That makes more sense.   Yes, it is nice that the Alcubierre drive, being within the realm of general relativity, can be described mathematically.  The equations work both ways, so on one hand you can take a given distribution of matter and energy and predict how space-time behaves around it, or in this case you start with the behavior of space-time that you want and the equations tell you what sort of mass-energy would create it.  Of course solving the equations in that direction easily leads to unphysical situations or impossible mass-energy requirements, but if you take those as given then the math still lets you describe it, as in if you did have an Alcubierre drive, then what would it look like?  

For a "ZPE device", I think describing how it would work (in even the impossible sense) would be up to what kind of assumptions someone wants to use to model it.  Zero-point energy is a real thing, but there isn't a clear physical framework to describe how you would power something with it.

then what would it look like?

What do you mean by this? Are you wondering what the physical structure and schemata of the space craft will look like? Or what it might look like from the outside of the warp bubble if somebody was observing it?

I mostly mean the appearance of the bubble.  

The starting point for speculating on Alcubierre drives is to assume a particular geometry of the space-time.  The mathematics of general relativity then predicts the paths that light rays will take through that space-time, and therefore what the warp effect will look like, for all observers (inside or outside).

The structure or design of the spaceship on the other hand is not directly or uniquely determined by that math.  You could imagine all sorts of space ship designs.  The only requirement you'd need to meet from a logical point of view is that the ship be wholly contained within the bubble and not be destroyed by any tidal forces generated.  Beyond that, shape is mostly inconsequential, as is the material, or anything else.  General relativity doesn't care too much.  What is generating the geometry of the warp bubble is not the ship itself, but whatever magical distribution of space-time bending mass-energy that presumably is contained somewhere within the ship somehow.

I'll dig around online tomorrow to see if I can find any papers discussing the outward appearance of warped space/time. Seems like a fun way to spend a Monday  .

To venture a educated guess here and now I would say that the warp bubble may be invisible altogether to naked eye observations, but possess very blue or red-shifted energy signatures visible in other spectrum's. Also, at certain times you might see whatever gamma radiation looks like if you are right next to it... not that you would want to of course.

I say invisible because space/time is warped into a geodesic shape, bending light around it as it does so in something like a photon sphere (?) At best you might see a distortion?  I do not know if a lab ever made something even remotely like this, and recorded its outward appearance. 

The warp bubble is quite visible to those outside of it.  Light rays are highly deflected by it.

These are two visualizations made by the SXS Collaboration.  (This is the same group that makes the visualizations for the gravitational waves from events detected by LIGO, so they are credible).

[youtube]ugvsiT0b7pw[/youtube]

[youtube]hPrVjwDxQPY[/youtube]

These are two visualizations made by the SXS Collaboration.  (This is the same group that makes the visualizations for the gravitational waves from events detected by LIGO, so they are credible).

Nice. It looks like the new warp effects in SE 0990 are pretty accurate. I did not want to point out the SE effects because I thought it might be cheap researching on my part .

Anyway, I promised some papers, and here they are:

http://u2.lege.net/cetinbal/PDFdosya/AlcubierreWarpDriveSpacetime.pdf
Page 5-7 of the document actually outline the very thing we are discussing here, along with a proposed lab experiment. It ties in interestingly with Gaussian Sphere, which describe a space/time warp quite neatly.

Specifically:
"As the Alcubierre LIF (ALIF) warp sphere takes on a large spacetime expansion boost and starts to move off-braneas suggested by equation (7),the photons emitted from it will not be able to intersect the coordinate observer (lab) frame because the photons were emitted off-brane from the ALIF. This is the reverse scenario we discussed earlier where photons on the brane were not able to interact with an electron off of the brane. Unless something acts on the off-brane photons to reduce their boost, they will not be detected by the on-brane coordinate observer. Hence, an Earthbound coordinate observer will most likely see a dimming effect when viewing the ALIFas its spacetime expansion boost increases. Similarly, the ALIF willsee his/her surrounding universe grow dimmer and dimmer as photons emitted on-brane cannot reach the now off-brane ALIF. [emphasis mine]"


The experiment mentioned in the paper can be found here. A paper criticizing the experiment might also be of interest.


A paper discussing what a warp may look like from the inside of the geodesic sphere (I thought the conclusion on page 9 to be congruent):
https://arxiv.org/pdf/gr-qc/9907019.pdf

A pertinent paper exploring the dynamics of trapped photons in geodesic curvatures, such as those surrounding black-holes. This relates to what was outlined in the first paper I linked to:
https://arxiv.org/pdf/1512.09094.pdf

A similar paper on the spectrum shifts of the photons in a geodesic:
https://arxiv.org/pdf/1703.07921.pdf

This one essentially clarifies our ignorance of a lot of physics in relation to warp drives:
http://www.enthea.org/docs/Warp-Drive-S ... asimir.pdf

That's all I have for now. What do you think?

[youtube]NtQkz0aRDe8[/youtube]

It looks like the new warp effects in SE 0990 are pretty accurate. I did not want to point out the SE effects because I thought it might be cheap researching on my part

The edits I did to the shader for 0.9.9.0 are based off of renders like the one Watsisname linked.

Procederal generation of planetary system in Space Engine over time and what we might really expect to explore.

Early on in the search for extrasolar planets (as in, around the turn of the century), it was found that giant planets were being preferentially discovered around metal-rich stars. This is consistent with the core accretion model of planet formation, where increasing the metallicity of a protoplanetary disk speeds up the dust accumulation rate early on in the planet formation process (traditionally, the logarithmic fraction of iron in a star relative to the sun, [Fe/H], has been the traditional marker for metallicity. In these early days of extrasolar planet science where each new planet discovery was important in building up a statistically useful sample of planets, radial velocity surveys tended to focus on high-metallicity stars to maximize their discovery yields, leaving the planetary population around low-metallicity stars rather unexplored. This changed with the Kepler mission, which discovered thousands of planets around stars of diverse metallicities, including a huge number of a type of planetary system where there are several super-Earth to Neptune-sized planets in close orbits around the star. These so-called "compact multi-planet systems" are among the most common type of planetary system in the Galaxy, and according to a recent study by Brewer, et alia, appear to be more common around stars of very low metallicity. They also find that the occurrence rate compared to stellar metallicity for hot Jupiters and cold Jupiters is nearly indistinguishable.

The fact that the occurrence rate of compact multi-planet systems jumps up as the hot Jupiter occurrence rate tends to zero can be easily understood in the context of hot Jupiters migrating inward wiping out low-mass planets in their path. But something more most be occurring here, as the fraction of compact multi-planet systems is flat from -0.3 < [Fe/H] < 0.4, despite the rising incidence of gas giant planets. The authors of the study suggest silicon may play a role, with low-[Fe/H] systems of high Si/Fe ratios apparently preferring low-mass planet formation.

Compact multi-planet systems are more common around metal poor hosts

As the Universe ages and the average metallicity of new stars and their proto-planetary disks increases, after a time the only kinds of planetary systems that will be formed will be these systems that have fast gas giant formation and subsequent migration. These systems end up as either hot Jupiter systems or misaligned multi-planet Jovian systems, like Upsilon Andromedae.

Essentially, the formation rate of habitable planets in Space Engine should be declining over time (assuming a flat ΛCDM Big Bang model where the expansion of the Universe is accelerating, and the age of the Universe is 13.7 billion years), and subsequently distance. Someone tell Issac Aurthur humans might only ever have the local neighborhood to explore and play with.

Interesting stuff Gnargenox. I had wanted to post the exact same thing a while back, but ended up forgetting .  Addressing the exoplanetary discoveries, it sort of annoys me when people who know very little about exoplanets and their discovery methods say that our solar-system is soooo unique and special because no-one has detected a solar-system twin to ours. Nobody gets it that there ARE detection biases based off of equipment limitations, as you described here. The fact that it is tied into physical properties related to the star just makes that much more sense.

As for Isaac, I think he is pretty focused on the immediate future (err, in astronomical timelines) for humanity, along with the basic assumption that more people will actually be living in space habs (and megastructures like megaearths, ringworlds etc) more then planets. I always thought he describes habitable planets more as recreational places. And only if we terraformed them from the inhospitable climate that they always had. Whenever addressing humans actually living on Earth-like exoplanets, he usually presented what we COULD do, but might not. Instead the general gist was just to leave the exofauna and flora alone for the most part, maybe harvesting some critter's useful bits for genetic engineering later on ourselves or some superfood we're working on. As for the far future - there's always black-hole farming! 

Gnargenox wrote:
BTW, there are NO aliens out there.

From here. Care to elaborate? Do you mean ET generally? Or in the conspiracy-theorist sense (in which case I'd agree with you whole-heatedly).

Care to elaborate?

Have YOU, personally, ever found a 15lbs nugget of gold laying on the beach? There are as many grains of sand as there are stars, eventually you should find a gold nugget large enough to represent the presence of life. I mean you are right there at the base of the mountain full of veins of gold, the ocean is eroding the mountain exposing the geology below. Storms have scrubbed the mountain side and washed the beach just like a gold miner pans for gold. Surely there should be a house sized nugget poking out of the ground around here, don't stop looking! We have got to be hot on the trail by now! Strip-mine the public beaches, right now!

Life might indeed spontaneously sprout from mud, we are an example of that. We also look around us and see possibilities of exactly the right conditions to reproduce this phenomenon. But are we really being objective or subjective about this? What do we know we don't know? What method are we using to calculate the probability of things on which we have very little to start with? The key to this study, I present below, is using proper scientific method on calculating these uncertainties.

One huge statistical hurdle is "what is intelligence?"; chemicals that reproduce and carry information through re-assimilation of other elements or time may or may not be conscious from our point of view, but on a different time scale it might out think us in a game of chess, every time. We couldn't ever communicate with it though. We wouldn't consider it much more than a large scale analog AI. This "alien" intelligence might not be interested or even capably aware of the outside universe.

Other problems about intelligence, might be that it all is hiding, rather than we are the ones in a fish bowl being watched by our overlords. Our nugget of gold on the beach doesn't do that. It stays right there in the out in open, and in most cases in our example it would be dug up and hauled off long before we ever stumble across it. Our beaches are void of gold nuggets it seems, even if the conditions are ideal.

A new method of determining this probability came to the conclusion we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). New Model Predicts That We’re Probably the Only Advanced Civilization in the Observable Universe

The Fermi paradox (The Fermi Paradox Is Not Fermi's, and It Is Not a Paradox) is the conflict between an expectation of a high probability of intelligent life elsewhere in the universe and the apparently lifeless universe we in fact observe. The expectation that the universe should be teeming with intelligent life is linked to models like the Drake equation, which suggest that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should nonetheless yield a large number of potentially observable civilizations. We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference. When the model is recast to represent realistic distributions of uncertainty, we find a substantial {\em ex ante} probability of there being no other intelligent life in our observable universe, and thus that there should be little surprise when we fail to detect any signs of it. This result dissolves the Fermi paradox, and in doing so removes any need to invoke speculative mechanisms by which civilizations would inevitably fail to have observable effects upon the universe.

Dissolving the Fermi Paradox

Others reason that this is "garbage science" and no better than any other guess about extraterrestrial life. To me that sounds like they mean to say optimism should guide the scientific method. Meh.No, We Haven't Solved The Drake Equation, The Fermi Paradox, Or Whether Humans Are Alone

Food for believers: could Oumuamua be a solar sail?

Have YOU, personally, ever found a 15lbs nugget of gold laying on the beach?

Heh, I did find lots of gold dust around where I live - does that count? Would that be a metaphor for unicellular life hiding under Europa's ice?

Anyway, I didn't mean to sound rude with my question, I'm just curious to hear what people have to say about "The Paradox" (yes, pretty much a misnomer) and their reasons for believing it. My stance is at this point: it's too early in the game to make any definite claims about anything. We honestly don't know enough about exoplanets, or even our own solar-system, for that. Reckless optimism only hurts this area of study, just as much as defeatist cynicism masquerading as honest skepticism. The annoying thing about a lot of these ETI-absence papers and articles is that they just address the uncertainties of the mathematical model with our current understanding of the universe, which is far from complete and no doubt subject to real changes next year or even next day. None of them really consider the sheer infancy of our observations, the age of the entire universe (so far!) and it's entailed sheer vastness. This may come across as a weak counter-argument, but when entire theories are completely dashed for the sake of brand-new, but better ideas with a greater pool of evidence to pull from, it makes more sense. So with that, we must resort to that tried-and-true Sagan quote (which somehow I knew I could use on this forum at some point  ):

"Absence of evidence is not evidence of absence". 

Cliche but true until we have the Final Answer, even if that is an impossible dream. 

My dear friend, I apologize if my capital letters and personal reference insinuated you were being rude regarding this pretty cool question. The gold nugget analogy was just meant to stimulate ideas about the scope of factors involved in determining our social-cosmic bearings and I think the last article I posted says it nearly as well as you that we simply don't really know squat, and that it is too early in the game to quantify. I simply think a hobby devoted to finding ET signals and observations would be a pretty bleak unless you stuck to exo-atmosphere study and such, you MIGHT find some pea-green soup.

Knowing what we know, what can we rule out? Knowing what physics allows, what could we expect in the realm of normal things? Can we hear a light bulb 5 light years away? 50, 500, 5000, (5^(n!)!)? Knowing what we know, what could ET know about us? How far back in time do we want to search, because we don't see things as they are now. If intelligence tends to wipe itself out or hides how far away should we be looking based on the age of the universe and the window of time life usually last? Should we just set a telescope on a swivel and throw darts?
    
If someone could come up with a mod for SE showing a bubble of the window in which we might expect to find life in the present time, based on the Drake equation and how life is procedurally generated in the SE code, with each planet tagged in the smaller browser window to the right (F1??), it'd be really appreciated.