Ask any question you want about Physics

originally posted by: IAmTheRumble
a reply to: Arbitrageur

Well dang, I was hoping i had found a loophole!
That leads me into another question, if you don't mind. How exactly is the warp drive capable of going faster than light, if gravity can't propogate faster than light? Or am i musunderstanding something, since it's based off of the warping of space and time, which is done through gravity?

Thanks, once more!!!

a thing can travel at the speed of light and still appear to act instantly. inertia appears to push back instantly. gravity and inertia are manifestations of the same thing. wheeler and feynman sought to explain inertia and gravity with the idea of a radiative energy that travels at light speed but travels through time such that the effect of distant masses appear to arrive instantaneously without violating the constraints of relativity to light speed. Einstein tried to incorporate mach's principle into relativity but failed. no one has really succeeded at resolving the issues with gravity and inertia yet.

a reply to: Arbitrageur

Although in fairness the calculations were done using GR. And if GR is wrong than we don't know. Problem is other than math we don't have a way to truly test the speed of gravity.

originally posted by: IAmTheRumble
I don't suppose you've heard about the mathematician (I forgot his name), who claimed to have proved that gravity propagates instantly? He did this by measuring the affect of the suns gravity on Earth and "allegedly" discovered, the Earth is actually being pulled 8 minutes ahead of schedule, IE where the sun "actually" is and not where we "see" it to be. Therefor he claims gravity is instant.

What is your take on this?

Sorry if this has already been posted, there are so many darn posts to read through!

Thanks!

This is what's called frame dragging but I think your confused on what it meant. Basically I earth is being pulled around the sun. However relative position and actual position vary. For example the sun is moving when we look at it we see its location as of 8 min ago. Through in distortion of space time due to speed frame dragging where space time bends and we are even further off.

originally posted by: stormbringer1701
Going on a road trip to alpha centauri at 99.9999999999 percent the speed of light. how much food, water, air and fuel should i take assuming a one way trip? because gamma...

I change my mind and return home at the same speed. how much food, water, air and fuel do i consume? because gamma...

when i and the people of earth reunite; how are the differences between my frame and their frame resolved? do I have a cargo bay full of food, a tank full of water, excess fuel, excess air, and a couple of days of beard growth or is all the fuel and so on gone and i have eight+ years worth of beard growth?

Traveling at that speed the trip would seem almost instant. So food wise your good fuel consumption to reach that speed is a whole nother matter. The energy requirements to get that close to light speed you would be talking more than every source of power on the earth. Only way around that is as speed increases the mass of our ship would have to decrease.

What do you think about Nikola Teslas' theory that enough electricity could create a lift in an object and if possible would that object be able to carry a human. If you haven't noticed i do alot of research on different ways achieve flight

originally posted by: dragonridr

originally posted by: stormbringer1701
Going on a road trip to alpha centauri at 99.9999999999 percent the speed of light. how much food, water, air and fuel should i take assuming a one way trip? because gamma...

I change my mind and return home at the same speed. how much food, water, air and fuel do i consume? because gamma...

when i and the people of earth reunite; how are the differences between my frame and their frame resolved? do I have a cargo bay full of food, a tank full of water, excess fuel, excess air, and a couple of days of beard growth or is all the fuel and so on gone and i have eight+ years worth of beard growth?

Traveling at that speed the trip would seem almost instant. So food wise your good fuel consumption to reach that speed is a whole nother matter. The energy requirements to get that close to light speed you would be talking more than every source of power on the earth. Only way around that is as speed increases the mass of our ship would have to decrease.

the question is can i just pack a sandwich or do i need a cargo bay full of food and shaving cream?

and in my frame of reference the distance seems a lot shorter. so WRT fuel i should experience less fuel consumption than the classical view though inertial mass increase will occur form some point of view. a lot of the relativity whatsamagoobitz about increased need for fuel exponentially with speed seems to be a problem of interpreting what is valid in each reference frame. that's why i am confused about the consumables. and consumables has bearing on the design of any interstellar ship.

a reply to: dragonridr

I have a piggy back question if you dont mind. What if a craft was made that was only big enough for 1 man and a few supplies. The rest of the ship would be the engine and things. Would it then be light enough to achieve light speed ( with the thought that we have the required energy)

a reply to: Arbitrageur

I've been thinking about that article you linked, since you have answered my first question. I am having a problem understanding how they measured the speed of gravity, due to Jupiter's gravitational pull on the light behind it. I'm going to go ahead and assume everyone agrees that gravity affects all other objects, no matter the distance. That would mean the light ray heading towards Jupiter was already affected by its gravity, but only slightly. As it begins to approach Jupiter to the point that we can see the ray being bent, what they are measuring should only be the intensity of the "gravitational field", not how fast gravity is propagating.

I feel that this could offer some helpful insight if i'm not mistaken. What do you think?

a reply to: rebellion7

Interesting you mentioned that, just recently I made a "lifter" to try and test it for myself. But I blew the transformer out... So I can't currently see if it works. But from what I've found, modern science links it to the "Ion Wind Effect". en.wikipedia.org...

If you're really interested I would suggest going to look at Thomas Townsend Brown, as he seems to be the one who did most of the pioneering tests and such.

originally posted by: rebellion7
a reply to: dragonridr

I have a piggy back question if you dont mind. What if a craft was made that was only big enough for 1 man and a few supplies. The rest of the ship would be the engine and things. Would it then be light enough to achieve light speed ( with the thought that we have the required energy)

it cannot attain light speed by the current understanding of physics because it has mass. but it is remotely possible that our understanding may be off. there are people who posit self consistent alternatives that cannot be tested on earth and have effects that would mask it from discovery via astronomical observations. the only criticism available is it is not the most simple explanation that accounts for gravity and inertia. (violates occam's razor) relativity is. and it is not testable in that what it predicts would not differ from observations that bolster relativity unless you were outside the solar system away from any large mass.

originally posted by: ImaFungi

If we take an electron into our pure nothing space. And wiggle it around. Will photons fling off from it?

I don't know what you mean by 'pure nothing space', but if you consider the space governed by the laws of physics of Standard Model which appears to have born in our Big Bang, the answer is "yes". If we had a universe with the fields & laws of physics that we know today, and the items in this universe consisted of an electron, and the photon field was in its ground state, and with some other mechanism 'wiggled the electron', then after this point in time the photon field would have a non-ground state and there would be some radiation.

Are you asking, can you imagine a universe without electromagnetism? Sure. You can invent various field theories and make some axioms about interactions. For instance, exclude the EM field altogether. And in those, moving electrons back and forth would do nothing in particular, other than emit very weak gravitational waves perhaps. But that's not our universe.

This is not a conceptual or philosophical issue. It is an empirical observational issue.

You see, what I am asking is; is electromagnetic field and propagation, entirely the exact substance of electron, or is there something besides exactly what is electron, that is needed, to allow electromagnetic field and propagation to exist.

We've already answered that question before. In the current understanding of physics, the EM field exists (as it has since the big bang) at all places at space as does the lepton field. Real electrons are like persistent 'bubbles' in the lepton field like real photons are 'bubbles' in the EM field. So they are separate entities. Consider that there are also quarks which also have charge and interact electromagnetically, these are quite different from leptons. So given the experimental facts that you can have EM radiation propagating without needing charges nearby, and quarks also interact electromagnetically, it makes most sense physically and mathematically to say that EM field is a separate entity from the charges, though they interact intimately.

Since it's an experimental fact that you can have permanently propagating electromagnetic waves without requiring any elementary charges & dipole sources such as electrons, then in principle the EM field has an independent existence. All current physical modeling treats the field as its own entity with elementary particles and their motion being the contributors to its changing.

This is the structure of Maxwellian electrodynamics.

In our universe, only particles with charge will interact with EM field, AND the EM field does not interact with itself.

One believes that if a different universe had started with lots of electromagnetic radiation and didn't have any fields of charges or dipoles, hen it would still be full of that radiation. It would also be extremely boring.

Standard Model: What is there: lepton fields + em field + other stuff. What they do: the interaction terms between the fields, such as the creation of EM waves from moving charges + other stuff.

originally posted by: IAmTheRumble
a reply to: Arbitrageur

Well dang, I was hoping i had found a loophole!
That leads me into another question, if you don't mind. How exactly is the warp drive capable of going faster than light, if gravity can't propogate faster than light? Or am i musunderstanding something, since it's based off of the warping of space and time, which is done through gravity?

Warp drive theory is very speculative and this sums up some key points about it in two paragraphs:

Emerging Possibilities for Space Propulsion Breakthroughs (NASA)

A theory about "warp drive": Using the formalism of general relativity, it has been shown that faster than light travel may be possible (ref 7). All you need to do is contract spacetime in front of your ship and expand spacetime behind your ship. This "warped" space and the region within it would propel itself "with an arbitrarily large speed" (ref 7). Observers outside this "warp" would see it move faster than the speed of light. Observers inside this "warp" would feel no acceleration as they zip along at warp speed.

So what's the catch? First, to expand spacetime behind the ship you'll need matter having a negative energy density like negative mass, and lots of it too. It is unknown in physics whether negative mass or negative energy densities can exist. Classical physics tends toward a "no," while quantum physics leans to a "maybe, yes." Second, you'll need equal amounts of positive energy density matter, positive mass, to contract spacetime in front of the ship. Third, you'll need a way to control this effect to turn it on and off at will. And lastly, there is the debate about whether this whole "warp" would indeed move faster than the speed of light.

The very last statement relates to your specific question as we aren't sure it would even work; it's unknown at this time. If you want to know more, this is an excellent hour-long presentation by the closest thing we have to a warp drive expert, Dr White at NASA, who admits the idea is speculative and he's not putting all his eggs in that basket but is also exploring other advanced propulsion methods:

originally posted by: stormbringer1701
the question is can i just pack a sandwich or do i need a cargo bay full of food and shaving cream?

You wouldn't even need a sandwich, you'd be dead. The radiation would kill you. But if you made a radiation-resistant android that consumed sandwiches at the same rate as you, a sandwich would be enough for the android.

and in my frame of reference the distance seems a lot shorter. so WRT fuel i should experience less fuel consumption than the classical view though inertial mass increase will occur form some point of view. a lot of the relativity whatsamagoobitz about increased need for fuel exponentially with speed seems to be a problem of interpreting what is valid in each reference frame. that's why i am confused about the consumables. and consumables has bearing on the design of any interstellar ship.

Feynman said your mass would increase but Einstein said no it wouldn't, we should call that momentum, not mass. Einstein said mass does not change with velocity, and I made a thread about this:

Science Quiz #2: Is E=mc² right or wrong?

I don't know why you're confused about the consumables as they are the same in each reference frame, but I'll take a guess. The way you phrased the question, you're traveling near the speed of light. If you neglect drag from the one or four hydrogen atoms per cubic meter, you don't require any consumables to continue traveling at that speed, because an object in motion remains in motion.

To understand the consumables you have to start from the launch pad, rather than assume you're already going the speed of light. They will work out the same in all reference frames, and when you do that, assuming any reasonable rate of acceleration, a sandwich isn't going to be enough. Neither is the entire mass of the universe, if you use current rocket technology.

Using our current rocket technology, there isn't enough mass in the universe to send a Hubble-telescope sized spacecraft to the nearest star 4.2 light years away within 900 years, so 4.2/900 is less than 1% which means you can't even get up to 1% of the speed of light even if the entire universe was your consumables, though the picture changes if you consider other propulsion technologies, but even the alternatives tell us what we really need to send a spacecraft to another star in a reasonable amount of time is a spacecraft which requires no propellant.

www.nasa.gov...


While technically the warp drive idea doesn't use "propellant" as such, we aren't sure exactly how much energy it would take to make the "warp fields", and while estimates vary they all end up saying quite a bit. So then the question becomes, what would we use as an energy source (if warp drive is even possible)?

a reply to: Arbitrageur

Well no actual zero rest mass doesn't increase at the speed of light but relative mass does. Your answer was a bit confusing.The relativistic momentum of a massive particle would increase with speed in such a way that at the speed of light an object would have infinite momentum. To accelerate an object of non-zero rest mass to c would require infinite time with any finite acceleration, or infinite acceleration for a finite amount of time.Either way, such acceleration requires infinite amount of energy.

Or using Einsteins equation you get a violation meaning mass can't exceed or even move at C. So Einstien made it clear mass doesn't magically increase but instead violates the rules in other frames of reference. And if this is possible GR is wrong. Now there may be ways around our universal speed limit but in any frame if reference we still can't move faster than C.

originally posted by: Arbitrageur

originally posted by: joelr
You really don't know that all of physics understands that in the quantum world there is no position and momentum and all sorts of other non-intuitive things that people have tried like crazy to disprove for the first 50 years but experiments continue to confirm it all to higher degrees of accuracy?

That's true. Quantum mechanics wasn't a pill easily swallowed. Karl Popper didn't believe in uncertainty either and in 1934 he proposed an experiment to prove it false but Einstein convinced him that his idea was flawed.

So Popper worked on a better experiment which he finally published in 1982. He died in 1994 but the first time I know of where his proposed experiment was performed was in 1999. It didn't disprove quantum mechanics though Popper apparently didn't really understand all the implications of the experimental setup.

So I don't fault Popper or ImaFungi for questioning whether scientific interpretation is correct, however, what Popper appreciated more than ImaFungi is that experiments are the way to demonstrate truth. My guess is everybody learning physics has that moment when they realize that the subatomic world is not like what we know, and it does take some getting used to. Allan Adams, while teaching the quantum mechanics course on MIT opencourseware talks about his personal shock at how experiments seem to defy logic, and eventually had to accept that the universe doesn't behave like a classical ball on a spring. He also fully expects his students to go through some kind of denial phase like he did, but for most physicists it's probably just a phase, and they finally accept experiment and get over it.

If someone can't prove their assertion through experiment, it has limited value, and I give Popper credit for realizing that, and trying to prove his assertion through suggesting an experiment, though he never really got past the denial phase. I'm not too hopeful ImaFungi will either but there's always a chance.

I don't know much about Popper but I'm not surprised that an experiment to disprove quantum mechanics set up by a philosopher turned out to be wrong.
I think most physicists ignore the philosophical implications and it's completely denied in academics.

originally posted by: ImaFungi

A body which changes direction is acceleration yes?

If an electron is moving about a nucleus (if it were not moving, there would be no 'probability of finding it in one location or another', all the while staying in a relative proximity to the nucleus, it must be changing directions and therefore accelerating yes?

No. The classical model is a starting point only. Classical ideas do not represent the quantum behavior at all.
It's just easier sometimes to use classical language.

Can you please just tell me a sentence or more, as to why the electron changing directions away from a nucleus results in EM radiation, but an electron changing directions in proximity to a nucleus does not result in EM radiation.

To move to a higher orbit the electron has to absorb some energy. To move back down it releases some energy.
It has to do with energy change. If an electron gained energy and moved up but did not use all the energy then that energy has to be accounted for. A photon release would do that.

I suppose this all depends on the reality of the underlying fundamental fields of reality, because yes perhaps the trick is that, the frame rate of all particles in a reference frame are moving through time and space together, therefore the motion of the electron about the nucleus is being dampened in real time by other movements of fields and local particles, which do not result in EM radiation propagation. Pretty much the concept of mini black holes, or maybe where the idea of 'atoms are mostly empty space' comes into play. There is a lot of collective twisting and turning constantly at all levels of space. If something like this is thought to be the reason as to why an electron which admittedly must not be stationary around a nucleus, but also does not emit any radiation, then perhaps I could agree. It would have to be that in true space all electrons in a magnet are traveling a straight path at constant velocity, and collectively all the particles in the vicinity, and maybe even up to the spin of earth and the movement of earth, and the movement of solar system, and the movement of galaxy, equal at collective reference frame, which all though lots of rotating and revolving, equal in a true similar reference frame, a straight line of constant velocity, which smoothly echos down all the way to a magnet, which represents in its electron alignment the closest to the straight line arrangement of particles, and so it exhibits this clarity of power, which well... after we get through this conundrum, we still have to comprehend how what the electrons are doing in magnet A in body of magnet A effect across absolutely empty pure nothing space, the electrons in magnet B in body of magnet B which also are doing the same thing to effect magnet A.

Again if you want an accurate picture you have to read up on the wave nature of the electron. It's not like a little ball spinning around another ball.

I am saying, loud and clear!: Reality is indeterminate TO YOU!!!!!! Reality IS NOT indeterminate to itself.

If you dont understand, I can say it again, and it will still and always be true.

The only way reality can be indeterminate to itself, is if it is fake, if it is a computer program which uses symbols and code to bypass the real laws of physics. You know, like how we can create video games and dreams which by pass the law of physics by symbolically representing the real reality.

Reality is not indeterminate to itself? Does that even make sense?

Even if it did why would it be true?
Right now the underlying reality seems to be probability. How can probability be determinate to itself? It wouldn't be probability if it was. It would be a paradox and cannot be true.

Ok you say there is an EM field and an electron field. Lets forget about the electrons and the electron field for a moment. Can you state in a sentence or so generally, how the EM field exists, what its existence is substantially composed of?

The field has energy and momenta but it is only measurable when there is enough energy to create a real particle.
Where there is no particle there are disturbances because the field cannot be exactly zero at any point.
Those would be virtual particles. Although it's nothing physical in the way we think of physical, it's far from nothing.

originally posted by: ImaFungi

A body which changes direction is acceleration yes?

If an electron is moving about a nucleus (if it were not moving, there would be no 'probability of finding it in one location or another', all the while staying in a relative proximity to the nucleus, it must be changing directions and therefore accelerating yes?

No. The classical model is a starting point only. Classical ideas do not represent the quantum behavior at all.
It's just easier sometimes to use classical language.

Can you please just tell me a sentence or more, as to why the electron changing directions away from a nucleus results in EM radiation, but an electron changing directions in proximity to a nucleus does not result in EM radiation.

To move to a higher orbit the electron has to absorb some energy. To move back down it releases some energy.
It has to do with energy change. If an electron gained energy and moved up but did not use all the energy then that energy has to be accounted for. A photon release would do that.

I suppose this all depends on the reality of the underlying fundamental fields of reality, because yes perhaps the trick is that, the frame rate of all particles in a reference frame are moving through time and space together, therefore the motion of the electron about the nucleus is being dampened in real time by other movements of fields and local particles, which do not result in EM radiation propagation. Pretty much the concept of mini black holes, or maybe where the idea of 'atoms are mostly empty space' comes into play. There is a lot of collective twisting and turning constantly at all levels of space. If something like this is thought to be the reason as to why an electron which admittedly must not be stationary around a nucleus, but also does not emit any radiation, then perhaps I could agree. It would have to be that in true space all electrons in a magnet are traveling a straight path at constant velocity, and collectively all the particles in the vicinity, and maybe even up to the spin of earth and the movement of earth, and the movement of solar system, and the movement of galaxy, equal at collective reference frame, which all though lots of rotating and revolving, equal in a true similar reference frame, a straight line of constant velocity, which smoothly echos down all the way to a magnet, which represents in its electron alignment the closest to the straight line arrangement of particles, and so it exhibits this clarity of power, which well... after we get through this conundrum, we still have to comprehend how what the electrons are doing in magnet A in body of magnet A effect across absolutely empty pure nothing space, the electrons in magnet B in body of magnet B which also are doing the same thing to effect magnet A.

Again if you want an accurate picture you have to read up on the wave nature of the electron. It's not like a little ball spinning around another ball.

I am saying, loud and clear!: Reality is indeterminate TO YOU!!!!!! Reality IS NOT indeterminate to itself.

If you dont understand, I can say it again, and it will still and always be true.

The only way reality can be indeterminate to itself, is if it is fake, if it is a computer program which uses symbols and code to bypass the real laws of physics. You know, like how we can create video games and dreams which by pass the law of physics by symbolically representing the real reality.

Reality is not indeterminate to itself? Does that even make sense?

Even if it did why would it be true?
Right now the underlying reality seems to be probability. How can probability be determinate to itself? It wouldn't be probability if it was. It would be a paradox and cannot be true.

Ok you say there is an EM field and an electron field. Lets forget about the electrons and the electron field for a moment. Can you state in a sentence or so generally, how the EM field exists, what its existence is substantially composed of?

The field has energy and momenta but it is only measurable when there is enough energy to create a real particle.
Where there is no particle there are disturbances because the field cannot be exactly zero at any point.
Those would be virtual particles. Although it's nothing physical in the way we think of physical, it's far from nothing.

So if you're asking about taking an electron to an area void of spacetime, the first problem is that the electron isn't separate from the field. If it could be pulled out of it's field it still wouldn't work because the cloud of virtual particles around each electron are needed for it's function. Would a "piece" of a quantum field work in a void? I have no idea if it would or if it's possible to think of the field like that in any way?

Almost 3,000 atoms entangled with a single photon
Could lead to powerful quantum computers and more-accurate atomic clocks
March 25, 2015

www.kurzweilai.net...

Wonder how long they have had this technology?
A clock frequency for computers and communications faster than the military Cesium standard.

originally posted by: Cauliflower
Wonder how long they have had this technology?

D-Wave's quantum computer has been out for a while now, but I'm not sure what, if anything, it can actually do and apparently not even the people who build them know that:

The revolutionary quantum computer

Quantum computing is so new and so weird that no one is entirely sure whether the D-Wave is a quantum computer or just a very quirky classical one. Not even the people who build it know exactly how it works and what it can do. That’s what Neven is trying to figure out, sitting in his lab, week in, week out, patiently learning to talk to the D-Wave. If he can figure out the puzzle—what this box can do that nothing else can, and how—then boom. “It’s what we call ‘quantum supremacy,’” he says. “Essentially, something that cannot be matched anymore by classical machines.” It would be, in short, a new computer age.

As far as I've been able to tell the big advantage lies in potentially solving very specific types of problems so there is potential for a niche market aimed at that, akin to the supercomputer market. But, there are many challenges and I'm not sure they will help us browse the web any faster so I don't see us getting quantum computers at home anytime soon.

originally posted by: dragonridr
a reply to: Arbitrageur

Well no actual zero rest mass doesn't increase at the speed of light but relative mass does.

As I said Feynman would agree with you, but Einstein said otherwise so take up your argument with Einstein. I linked to his exact words on the topic, do you disagree with what Einstein said? It seems that you do.

I don't know whether Feynman is right, or whether Einstein is right, but what I do know is that they can't both be right because they said different things.

It's a conceptual thing which can't be resolved by experiment since the math comes out the same no matter who is right, but Einstein seemed to have some pretty good insights into nature so I'm not too quick to dismiss his view in favor of Feynman's.

originally posted by: Arbitrageur


Emerging Possibilities for Space Propulsion Breakthroughs (NASA)

A theory about "warp drive": Using the formalism of general relativity, it has been shown that faster than light travel may be possible (ref 7). All you need to do is contract spacetime in front of your ship and expand spacetime behind your ship. This "warped" space and the region within it would propel itself "with an arbitrarily large speed" (ref 7). Observers outside this "warp" would see it move faster than the speed of light. Observers inside this "warp" would feel no acceleration as they zip along at warp speed.

So what's the catch? First, to expand spacetime behind the ship you'll need matter having a negative energy density like negative mass, and lots of it too. It is unknown in physics whether negative mass or negative energy densities can exist. Classical physics tends toward a "no," while quantum physics leans to a "maybe, yes." Second, you'll need equal amounts of positive energy density matter, positive mass, to contract spacetime in front of the ship. Third, you'll need a way to control this effect to turn it on and off at will. And lastly, there is the debate about whether this whole "warp" would indeed move faster than the speed of light.

The very last statement relates to your specific question as we aren't sure it would even work; it's unknown at this time. If you want to know more, this is an excellent hour-long presentation by the closest thing we have to a warp drive expert, Dr White at NASA, who admits the idea is speculative and he's not putting all his eggs in that basket but is also exploring other advanced propulsion methods:

While technically the warp drive idea doesn't use "propellant" as such, we aren't sure exactly how much energy it would take to make the "warp fields", and while estimates vary they all end up saying quite a bit. So then the question becomes, what would we use as an energy source (if warp drive is even possible)?

The statement to the effect that we don't know if negative mass or energy even exists is patent nonsense. the ultimate in psychological compartmentalization. we know it does exist. period.

Further more there is reason to believe there is a tremendous amount of it.

lets start really small.

The negative energy condition exists in the boundary conditions inside casimir cavities. The Casimir effect even has a well known macroscopic analog in ship ports. the ocean waves on the ocean facing side of a ship are large and energetic. the water between the ship and the dock is calm and less energetic. this tends to push the ship into the dock.

Squeezed light can be arranged such that a portion of the energy of the waveform is negative.

the index of refraction in some metamaterials is negative and that in fact requires negative energy to happen.

(googling "metamaterial negative energy" is a starship believer's wet dream! try it.)

i was going looking for sarfatti's work but i found an online copy of Dr Woodward's book. check out page 207. he's awesome!

books.google.com... 9T_rO0sM&hl=en&sa=X&ei=RMscVYnVFMONyASlyoKwCQ&ved=0CF4Q6AEwCA#v=onepage&q=negative%20energy%20in%20metamaterials&f=false

in a gravitational system with two bodies it takes energy to keep them the same distance apart and that means a negative energy condition exists. in fact a rather large one.

in the standard model, in QED the model of an electron requires a huge amount of negative energy. the bohr electrol model was a cloud of negatively (here i mean electrical negative not exotic negative) charged dust at or near the gravity boundary such that the self energy is negative (exotic negative) and infinite. even after renormalization was invented there is a huge amount of negative (exotic) energy inherent in the equation for the electron.

the equation works. our standard model is built on it. the negative energy must therefore exist.

the argument against it being real is the WEC (weak energy condition) and the NEC. but the WEC and NEC are routinely violated in quantum physics. and there are inarguable instances where negative energy and mass do exist.

I hear that there are two types of exotic matter. Is this true?
Sort of. Strictly speaking, there are precisely as many types of exotic matter as there are energy conditions. Because there are only two pointwise energy conditions that are still widely believed to apply to matter, their violations define the two types of exotic matter normally considered. There is exotic matter that violates the Null Energy Condition (NEC) and that that violates the Weak Energy Condition (WEC). The NEC requires that the sum of the density of matter with that of each of its principle pressures be non-negative. The WEC requires in addition that the matter density itself be non-negative. The WEC, then, despite its name, is stronger than the NEC. So all matter that violates the NEC also violates the WEC, though the reverse is not true.

Which energy conditions matter in wormhole physics?
The two non-obsolete energy conditions are called the “Weak Energy Condition” (WEC) and the “Null Energy Condition” (NEC). [Their averaged versions are also in use.] The NEC requires that the sum of the density of matter with each of its principle pressures be non-negative. The WEC requires in addition that the matter density itself be non-negative. These conditions might some day become obsolete, as both of them are known to be violated by quantum effects. The matter required to hold open a traversable wormhole must at least violate the WEC.

what is not known is can the negative bare mass of normal matter be exposed in a useful way to do all the neat stuff we want to do with it.

a reply to: stormbringer1701
This Dr. White's area of expertise, not mine, but if the NASA site needs updating, so does the wiki article:

Here's what the wiki says:
Negative mass

In theoretical physics, negative mass is a hypothetical concept of matter whose mass is of opposite sign to the mass of normal matter, e.g. −2 kg. Such matter would violate one or more energy conditions and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass. It is used in certain speculative theories, such as on the construction of wormholes. The closest known real representative of such exotic matter is a region of pseudo-negative pressure density produced by the Casimir effect.

That also mentions the Casimir effect, but alternative explanations have been proposed for that so it's not entirely clear what causes the Casimir effect:
The Casimir Effect and the Quantum Vacuum

In discussions of the cosmological constant, the Casimir effect is often invoked as decisive evidence that the zero point energies of quantum fields are "real''. On the contrary, Casimir effects can be formulated and Casimir forces can be computed without reference to zero point energies. They are relativistic, quantum forces between charges and currents.

Your reference to negative electron energy levels do not imply negative mass to me since the overall mass of the atom or molecule is still positive.

Dark energy is the example Dr White mentions, but we don't really know how that really works, and don't have any idea how to do something similar on a human scale or if that's even possible, but it's an interesting topic of research. Maybe you can give Dr. White some pointers to speed up his warp drive development? He's the expert on this subject.