Spyman

Hi Severian, I intended to make long reply, but I only ended up with a mess, so... Both ships is accelerating.

I will have to accept the fact that science don't have an explanation, (yet). And I am somewhat worried that mainstream seems to take an approach where global energy conservation is not needed. Maybe I will change attitude when I have more/better knowledge/understanding but for the moment I will stick to the conservation laws. I will visit John Baez site "Physics FAQ" when I have more time. http://math.ucr.edu/home/baez/physics/ OK, that is something I don't have any problem accepting, I learn more by being wrong than when correct, I will check out the Integrated Sachs Wolfe effect. Sorry if I made an unclear question. Is there an possibility that LQC, (Loop Quantum Cosmology), or some other quantum gravity theory may shoot down Smolin's theory CNS, (Cosmological Natural Selection) ? This is still speculative, but according to the theory of quantum gravity a singularity is not formed. Instead, space and time do not collapse to a point but rather into a (four-dimensional) tube which opens into an entirely new region of space and time. The singularity "bounces" back out into a big bang. This means it is entirely possible that our own universe was created when a black hole was formed in another universe. http://en.wikipedia.org/wiki/Cosmological_natural_selection The Big Bounce is an event derived from the oscillatory universe interpretation of the Big Bang where the first cosmological event was the result of the collapse of a previous universe. Also, if the universe is closed, this theory would predict that once this incarnation of the universe collapses it will spawn another universe in an event similar to the Big Bang after a universal singularity is reached. http://en.wikipedia.org/wiki/Big_Bounce They might be conflicting but could also support each other... "gravity being in equilbrium with compaction" is your own words from one of the LQC's threads, Smolin's model needs a lot of bounces, but what if LQC predicts that black holes don't bounce and only compacts towards equilbrium ? And the quantum gravity models will probably put some constraints on the "tube" which may also support or shoot it down. I guess what I am asking for is more or less a "speculation".

LOL ! Obviously I am so confused that I am not able to express my question... And thats my own fault, so I guess I have to rephrase it again. To start: If the zero-point field is a field in space and if space curves the field have to curve with it, so if the curving is relative to frames then it is also frame dependent. I think both solo and 5614 is correct so far... Let's put it this way: 2 identical spacecrafts are in a huge void so the difference in gravitational acceleration would be small enough to be neglected. One ship is accelerating at twice the rate as the other. In both ships the Casimir force is measured in identically experiments but the setup for the experiments are done in their own respective frames. Will the crews in their own frames measure an identical strength of the force ?

Hi Martin and thanks for your thorough explanation. What you are saying is that in Smolin's scenario there is unlimited energy and all sub-universes could be infinite in mass and size ? I happened to stumble over this, before my reply to bascule: A more current view of white holes takes into consideration a revision to the standard model of the big bang theory which states that the big bang is an explosion that happens within a black hole, with the expansion that follows the traditional interpretation of the big bang, expanding into infinite space inside the black hole. Or in other words, a miniature universe is created at the core of the black hole, which expands into extra dimensions outside of this universe. The expansion taking place in this new miniature universe, if it could be perceived from an observer from this universe, could be looked at as a white hole. Matter that could not escape the intense gravitational pull of the black hole in this universe is instead sent speeding into the newly expanding baby universe. Using that logic, one could assume that our universe itself is a white hole. Hypothetically, this model could be used to explain the increasing rate of expansion of this universe: as matter from our parent universe is engulfed by our parent black hole (the black hole that created our universe), our own universe is fed this matter which could possibly have something to do with dark matter and dark energy, which currently is thought to contribute to the increase in the rate of our universe's expansion. http://en.wikipedia.org/wiki/White_hole So I wrongly assumed they talked about Smolin's Fecund universes, but I suppose it's one of many spinn-off's from his idea ? And I think that answeres bascule's question to, then there is no need for such a hertigage either. --------------------------------- Personally I don't like this "Free Lunch" idea so I would like you to clarify a few things a little more... 1. You claim that "energy conservation is being violated by expansion and constant dark energy density", but later on you reply to Kygron that there is an "IMPERFECTION IN OUR CURRENT KNOWLEDGE". How certain are we that there is a violation and not a misunderstanding or lack of knowledge ? 2. You also claim that the energy lost from the CMB due to expansion "did not GO anywhere", but in another thread I was told that in GR "light has to do work to climb up from a gravity well". Could it not be viewed as the light sent out inside a past and more dense universe and arrives now, infact have climbed up from a gravity well ? --------------------------------- I your last post you mention the ability to "shoot down" Smolin's theory and I wonder how it will fit togheter with the big bounce theory you mention in other threads. Words like "the idea of gravity being in equilibrium with compaction" inside black holes seems to contradict the possibility of sub-universes inside them. Can the theories coexist or will one of them have to go ?

I think you should include an explanation for you question... Every time you make a new one. (And there is a subforum for homework help.)

That would not classify as artificial gravity, because it would be real gravity. Disadvantage: Heavier ship = Greatly increased fuel consumption. Alternately the acceleration/decceleration could be used while travelling and upon arrival a quick search for a suitable asteroid, rendevouz and attache it beneath the ship. When it's time to go, just leave it behind. Disadvantage: IF you find an asteroid, it probably needs to be moved to a different position and speed. = Increased fuel consumption. (Depending on mission.)

How does the air inside know in which direction down is, where it needs to push the man ?

OK, then I will try to explain the 'need' while insane_alien tries to explain gravity. Lets make a thought experiment: Take a large pressure camber, like a big room and shaped like a dice with a hook outside on the top. One man enters and when the pressure is equal inside and outside, he seals the hatch. Will the man still be able to stand normal inside and will he notice any difference ?

No reply this time either... Hit and Run Tactics or what ???

Sorry for interrupting the discussion, but I want to sneak in a short question to Farsight... How many dimensions, in your opinion, are contained inside, (or a property of), the Universe ?

I accept your apologies, no hard feelings, after all it was a funny mistake. If I have interpreted you correctly then you belive that the air pressure is holding us to Earth and air is sealed inside a exotic container around the Earth. And you need to understand why this is wrong. Is that correct so far ?

Actually I meant puncture but English is not my first language. LOL - And now you have offended mine... The strong have the opportunity to protect the weak. The rich have the opportunity to help the poor. The knowledgeable have the opportunity to inform the ignorant. The ignorant have the opportunity to mock around. So do you really want to learn or just mock around ? With those kind of teachers it's no wonder about that... Which color do you want to have ?

Hopefully you don't get nightmares from the thought that NASA might accidentally punctuate our balloon...

Are you irritated about other peoples belifs or at the definition of the word "universe" ?

Okay, 116 reads and only one 'speculation' excluding me... ...and I would like an explanation so I'm going to bump this thread. -> B U M P ! Is the Unruh effect frame dependent or an absolute effect of the zero-point field ?

Your own thought or Stochastic ElectroDynamics (SED) ? SED has been developed by a number of physicists; their contributions can generally be characterized as speculative proposals within mainstream physics. More controversially, Haisch and Rueda have tried to use SED to provide explanations for the phenomena of inertia and gravitation. According to Haisch and Rueda, inertia arises as an electromagnetic drag force on accelerating particles, produced by interaction with the zero-point field. In their 1998 Ann. Phys. paper (see citations), they speak of a "Rindler flux", presumably meaning the Unruh effect, and claim to have computed a nonzero "z.p.f. momentum". This computation rests upon their claim to compute a nonzero "z.p.f. Poynting vector", but according to Bill Unruh this computation is incorrect. http://en.wikipedia.org/wiki/Stochastic_electrodynamics

You say you understand atmospheric pressure, so can you explain why the atmosphere don't expand out in space, there is no container preventing that and the vacuum in space has a very low pressure ?

I don't think Martin favored any model, (thats why I asked him), he only pointed out that they are different and I had mixed them. The Raisin bread model is not supposed to have an edge or center - it's a problem within the analogy. Objects with a redshift factor above about 2 is receding from us faster than light, highest confirmed galaxy redshift being z = 7.0 and the CMBR has a z about 1100. I don't know how to make the calculations but the points from where the CMBR was emitted is moving away from us several times faster than c due to the expansion of space in between them and us.

You are correct Martin, shame on me. I only had some faint memory of the Raisin bread model and thought it was a variant of the Ant on a Balloon model... Which model is favored for describing the rate of expansion with respect to current observations ? (Does more distant stars recede with the same factor as closer, (X * distance), or more/less ?)

Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American quantum chemist and biochemist. (He called himself, as well, a crystallographer, molecular biologist, and medical researcher.) He is widely regarded as the premier chemist of the twentieth century. http://en.wikipedia.org/wiki/Linus_Pauling

In BB theory the Universe emerged from a tremendously dense and hot state where the photons was forced to interact with the plasma, until space expanded causing the plasma to cool, so eventually the photons began to travel freely through space. Those photons where emitted in all directions, from uniformly everywhere inside Universe and they are the relic radiation we call CMBR. (Cosmic Microwave Background Radiation) The raisins are on the surface of the bread dough, I guess one could say that in this analogy space is the surface, so the center of mass should be somewhere in the middle of the dough, which would be outside of our 3D-space dimensions. I once speculated in another thread that time could be this 4th dimension but mainstream says: "center could only be reached by traveling in a 4th spatial dimension, not the time dimension of 4D spacetime, but there is no evidence that this 4th spatial dimension exists" and I still don't know the explanation for ruling out the time-dimension.

Dark Matter is clumps of matter that we can't visually observe, but from their gravitational effect on bodies we can see, (like stars), we know it's something there. Dark Energy is the force causing the Universe to expand. We don't know what it is or how it works, but we can observe that very distant stars are receding from us. Dark could be said to have two meanings: it's dark because we can't see it and it's dark because it's consistence is unknown. Just because the two phenomena is called 'Dark" they don't need to have an equivalence relation. In astrophysics, dark matter is matter that does not emit or reflect enough electromagnetic radiation (such as light, X-rays and so on) to be detected directly, but whose presence may be inferred from its gravitational effects on visible matter. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than is directly observable, indicating that the remainder is dark. http://en.wikipedia.org/wiki/Dark_matter In physical cosmology, dark energy is a hypothetical form of energy that permeates all of space and has strong negative pressure.[1] According to the Theory of Relativity, the effect of such a negative pressure is qualitatively similar to a force acting in opposition to gravity at large scales. Invoking such an effect is currently the most popular method for explaining recent observations that the universe appears to be expanding at an accelerating rate, as well as accounting for a significant portion of the missing mass in the universe. http://en.wikipedia.org/wiki/Dark_energy Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space.

Point taken, net momentum of the exhaust gas will be in the direction of movement so by use of conservation law the vehicle must be moving in opposite direction. During the acceleration the vehicle contains more fuel, (more mass), than when deccelerating, and since the force from the thrust of the fuel tank also must equal the termination in the T-split, (conservation law), the difference in mass will cause the ship to deccelerate more than accelerate. You are correct, the final state of the vehicle will be a constant speed with respect to the inertial observer.

OK, I have not read the thread from the beginning so I might come in from a wrong angle here... During the quickly ramp up, the fuel tank will act as an internal thruster and accelerate the vehicle in opposite direction of the fuel flow. When the ramp up is completed the acceleration stops and the vehicle moves with constant speed. (As long as the fuel flow remains constant.) After the firing time and the ramp down starts the fuel flow in the pipe will deccelerate the vehicle by terminating in the T-connection. At the time of null firing and zero fuel flow the vehicle will have slowed down to the same initial speed as before the ramp up. The vehicle are now at rest in a new position with respect to the inertial observer.

Well, I asked you in another thread: In this view, a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes. So where does the energy for every sub-universe come from in this theory ? Will these baby universes contain less and less energy since the black holes will become smaller and smaller or is there an outside universal energy source ? What needs to be considered is: In the case of a heritage then such a line of evolution would be finite. There could be an infinite masteruniverse, with infinite numbers of subuniverses, but since every new universe will contain less energy, all lines will die out at some point when they contain to little energy to form a new 'baby'. In my opinion I think it's easier to use Occams razor and cut off the complexity with infinite subuniverses and dimensions -> It's more likely to have only one single serie of evolving universes. And before you or someone else points it out to me: With a single oscillating line of universes, it's also thought to end, in heat death from the build up of entropy, (the second law of thermodynamics). But so would the masteruniverse also and problably in the same timespan.