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JackDole
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09 Aug 2017 16:18

A-L-E-X wrote:
Source of the post But now the FOV is stuck on 120 and won't let me change it even with the console.

This is because the maximum value for FOV is 120.
If you want to change this, you have to change the parameter MaxFOV in the main-user.cfg.
 
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09 Aug 2017 16:25

JackDole wrote:
A-L-E-X wrote:
Source of the post But now the FOV is stuck on 120 and won't let me change it even with the console.

This is because the maximum value for FOV is 120.
If you want to change this, you have to change the parameter MaxFOV in the main-user.cfg.

Thanks, Jack.  Is there a way for me to use a keystroke to quickly move around and see what's behind me or do I need to drag the frame around?
Also, I see the mag limit was reduced to 5.44, is there a way for me to get it back to 7.00 and keep that saved for the next session?
 
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09 Aug 2017 16:27

This is my current view, looks like the sun is going to set soon with Jupiter to the upper left- it's very accurate as the sunset time here is in 34 min!

Screenshot - 8_9_2017 , 7_26_21 PM.jpg
 
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09 Aug 2017 16:39

One other thing, is there a way for me to make this my default screen on start up? I want to start from my current location at the current time as my "home base" from which to explore the universe.
 
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09 Aug 2017 17:04

A-L-E-X wrote:
Source of the post But let's say that our theories explaining the black hole (or big bang for that matter) as a "singularity" shows that our theories don't work on that level.

The question of what happens at black hole event horizons actually has nothing to do with the singularity.  You can replace the singularity with a small but not infinitesimal mass and it's still the same.  The properties of the event horizon and the environment around the black hole don't care about what the interior is, other than the total mass of it.  This is a consequence of Birkhoff's theorem, which you can think of as a general relativistic version of Newton's Shell Theorem.  The gravitational field outside of any spherically symmetric mass is equivalent to the same mass condensed to a singularity.

In a similar way, you can describe the properties of charged particles perfectly well by imagining them as singularities in the electric field.  You get the correct predictions as long as you don't care what happens arbitrarily close to those points. :)

With the Big Bang, you get correct predictions as long as you don't go too close to the initial instant of expansion.  Our knowledge of physics is still good up to about 10-32 seconds after the Big Bang!  What happened before then requires new physics with quantum gravitation, similarly for describing what happens very close to the center of black holes.


A-L-E-X wrote:
Source of the post But then a possible way around it was explained as follows- traveling backwards in time creates a new time line therefore no paradox happens because events can happen entirely differently than they did in the old timeline in which the traveler originated.


Maybe, but then we need new physics to explain it and a way to test it through observations.

In relativity, travelling backwards in time is the equivalent of choosing a space-like (faster than light) path through space-time rather than a time-like (slower than light) path.  For certain observers, that path will be backwards in time.  (This is basically the inverse argument for why travelling faster than light is impossible.  For certain observers, it is equivalent to going backwards in time, and thus introduces causal paradoxes).  

One could propose travelling faster than light actually is possible and avoids paradoxes by creating a new timeline, but then we again must explain how that happens and in a way which makes testable predictions.
 
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09 Aug 2017 17:21

Watsisname wrote:
A-L-E-X wrote:
Source of the post But let's say that our theories explaining the black hole (or big bang for that matter) as a "singularity" shows that our theories don't work on that level.

The question of what happens at black hole event horizons actually has nothing to do with the singularity.  You can replace the singularity with a small but not infinitesimal mass and it's still the same.  The properties of the event horizon and the environment around the black hole don't care about what the interior is, other than the total mass of it.  This is a consequence of Birkhoff's theorem, which you can think of as a general relativistic version of Newton's Shell Theorem.  The gravitational field outside of any spherically symmetric mass is equivalent to the same mass condensed to a singularity.

In a similar way, you can describe the properties of charged particles perfectly well by imagining them as singularities in the electric field.  You get the correct predictions as long as you don't care what happens arbitrarily close to those points. :)

With the Big Bang, you get correct predictions as long as you don't go too close to the initial instant of expansion.  Our knowledge of physics is still good up to about 10-32 seconds after the Big Bang!  What happened before then requires new physics with quantum gravitation, similarly for describing what happens very close to the center of black holes.



A-L-E-X wrote:
Source of the post But then a possible way around it was explained as follows- traveling backwards in time creates a new time line therefore no paradox happens because events can happen entirely differently than they did in the old timeline in which the traveler originated.


Maybe, but then we need new physics to explain it and a way to test it through observations.

In relativity, travelling backwards in time is the equivalent of choosing a space-like (faster than light) path through space-time rather than a time-like (slower than light) path.  For certain observers, that path will be backwards in time.  (This is basically the inverse argument for why travelling faster than light is impossible.  For certain observers, it is equivalent to going backwards in time, and thus introduces causal paradoxes).  

One could propose travelling faster than light actually is possible and avoids paradoxes by creating a new timeline, but then we again must explain how that happens and in a way which makes testable predictions.

Completely agree, and one of the stumbling blocks is that some of these theories predict a quantization of space-time at very small scales (5 planck lengths in one theory), and we just haven't been able to detect discrete quantities of space-time.  Space-time being continuous is what causes the singularity in the first place and if we could just get at a smaller level than what we are technologically capable of at the current time and find discrete units for space-time our singularity problems will be solved.  If space-time isn't continuous at 5 planck lengths, for example, there is no singularity because that is the minimum scale for the singularity (and thus density doesn't ever get to infinity in  the D=M/V equation since Volume can never become zero.)
This also has consequences for the Big Bang.  As Penrose proposes, the Big Bang can actually turn into a Big Bounce (perhaps this is what our "last" one actually was), as the universe "comes back empty" it reaches the 5 planck scale and becomes one dimensional (point), at that level gravity ceases to function (relativity states that three spatial dimensions are needed for gravity to be an attractive force) and the universe re-Bangs!
About the second part, other timelines, it becomes at least mathematically reasonable if F-theory is correct with its second temporal dimension.  Two dimensions of time allow other timelines to be nested (imagine time in two dimensions as two axes in a Cartesian coordinate system with the Origin being the big bang/bounce and as the universe inflates FTL the timelines emerge and separate along the second axis in time and at some point in the future, if the universe starts contracting they will converge again at the next big bang/bounce "Deflation." This at least resolves one problem I had with the Anthropic principle being involved- how do WE create timelines?  Answer is we don't- the timelines were there as the result of an emergent phenomenon from the Inflationary Period- of course this would mean that superdeterminism is correct.  Past/Present/Future would lose meaning in a sense- from a higher level anyway- since everything would be "set" from the beginning of each cycle.  The weird value of the Cosmolgical Constant might even provide a clue, as it could be slowly reducing with each cycle, and once it reaches 0, the universe would no longer re-Bang- and instead it'd have to let its "baby" universes carry on its heritage.)
By the way, this is a fascinating discussion.  We were also discussing arrows of time and I remember posting something awhile back about it being possible for different universes to have different arrows of time relative to each other (but all would still be forward with respect to the inhabitants of each universe- as if each universe was a conveyor belt going in different directions, but for the people on the belts, each belt would appear to be going forward.  You could actually construct a time machine this way if you could bridge universes, but that's another story.)  I don't necessarily believe that FTL is possible (but wormholes are that can shorten the distance) but I am intrigued by the possibility of sterile neutrinos and because they might be impervious to every force but gravity, they could travel in time.  That FTL is not possible inside our universe but might be possible outside of it (because the universe can and does expand FTL- thus the idea of the Alcubierre drive becomes possible) is also intriguing for wormhole enthusiasts.
But anyway, on a truly cosmic scale, the arrow of time itself might be relative!
By the way, what you said about choosing space-like vs time-like, isn't that what happens inside a black hole?  Space and time trade places.
Last edited by A-L-E-X on 09 Aug 2017 17:42, edited 1 time in total.
 
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09 Aug 2017 17:33

Any new physics that we theorize, not only have to explain these "special cases" but also exist in a framework in which they can also explain Relativity, Quantum Mechanics and Newtonian physics!  It'll be interesting if such a future theory incorporates gravity leaking in from another brane into its framework.  I've always believed that gravity was as different from the other three forces as time is from the other three dimensions- so there might be a connection there between gravity and time on that level  The idea that the sterile neutrino is impervious to the other three forces and only responds to gravity (if it is ever found) and that enables it to travel through time, also might provide a clue.

Newtonian physics is accurate for more than 90% of what we know, so in a sense it's the most successful theory of all, although it falls short for those less than 10% of cases (where Relativity and Quantum Mechanics step in- the very big and the very small.)
Last edited by A-L-E-X on 09 Aug 2017 17:39, edited 2 times in total.
 
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09 Aug 2017 17:36

Program was really good at simulating sunset- at 7:58 PM, so it was only 2 min off.  Problem is after sunset I get this bright yellow color on the surface- shouldn't the surface be dark now?  I can see the milky way and the ground is a bright yellow?

Screenshot - 8_9_2017 , 8_36_03 PM.jpg


Screenshot - 8_9_2017 , 8_47_44 PM.jpg
 
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XBrain130
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09 Aug 2017 17:51

A-L-E-X wrote:
Source of the post Problem is after sunset I get this bright yellow color on the surface- shouldn't the surface be dark now?  I can see the milky way and the ground is a bright yellow?

Are you on top of a city?
SpaceEngine's Italian Discord server: https://discord.gg/NhQbEbC
 
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09 Aug 2017 18:26

XBrain130 wrote:
A-L-E-X wrote:
Source of the post Problem is after sunset I get this bright yellow color on the surface- shouldn't the surface be dark now?  I can see the milky way and the ground is a bright yellow?

Are you on top of a city?

Pretty close to NYC (about 25 miles SE of it).  I got the landscape to darken by moving my mouse in a circle while the left button was pressed (I was actually trying to straighten my horizon but this happened instead lol.)
So I got the landscape to be darker, but how do I straighten my horizon?  I tried moving the mouse left right up down- everything.
Screenshot - 8_9_2017 , 9_24_06 PM.jpg
 
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09 Aug 2017 18:27

Moonrise time seems to be pretty accurate too (program depicted moonrise time to be 9:20 PM. actual moonrise is 9:14 PM, so it was off by 6 min), but I wish the moon looked bigger and not orange lol and showed the phase.  But for now I'd be happy with a straight horizon.
Last edited by A-L-E-X on 09 Aug 2017 18:43, edited 1 time in total.
 
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09 Aug 2017 18:33

Okay I straightened out the horizon but it was incredibly difficult to do so (I almost sprained my wrist twisting it around with the mouse!)  Is there any way to lock the program so that the horizon always remains straight?  Or a quick option to instantly straighten the horizon without using the mouse?
Also, doesn't the below image look a bit odd with all those stars near the center of the image and the edges being so dark?  Is this a function of map distortion because of the projection used to depict a spherical sky on a flat surface (I see it in Stellarium too at wide angles but it typically only kicks in at FOVs larger than 180 degrees in Stellarium.)

Screenshot - 8_9_2017 , 9_31_42 PM.jpg
 
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Watsisname
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09 Aug 2017 21:12

A-L-E-X wrote:
Source of the post Any new physics that we theorize, not only have to explain these "special cases" but also exist in a framework in which they can also explain Relativity, Quantum Mechanics and Newtonian physics!

This is such a great comment.  Many people think that theories get replaced, or that what we think we know now will be irrelevant in the future.  But indeed any new model or theory must explain/predict the very same observations that the old ones did.  GR reduces to Newton at slow speeds and weak fields, and whatever future theories of Quantum Gravity must do the same. :)
 
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09 Aug 2017 21:33

Watsisname wrote:
A-L-E-X wrote:
Source of the post Any new physics that we theorize, not only have to explain these "special cases" but also exist in a framework in which they can also explain Relativity, Quantum Mechanics and Newtonian physics!

This is such a great comment.  Many people think that theories get replaced, or that what we think we know now will be irrelevant in the future.  But indeed any new model or theory must explain/predict the very same observations that the old ones did.  GR reduces to Newton at slow speeds and weak fields, and whatever future theories of Quantum Gravity must do the same. :)

Thanks! :)   I like to picture them in my head like Venn diagrams.  Newtonian physics takes up a large slice of what we know about the universe, but Relativity and Quantum Mechanics include it and some areas that are "outside" of it.  We still have the frontiers of science to explore and hopefully come up with an even larger more universal theory that includes the Venn diagrams of what came before it, plus the new areas that we have yet to explore!  The real challenge will be to create a Venn diagram that unifies Relativity and Quantum Mechanics- from where we shall obtain Quantum Gravity!
 
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Watsisname
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09 Aug 2017 21:55

A-L-E-X wrote:
Source of the post By the way, what you said about choosing space-like vs time-like, isn't that what happens inside a black hole?  Space and time trade places.

Inside the horizon, the radial coordinate (towards the singularity) becomes time-like, and the time coordinate becomes space-like.  The effect of this is that the only allowed (time-like) paths that you can take are inward -- towards the singularity.  If you want to move outward (or even stay still!), you would have to follow a space-like path, and this is not allowed.

Or my other favorite way to put it: Once inside the horizon, the singularity lies in the direction of the future.  You cannot avoid it, in much the same way that you cannot avoid next Tuesday.

This also happens to the space-time outside the horizon of rotating black holes.  Inside a certain distance (the "Static Limit"), the azimuthal (longitude) coordinate becomes time-like.  So you are forced to move in the same direction that the black hole is spinning.  Moving against the spin is not allowed.

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