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Watsisname
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31 Aug 2017 15:00

spaceguy wrote:
Source of the post What's the type of fluid flow in Jupiter's atmosphere that creates these clouds formations?

I think it's just called turbulent flow, which is what leads to the vortices and mixing.  The other type of flow is "laminar", where the fluid flows in smooth sheets without breaking up into turbulence.
 
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31 Aug 2017 15:04

Watsisname wrote:
spaceguy wrote:
Source of the post What's the type of fluid flow in Jupiter's atmosphere that creates these clouds formations?

I think it's just called turbulent flow, which is what leads to the vortices and mixing.  The other type of flow is "laminar", where the fluid flows in smooth sheets without breaking up into turbulence.

Wat are you also seeing issues with the "e" patch with regards to textures? I miss my clouds and I miss my rippling waves :(
 
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31 Aug 2017 15:06

Watsisname wrote:
midtskogen wrote:
Source of the post Assuming that the ship has all the energy needed, how is it supposed to supply the energy to sustain the bubble if nothing can reach the front horizon?

Consider a related question: "how is a black hole able to sustain an event horizon around itself if nothing can reach the horizon from within -- or even leave the singularity in the first place?"

That's a common way to answer this question and make it seem like it isn't an issue, but there's actually a lot of subtlety to it.  In fact, according to the outside universe, the inside of a black hole doesn't exist.  All events at the horizon take place infinitely far in the future, and events in the interior are never observed.

If we're outside, the properties of the event horizon and external gravitational field appear because to us there is a spherical shell of mass frozen on the horizon, and the field from a spherical shell is the same on the outside as if it were a singularity instead.  Only when we shift into the reference frame which is falling into it do we discover that the mass has collapsed to singularity and the space-time extends into that region.

So the black hole isn't really "sustaining" its event horizon from a singularity at all.  There is no contact between the two.  It just turns out that the gravitational field according to observers inside and outside happen to exactly match up, even though they have totally different ideas of where the mass is located.

General relativity suggests in this case to take a shortcut.  Say that the mass "really is" at the central singularity, and then use the field equations to determine the geometry of the surrounding space-time.  The equations insist that you'll get a black hole with an event horizon.  To not have the horizon would violate the equations.
 
So with the Alcubierre drive, we could similarly say that the equations demand that this particular mass-energy distribution must create this space-time geometry with horizons around it.  But we must also remember that the Alcubierre solution was found by solving the equations backward.  It started with the space-time geometry that has this FTL behavior, and then worked backward to find the mass-energy distribution that causes it.  But it does not tell us how that distribution could actually be created, or how that Alcubierre space-time could be generated out of an initially typical space-time.  

We know the mass-energy that yields this solution is exotic and violates some energy conditions in physics (so it probably can't exist).  It is also likely that even if it can exist, it may be impossible to actually get it into the required configuration.  A common argument (though I have yet to see it demonstrated rigorously) is that, similarly to trying to build a wormhole, Hawking radiation would amplify as you approach the conditions necessary for the horizons and FTL behavior, and the thing destroys itself.  Which kind of brings us full circle -- your initial suspicion that there is a problem with having the ship generate this field around itself from scratch is probably correct, but for less obvious reasons.

Wat when do you think we'll be able to create our own artificial micro or mini blackholes- not just for interstellar drives, but also to examine so we can resolve some of these issues and outstanding questions? :)
 
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31 Aug 2017 15:16

A-L-E-X wrote:
Source of the post Wat are you also seeing issues with the "e" patch with regards to textures? I miss my clouds and I miss my rippling waves

Sorry A-L-E-X, I actually haven't updated in a while so I don't have an answer to that.  Surely someone else will though.

A-L-E-X wrote:
Source of the post Wat when do you think we'll be able to create our own artificial micro or mini blackholes

Hopefully not in my lifetime... microblack holes are stupidly powerful things.
 
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31 Aug 2017 15:30

Watsisname wrote:
A-L-E-X wrote:
Source of the post Wat are you also seeing issues with the "e" patch with regards to textures? I miss my clouds and I miss my rippling waves

Sorry A-L-E-X, I actually haven't updated in a while so I don't have an answer to that.  Surely someone else will though.

A-L-E-X wrote:
Source of the post Wat when do you think we'll be able to create our own artificial micro or mini blackholes

Hopefully not in my lifetime... microblack holes are stupidly powerful things.

Probably lol, but I think they may give us what we need in terms of interstellar propulsion- hopefully we'll be smart enough by then to know how to control them.  There was one movie I saw when I was up late (which is typically when these kinds of movies are on :P) that showed a new form of energy developed that came from a particle collider.  Basically the corporation that developed it held the rest of the world hostage and there was a group of people that didn't take kindly to it and sabotaged it.  Someone was trying to stop them and expose the corporation at the same time but just barely failed and the last scene of the movie was the planet breaking up into little pieces and scattering throughout the solar system......
 
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31 Aug 2017 15:36

Wat thanks for linking me to this!  What's the furthest we have done quantum tunneling to and what was the largest object that's been tunneled?  I read that it was 50 miles and the size of a bacteria but I'm not sure if that's still the record.
 
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31 Aug 2017 15:41

Gnargenox wrote:
Thank you, I love your cleaned up formula! I can even see where the 16 comes from lol. I assume U means constant velocity, or acceleration independent of time? When you say things like 10^10^52, I only think of fertilization rates for lawn care lol. Luckily I had this book by Cook laying around on the bookshelf. Sounds like the chances of quantum tunneling to Saturn are the same as picking a random atom in the entire universe and you picking the same one.
Green - 01.jpg
Anyway, I was zooming around the universe earlier today and wished I could find more Green Stars... I think I understand why I won't see any, even though our own sun is considered to emit mostly green wave lengths of visible light. Basically since all stars emit light in all wave lengths the color green is always drowned out by the other ends of the spectrum creating a "white" looking star. But then I wondered how could I see other objects that appear green to me without them also being washed out and appearing white? Since color is determined by temperature and brightness I guess the other objects in space that are green must be so dim that our eyes are not overwhelmed by all the other wavelengths of light. Here are a few snap shots of Green stars I have seen due to optical illusions, some nebula that are portrayed as green and some naturally appearing green objects in space.

Well some emission nebulae are green (and the filters I use to see them more clearly with make everything look green :P)  Typically these nebula are emitting narrow bandwidths of OIII (there are two of them- 496 and 502nm I believe.)
 
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31 Aug 2017 22:11

Watsisname wrote:
Source of the post Hawking radiation would amplify as you approach the conditions necessary for the horizons and FTL behavior, and the thing destroys itself.  Which kind of brings us full circle -- your initial suspicion that there is a problem with having the ship generate this field around itself from scratch is probably correct, but for less obvious reasons.

Yet, Hawking radiation doesn't stop black holes to form.

It also sounds like the initial Hawking radiation would be extreme, becoming a real problem for the crew.  But assuming that we can get into the proper configuration, I was more thinking how to sustain the property which allows FTL, which requires constant change of the spacetime geometry.  The deformation, as viewed from hyperspace, must move.  This problem may be identical to creating the deformation in the first place, though.  Finally, if we can assume that the bubble could both be created and sustain itself, how can the ship then shut it down?
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01 Sep 2017 00:01

Watsisname wrote:
A-L-E-X wrote:
Source of the post Wat are you also seeing issues with the "e" patch with regards to textures? I miss my clouds and I miss my rippling waves

Sorry A-L-E-X, I actually haven't updated in a while so I don't have an answer to that.  Surely someone else will though.

A-L-E-X wrote:
Source of the post Wat when do you think we'll be able to create our own artificial micro or mini blackholes

Hopefully not in my lifetime... microblack holes are stupidly powerful things.

When Part IV?  8-)
It was very interesting, it's amazing how a 2 trillion tons black hole is way more quiet than a 180 tons black hole (that would literally burn every for of life on the earth), it's also interesting to imagine how that explosion would look!
The universe is not required to be in perfect harmony with human ambition.

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01 Sep 2017 03:22

Salvo wrote:
Watsisname wrote:
A-L-E-X wrote:
Source of the post Wat are you also seeing issues with the "e" patch with regards to textures? I miss my clouds and I miss my rippling waves

Sorry A-L-E-X, I actually haven't updated in a while so I don't have an answer to that.  Surely someone else will though.

A-L-E-X wrote:
Source of the post Wat when do you think we'll be able to create our own artificial micro or mini blackholes

Hopefully not in my lifetime... microblack holes are stupidly powerful things.

When Part IV?  8-)
It was very interesting, it's amazing how a 2 trillion tons black hole is way more quiet than a 180 tons black hole (that would literally burn every for of life on the earth), it's also interesting to imagine how that explosion would look!

Great point!  That reminds me of something that I read that if we were inside a supermassive black hole at the center of the galaxy we would be fine (with proper breathing apparatus) even though we could not leave we wouldn't notice anything much different from being in regular outer space.  Maybe we would be sucked into another universe ;-)

I also read about a computer simulation of the collision of two supermassive black holes (galaxy mergers) resulting in the formation of an interior structure inside the resulting more massive black hole that resembles a special geometric shape called the Hopf Fibration.  This structure seems to come up quite often in cosmological theories of the origin of the universe, it looks like the union of two tori and has "strands" wrapped around which (to me) resemble what alternate timelines might look like (different outcomes in the same space-time.)
 
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01 Sep 2017 03:28

midtskogen wrote:
Watsisname wrote:
Source of the post Hawking radiation would amplify as you approach the conditions necessary for the horizons and FTL behavior, and the thing destroys itself.  Which kind of brings us full circle -- your initial suspicion that there is a problem with having the ship generate this field around itself from scratch is probably correct, but for less obvious reasons.

Yet, Hawking radiation doesn't stop black holes to form.

It also sounds like the initial Hawking radiation would be extreme, becoming a real problem for the crew.  But assuming that we can get into the proper configuration, I was more thinking how to sustain the property which allows FTL, which requires constant change of the spacetime geometry.  The deformation, as viewed from hyperspace, must move.  This problem may be identical to creating the deformation in the first place, though.  Finally, if we can assume that the bubble could both be created and sustain itself, how can the ship then shut it down?

Yes- how to shut it down and prevent it from creating its own bubble universe?
 
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01 Sep 2017 03:39

midtskogen wrote:
Source of the post Yet, Hawking radiation doesn't stop black holes to form.

Just so.  Hawking radiation isn't too important in astrophysical black holes because the actual space-time curvature (or tidal force) at the horizons is quite small.  However, as we have seen, it becomes very important for small (microscopic) black holes, where the curvature and tidal forces at the horizons are strong.  Similarly, with an Alcubierre drive, the curvature / tidal force near the edge of the warp bubble is extreme, and so too is the Hawking radiation.  By "extreme" we're talking temperatures comparable to the Big Bang.


midtskogen wrote:
Source of the post But assuming that we can get into the proper configuration, I was more thinking how to sustain the property which allows FTL, which requires constant change of the spacetime geometry.  The deformation, as viewed from hyperspace, must move.


I'm not sure how to view from hyperspace, but we can just view relative to the surrounding (flat) space.  The Alcubierre metric describes the location of a bubble which moves at arbitrary speed through the space, and the interior of which is close to flat, and allows a free-falling particle to move with it.

The FTL behavior of the bubble is thus built directly into the metric, and does not require that the geometry of the bubble itself change.  We can consider an "eternal" warp drive -- one which always was and always will be moving at the same FTL speed, and this would be a constant geometry for the bubble. Changing the metric may allow the bubble to trace out any arbitrary path through the space, and this is what Alcubierre first worked out as a generalized warp bubble in his paper.

I think what you're aiming toward though is that if the bubble is moving FTL, then how does the signal that causes those elements of space to change get there?  

There was an argument back in 1998 that the region in front of the bubble is not only space-like separated from the interior of the bubble (meaning signals from inside cannot possibly reach it, which I think is intuitive and means the ship cannot control the bubble after it is formed), but even more severely is also space-like separated from the whole surrounding space-time.  In other words, to create an FTL warp bubble, one must first distribute the mass-energy at FTL speeds.  This suggests that it is fundamentally impossible to make one.  Or to turn it off again, as in your last question.  This is one of the most common arguments for why the drive must be impossible, and it sounds reasonable.

However, a more recent (2002) study found that this argument is actually wrong.  It is possible to build an Alcubierre space-time which is causally connected in the regions that are relevant to the motion of the ship, and thus the ship can activate or deactivate the warp bubble from within.  Basically this works because even though the leading horizon is causally separated, the rest of the volume of the bubble is not, and signals can be sent there to change the space-time and reduce the strength of the bubble.  In other words you can't turn it off all at once, but you can do it in parts.


I did also find a paper which specifically investigates semiclassical corrections (adding in quantum mechanics) for a warp drive that is generated from an initially flat space-time (as opposed to the eternal warp drive).  Again they find the Hawking radiation to be thoroughly lethal, but an even more severe problem is that the space-time itself becomes violently unstable, specifically around the horizon in front of the ship which acts like the horizon of a white hole.  

In my view this is one of the more compelling reasons for thinking the drive is impossible.  A lot of people approach it from simple arguments of relativity, but the reality seems to be more subtle than that, and is what makes investigation of the physics of warp drives interesting to me.  I am quite sure the drive is impossible, but research into their properties promotes deeper understanding of gravitation and quantum mechanics.
 
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01 Sep 2017 04:27

Watsisname wrote:
midtskogen wrote:
Source of the post Yet, Hawking radiation doesn't stop black holes to form.

Just so.  Hawking radiation isn't too important in astrophysical black holes because the actual space-time curvature (or tidal force) at the horizons is quite small.  However, as we have seen, it becomes very important for small (microscopic) black holes, where the curvature and tidal forces at the horizons are strong.  Similarly, with an Alcubierre drive, the curvature / tidal force near the edge of the warp bubble is extreme, and so too is the Hawking radiation.  By "extreme" we're talking temperatures comparable to the Big Bang.


midtskogen wrote:
Source of the post But assuming that we can get into the proper configuration, I was more thinking how to sustain the property which allows FTL, which requires constant change of the spacetime geometry.  The deformation, as viewed from hyperspace, must move.


I'm not sure how to view from hyperspace, but we can just view relative to the surrounding (flat) space.  The Alcubierre metric describes the location of a bubble which moves at arbitrary speed through the space, and the interior of which is close to flat, and allows a free-falling particle to move with it.

The FTL behavior of the bubble is thus built directly into the metric, and does not require that the geometry of the bubble itself change.  We can consider an "eternal" warp drive -- one which always was and always will be moving at the same FTL speed, and this would be a constant geometry for the bubble. Changing the metric may allow the bubble to trace out any arbitrary path through the space, and this is what Alcubierre first worked out as a generalized warp bubble in his paper.

I think what you're aiming toward though is that if the bubble is moving FTL, then how does the signal that causes those elements of space to change get there?  

There was an argument back in 1998 that the region in front of the bubble is not only space-like separated from the interior of the bubble (meaning signals from inside cannot possibly reach it, which I think is intuitive and means the ship cannot control the bubble after it is formed), but even more severely is also space-like separated from the whole surrounding space-time.  In other words, to create an FTL warp bubble, one must first distribute the mass-energy at FTL speeds.  This suggests that it is fundamentally impossible to make one.  Or to turn it off again, as in your last question.  This is one of the most common arguments for why the drive must be impossible, and it sounds reasonable.

However, a more recent (2002) study found that this argument is actually wrong.  It is possible to build an Alcubierre space-time which is causally connected in the regions that are relevant to the motion of the ship, and thus the ship can activate or deactivate the warp bubble from within.  Basically this works because even though the leading horizon is causally separated, the rest of the volume of the bubble is not, and signals can be sent there to change the space-time and reduce the strength of the bubble.  In other words you can't turn it off all at once, but you can do it in parts.


I did also find a paper which specifically investigates semiclassical corrections (adding in quantum mechanics) for a warp drive that is generated from an initially flat space-time (as opposed to the eternal warp drive).  Again they find the Hawking radiation to be thoroughly lethal, but an even more severe problem is that the space-time itself becomes violently unstable, specifically around the horizon in front of the ship which acts like the horizon of a white hole.  

In my view this is one of the more compelling reasons for thinking the drive is impossible.  A lot of people approach it from simple arguments of relativity, but the reality seems to be more subtle than that, and is what makes investigation of the physics of warp drives interesting to me.  I am quite sure the drive is impossible, but research into their properties promotes deeper understanding of gravitation and quantum mechanics.

Wat, that sounds very "tachyonic"- where particles that move FTL will always move FTL and can never move slower than FTL- the speed of light is the lower boundary for them just like its the upper boundary for us.  Adding more energy actually causes tachyonic particles to move slower, not faster.  The speed of light then becomes an asymptote, not a limit (like absolute zero.)  Same as with absolute zero, when you jump beyond the asymptote, you enter a "bizarro" reality where adding energy actually has the opposite effect of what it does in our universe.  Using this model, which I did in some of my writings, actually necessitates the existence of a universe with a different arrow of time compared to ours.  The arrow of time would still be forward relative to what's in that universe, but would be backwards compared to us (as ours would be backwards compared to theirs- thus we would both seem tachyonic to the other, with the speed of light being the boundary between both- a luxon wall.)  One of the fascinating consequences of this behavior is that while our universe expands, theirs contracts (or appears to), and vice versa.
I actually wrote about this possibility five years before this paper came out.
https://supermanbatmanalexthegreatest.s ... y.com/2631
http://www.telegraph.co.uk/news/science ... wards.html
woah I am amazed at how much this matches what I had said….
The theoretical claims put forward in the Physical Review Lettersjournal could revolutionise the field of research into the origin and future of the universe.

In the paper titled ‘Identification of a Gravitational Arrow of Time’, an international team of world renowned scientists led by Oxfordshire-based Dr Julian Barbour challenge assumptions about the so called ‘arrow of time’.

The ‘arrow of time’ is the theory that time is symmetric and therefore time moves forward. They contend that there is no scientific reason that a mirror universe could not have been created where time moved in an distinct way from our own.

But in a quirk of science it is thought that if a parallel universe did exist where time moved backward, any sentient beings there would consider that time in our universe in fact moved backward

http://www.scientificamerican.com/artic ... ious-past/
Barbour and his colleagues argue that it is gravity, rather than thermodynamics, that draws the bowstring to let time’s arrow fly.
Looks like they also caught on to my idea that gravity and time are directly related since time is just as out of place with the other 3 dimensions as gravity is with the other 3 forces.
Also
http://www.dailymail.co.uk/sciencetech/ ... l#comments

What I said a few years ago:

https://supermanbatmanalexthegreatest.s ... y.com/2633

note the date and the part about arrows of time flowing opposite relative to each other but forward relative to themselves ;-)

Proof of Concept Origin
January 5, 2013
Basically, in my book I conjecture on a new theory of everything; in my theory each dimension can be analoged to a primary color….. in our universe each spatial dimension would be equivalent to an additive primary color (RGB) with time as the background (Black) with a complementary spacetime which consisted of dimensions that analoged to the subtractive primary colors (CMY) with complementary time as the background (White) as one space expanded the other contracts and vice versa (because the arrow of time flows opposite to each other but forward within each), It’s been peer reviewed and it seems there’s some excitement over this as this would solve the dark matter / dark energy problem by unifying the strong nuclear force and gravity (the strong nuclear force is carried by gluons and color charge and analoging dimensions to primary colors is gravity’s version of color charge) so now we have a strong force-gravity unification and an electroweak unification and we just need to combine those dualities. There are four layers to the omniverse, with universes of different dimensions in each layer (the number of dimensions in each layer bear a pythagorean relationship to the other layers and each universe has a parent superverse from whose parent black hole it was created. If you loop through the entire hierarchy of universes you end up back where you started, so the omniverse is not only cyclical time, but also in space. I guess I’ll leave that for a sequel lol.

BTW if there are multiple timelines they would be created right after the big bang, by the force of inflation and be emergent diverging timelines along two dimensions of time (think cartesian coordinates) and if the cyclic model is correct and dark flow does reverse the expansion of space, the time lines would converge once again with a Big Bounce as the universe deflated (rinse and repeat.) The antiverse would have opposing cycles (because the arrow of time was opposite compared to ours) and if there was someway to construct some sort of device (a la star gate) to tap into the barrier which separates the two (consisting of light, which does not experience the passage of time) than both time and long distance space travel would become possible through the second temporal dimension (which keeps each timeline intact)…… according to Einstein the past, present and future all coexist and it is we who move through them, so theoretically this should be possible. He also stated that the universe (or omniverse on a larger scale) created us in order to understand itself better, forming the framework for a cosmic collective mind which encompasses not only humans, but animals, plants, alien life, even whole planets (Gaia Theory, which has been proven multiple times) and even stars and galaxies, the only difference is the density of the level of consciousness, although planets (for example) are much larger than any single life form, their density of consciousness is much less, with their “memories” (fossil record) spread out over a much larger area, so any one spot (on our scale) is seemingly lifeless. But it’s not. The planet consists of a complicated series of checks and balances and delicate interplay between different parts that can and should be considered alive.
 
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01 Sep 2017 04:34

Watsisname wrote:
midtskogen wrote:
Source of the post Yet, Hawking radiation doesn't stop black holes to form.

Just so.  Hawking radiation isn't too important in astrophysical black holes because the actual space-time curvature (or tidal force) at the horizons is quite small.  However, as we have seen, it becomes very important for small (microscopic) black holes, where the curvature and tidal forces at the horizons are strong.  Similarly, with an Alcubierre drive, the curvature / tidal force near the edge of the warp bubble is extreme, and so too is the Hawking radiation.  By "extreme" we're talking temperatures comparable to the Big Bang.


midtskogen wrote:
Source of the post But assuming that we can get into the proper configuration, I was more thinking how to sustain the property which allows FTL, which requires constant change of the spacetime geometry.  The deformation, as viewed from hyperspace, must move.


I'm not sure how to view from hyperspace, but we can just view relative to the surrounding (flat) space.  The Alcubierre metric describes the location of a bubble which moves at arbitrary speed through the space, and the interior of which is close to flat, and allows a free-falling particle to move with it.

The FTL behavior of the bubble is thus built directly into the metric, and does not require that the geometry of the bubble itself change.  We can consider an "eternal" warp drive -- one which always was and always will be moving at the same FTL speed, and this would be a constant geometry for the bubble. Changing the metric may allow the bubble to trace out any arbitrary path through the space, and this is what Alcubierre first worked out as a generalized warp bubble in his paper.

I think what you're aiming toward though is that if the bubble is moving FTL, then how does the signal that causes those elements of space to change get there?  

There was an argument back in 1998 that the region in front of the bubble is not only space-like separated from the interior of the bubble (meaning signals from inside cannot possibly reach it, which I think is intuitive and means the ship cannot control the bubble after it is formed), but even more severely is also space-like separated from the whole surrounding space-time.  In other words, to create an FTL warp bubble, one must first distribute the mass-energy at FTL speeds.  This suggests that it is fundamentally impossible to make one.  Or to turn it off again, as in your last question.  This is one of the most common arguments for why the drive must be impossible, and it sounds reasonable.

However, a more recent (2002) study found that this argument is actually wrong.  It is possible to build an Alcubierre space-time which is causally connected in the regions that are relevant to the motion of the ship, and thus the ship can activate or deactivate the warp bubble from within.  Basically this works because even though the leading horizon is causally separated, the rest of the volume of the bubble is not, and signals can be sent there to change the space-time and reduce the strength of the bubble.  In other words you can't turn it off all at once, but you can do it in parts.


I did also find a paper which specifically investigates semiclassical corrections (adding in quantum mechanics) for a warp drive that is generated from an initially flat space-time (as opposed to the eternal warp drive).  Again they find the Hawking radiation to be thoroughly lethal, but an even more severe problem is that the space-time itself becomes violently unstable, specifically around the horizon in front of the ship which acts like the horizon of a white hole.  

In my view this is one of the more compelling reasons for thinking the drive is impossible.  A lot of people approach it from simple arguments of relativity, but the reality seems to be more subtle than that, and is what makes investigation of the physics of warp drives interesting to me.  I am quite sure the drive is impossible, but research into their properties promotes deeper understanding of gravitation and quantum mechanics.

Wat would there be a way to create a bubble of stable space-time inside the violently unstable space-time thereby protecting us from it but still have the advantages of the warp drive?  So you'd have a bubble inside a bubble....... 
 
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01 Sep 2017 12:00

Watsisname wrote:
Source of the post Hawking radiation isn't too important in astrophysical black holes because the actual space-time curvature (or tidal force) at the horizons is quite small.

That leads to an interesting question: How large is the event horizon at the instant it forms in a black hole?
Watsisname wrote:
Source of the post I'm not sure how to view from hyperspace

If we look down on Flatland observing the flatlanders' Alcubierre drive at work, I would imagine Flatland to be changing in a non-constant way.
Watsisname wrote:
Source of the post In my view this is one of the more compelling reasons for thinking the drive is impossible.

To me the easiest way to shoot down FTL warp drives would be to point out the paradoxes that arise from FTL communication.
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