.2015, 06:21 | Message # 10
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Quote DoctorOfSpace ()
I think more short term workarounds that would visually represent what you would see while traveling at such speeds and not about how the rest of the universe responds, similar to the game A Slower Speed of Light. That


Ah, I follow you. And yeah, this would be a fantastic thing to see. smile

Quote
To accurately do this you would need a static program like SpaceEngine and a physics simulation program like Universe Sandbox and a way to transition between them. I can't see this being done for quite a few more years in real time, let alone in a game.


Right. I guess it could possibly be done today, but only in a severely limited sense in the number and complexity of objects in the universe. Merging the depth and detail of SE's current procedural generation with a physics engine that allows for cosmological evolution would probably require the next generation of computing, even with supercomputing.

@pds: Hm, now you've got me curious to check out Achron's gameplay. It looks like a cool concept.





 
DoctorOfSpaceDate: Thursday, 15.01.2015, 14:53 | Message # 11
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Quote Watsisname ()
now you've got me curious to check out Achron's gameplay.


Antza and I played it a bit. The game has a great idea behind it and a really nice time structure, but the overall game is limited by bugs and it never reached its full potential sadly.





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DinoflyDate: Sunday, 18.01.2015, 21:49 | Message # 12
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Quote hirak99 ()
Is the speed of light assumed to be infinity in Space Engine?

Actually it is.
Planets and stars are at the same status and position even billion light years away, so light must be travelling at infinite speed.
 
SpyroDate: Friday, 30.01.2015, 23:17 | Message # 13
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Quote Dinofly
Planets and stars are at the same status and position even billion light years away, so light must be travelling at infinite speed.

No, just because planets and stars are at the same state no matter the distance has nothing to do with the speed of light. Its just that the further away you go, the older the light you're seeing is and you just perceive the object to be earlier in time. In reality, the object is in the same place as it was when you left it (Assuming nothing comes around and messes with it).
Just because we can see galaxies billions of years back in time doesn't mean that is the state they're in. Really, they are in totally different positions and in radically different states of evolution.

Right?





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WatsisnameDate: Saturday, 31.01.2015, 02:08 | Message # 14
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I think Dinofly was referring to how it looks in SE, not reality. Since SE considers neither large scale evolution of the universe, nor the light travel delay, everything looks the same no matter how far you view it from. One cosmological effect it does simulate is the redshift.

In a perfect simulation, it would show not only the redshift, but a time dilation of distant events (really these are the same effect), and the density and structure of the cosmos would appear different with distance as well. Look far enough and you'll see quasars, first generation stars and protogalaxies, then cosmic web formation from dark matter, and finally the CMB as the last surface of the luminous fog of plasma after the Big Bang.





 
SpyroDate: Saturday, 31.01.2015, 12:42 | Message # 15
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Oh, then in that case he's right, sometimes the Speed of Light is infinite and other times not in SE.
Why would I ever think he meant real life?!





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Edited by Spyro - Saturday, 31.01.2015, 12:42
 
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