Halc

QM shows that it isn't predictable, but until the fully deterministic interpretations are falsified, QM does not kill determinism. If you can go back even a short time, then that prior state must be fully determined by the state shortly prior to that, and so on... Hence if we can go back a little and retain determinism, then we can go back all the way to the beginning. Of course there's no evidence of this short term determinism. For one, it presumes a meaningful state of a system, which is a counterfactual, and few interpretations of QM support counterfactuals. Don't confuse determinism with predictability. One can have a nice classical fully determined universe (such a Newton might have envisioned) and it would still not be predictable. It's pretty easy to show that. That's a good example of an uncaused thing. Bohmian mechanics (which supports counterfactuals) would I think assign hidden variables to the neutron system and a thousand identically set up systems would all decay after the same duration. MWI (also deterministic) would say that it decays after every possible duration. Copenhagen simply says we cannot know. Most of the others say something on the order of it occurring at some random time, which in some cases is 'God rolling dice'. None of the modern deterministic interpretations were out there during Einstein's time, and he seemed like a determinist type to me, so that's too bad. There are people (at least one of whom is contributing to this topic) which seem to spin a deterministic universe in a bad light, like it is somehow a thing to be avoided if possible, especially for decision making. I don't understand this aversion. I cannot conceive how a better decision can be made through a non-deterministic mechanism than through a deterministic one. All of evolution has favored structures that generate consistent output from identical inputs, despite leveraging quantum process in doing so. This shows that determinism is a good thing, even if it doesn't exist in reality.

Light from that star was emitted about 8 billion years ago when the star was about 5.5 billion light years away, both time and proper distance per the cosmic (expanding) coordinate system. That star, if it currently exists (unlikely), is a burnt out husk right now and doesn't shine at all. More likely it blew up and doesn't exist at all, or is a black hole or some such. Yes, it could not have been traveling for longer than that, and it doesn't need to. Such distances use an expanding coordinate system where light speed isn't constant. But also, absolutely nothing we see in the sky now was emitted further away than about 6 billion light years away (proper distance). Sure, the galaxy/quasar/whatever may be 40 billion light years away now, but we're seeing it where it was long long ago, which was much closer. The CMB light is the oldest, and that light was emitted from less than one billion light years away. That light isn't from any 'star', but it is from the formation of the first hydrogen atoms. You're going to have to unlearn this common misconception if you want to actually understand cosmology. The big bang happened literally everywhere and was never a 'point', and there is no rushing of material from a point into 'empty space' so to speak. Getting your information from peer-reviewed sources is a far better choice. I can find a 'doc' that states just about any nonsense I wish. Your source apparently claims to have measured something outside the observable universe, something which is by definition a contradiction.

Alternate theories that posit absolute velocity and time and non-isotropy of light speed (such as LET) still do not predict any empirical differences. Yes, the clock rates on Earth would change over the course of the day and year, but none of those effects would 'show' (my bold). If it were, we'd have a method to empirically determine the preferred frame and one of SR or LET would be falsified. So asking for 'evidence of this' is unreasonable. Lidal is claiming the possibility of 'evidence of this' by incorrectly calculating that the signals would reach the detector at different times in the moving lab frame. It is his calculations that are necessarily wrong, and not his assertion of absolutism, which is merely 'probably wrong' and not necessarily wrong.

If your proposal is one with absolute velocity, then it is a different proposal than SR. SR has relative velocity, not absolute. With SR, all calculations should be computed relative to the chosen frame, and you chose that of the lab in the ship. Under an absolute hypothesis, all calculations must be performed relative to the absolute frame, which has not been identified. How do you know the absolute velocity of anything? It's not like the water is stationary since water moves at very different velocities from place to place and from time to time.

OK, we're taking about the frame of the ship in all this. In that case, v = 0. Or v = the speed of the water going by outside, but water moving nearby has zero effect on how long it takes for light to get between a bunch of stationary emitters and detectors. Nothing is receding except the water, and the water isn't detecting any light.

There seems to be no actual theory behind your idea, so no quantifiable prediction. What problem does it solve? If it doesn't solve one, and it also contractions the last century of physics, and the only experiment you envision is one that is wildly unfeasible, then there's really no point in it all, is there? I mean, I could posit that pink elephants only on some planet 100 LY away can locomote around with reactionless thrust. Why haven't we tested that idea? Or we can posit that physics is the same everywhere except for humans, all without evidence. OK, that last one is real, but funny that it would be so easy to verify, and yet no attempt is made.

Well, it would match the 'usual methods' only if the clock at the 'afar' place was a similar gravitational potential relative to the clock measuring the trip around the ring. Would it now? That seems to violate your stipulation that the ring rotates at the same angular velocity as the material local to it. Maybe you imply that the Sagnac device would somehow not work correctly in this situation. Would the sum of the two signal times still be the same as the non-rotating case, which is basically πD/c ? Also, an interferometer measures femptosecond differences and would be pretty inappropriate for measuring the ~4 month difference in the signals going each way. How about we use a calendar instead? A superfluid wouldn't move with the spinning thingy, but a regular fluid would, and energy input would be needed to keep it spinning. OK, so you measure the rate at which the fluid rotates by somehow confining sound to a ring of the stuff. Clue: Ditch the plastic galaxy and instead spin a hula-hoop with fluid in it. You can put your sonic rotation sensor in there, and measure if the fluid rotates at the same rate as the hoop, slower, faster, backwards, or not at all. With light, relativity predicts numbers corresponding to no rotation of the 'medium' at all, regardless of where the ring is going or how fast it spins. You can speculate some different answer, but absent an actual experiment, what's the point except denialism? What does any of this have to do with the presence of dark matter or not. It's just more matter which is hard to see or feel directly. It isn't anything magical, and this experiment seems to be an attempt at a aether detector, not relevant in any way to the existence of dark matter or not.

Totally agree that 100% is unrealistic. They're not all going to make some arbitrary goal. Fire is a bad goal because they already have it at the start, so 100% in that case. The 'after 50000' part is not specified as a deadline. The original poster allowed different times. Less is bad as well. If they get to say space in 40000 years, odds are very high that they won't be technological after 50000. There are multiple deterministic interpretations of QM, so unless you're aware of them all being falsified, we know no such thing.

To quote his clarification: So it taking longer or not is irrelevant to what the OP is asking. The question is, what percentage gets there. There are of course several problems with the OP. The fact that humans need to be 'put on' each of those 1000 planets implies that the planets don't already have people on them, and if they don't already look exactly like our Earth 50000 years ago, what else is different? Is there something to eat? The unstated differences are likely to make survival impossible. So we all took the question as seemingly intended: 1000 identical copies, complete with all people at the time, solar system, etc. He asks just above: "would fire be created". Fire happens naturally, so of course. Controlled fire by humans has been around for nearly a million years, so again, of course. He gave s short list, and the implication was simply a technological outcome, enough to give us the capability of wiping ourselves out seems to be the only criteria that matters. Yes, I agree that the question wasn't posed with particular rigor. Another assumption is non-deterministic physics (or some other environmental difference on each of the 1000 worlds. If everything is identical and physics is deterministic, then not even chaos theory allows any differences at all between them. This implies the 1000 worlds are each isolated in their own identical observable universe. An assumption of non-determinism is again irrelevant since it's absence renders the OP question moot. I pointed out repeatedly that they would already have fire. I don't know what you mean by a planet having 'no history'. I mean, history is part of the state of a thing, so if the history is different, the copy isn't identical. Are the humans on these other places stripped of the knowledge and experience that the humans on actual Earth 50000 years ago had? I don't think the OP intended anything of that nature.

You're talking about flat spacetime that wraps in one dimension, sort of like Pacman game. Yes, One can do SR exercises in that, eliminating say acceleration necessity, but at the cost of having a preferred orientation of axes and also a preferred frame, a violation of the first premise. So you, at Earth, see a line of Earths in opposite directions but none of the others. You can travel to one of them and compare clocks when you get there. It's the same Earth after all. Or Earth can travel to you. You already have that with normal spacetime (infinite in all directions). The difference in age between the twins when they reunite is a physical fact, meaning it isn't in any way frame dependent. And in so doing, they have a test for being stationary in the preferred frame. You seem to realize this because yes, the one-way speed of light can now be measured. Given the wrapping geometry you describe, absolutely, yes. Sounds like a Sagnac effect which yes, can be used to detect rotation. Thus rotation is absolute. I cannot follow this. Yes, there is frame dragging, but it isn't going to be measured at such low gravitational gradients such as exist at the edge of a galaxy. You have a ring, implemented with say a number of mirrors to keep the refractive index at 1. What experimental result are you expecting here? Is the ring rotating with the galaxy? Is this just a huge-scale Sagnac rotation sensor? What at all does this have to do with your wrapping SR example. As soon as you introduced a galactic mass and dark matter and such, SR no longer applies.

He said "ie invented fire, internet, space flight, cars etcetc", and those things are pretty inevitable given the state 50000 years ago. It just doesn't take exactly 50000 years in each case. Maybe 20000 or 200000, but it gets there. You said Chaos theory says 'no' to the question in the OP, and it was that with which I was disagreeing. Agree about the annihilation bit, but the goals mentioned in the OP would already have been achieved in that case. We were never capable of destruction of the species before the advent of fire, flight, and cars. It could admittedly happen (and almost did) before the internet came around, so that one is far less inevitable. About the 'crucial person', that depends on what you mean by it. I mean, sure, one idiot can push the button and doom a world permanently back to near animals. There are several examples of crucial decisions that prevented things like that. But other things: No Einstein say. Somebody else would have stepped up, and in short order. The time was ripe for one or more world wars given the state of things around 1900. The first war was perhaps a political fluke, but the second seems almost mandatory given the advances in military technology at the time, making the transitions from [he who has the most soldiers] to [he who invents (and uses) stuff first] and finally to [endgame where either MAD dominates, or one power takes a permanent brutal hold] Of the 1000 worlds (from 50000 years ago, not 1900), how many manage to place a permanent self-sufficient off-planet colony somewhere? Not many. Not ours I bet.

Can't totally agree here. Sure, evolution would have gone in a completely different direction in each place, but humans were pretty much as they are now by 50000 years ago. Neanderthals were well integrated into the blood lines of the southern breeds. Most of the adaptations that have been made since then revolve around dealing with new diseases as they pop up, which probably would be wildly different from world to world. Chaos theory has strange attractors, and humans going technological is a reasonable inevitability from a state that recent. So maybe 25% of those 1000 worlds? It would of course take more or less than 50000 years to do it on each. The 25% is a POOMA estimate. Probably higher now that I think of it, since the only way to stop it would probably be something that wipes us out, unlikely in that short time. The intelligence needed is already there (and is actually currently on the decline), so it seems to be a matter of time. As for an illustration of chaos theory, consider 1000 copies of Earth circa 1900. None of the humans alive today would exist on any other world after 123 years. There's no attractor for that. War(s) is inevitable, but the actual main players are not. Of those 1000 worlds, technological civilization would end before 2023 in many (majority?) of them. We've come too close too many times to make it particularly probable that we get as far as we have. Humans had controlled fire for at least 3/4 million years. 50000 is nowhere far back enough to ask if it would happen again.

A for() loop is just a generalized form of a while loop. They're essentially the same thing. A do loop is different only in that it executes the body unconditionally at least once, which is inappropriate for summing up an array since it would generate erroneous results with an empty array. Examples of each, including the invalid do loop. Each assumes a line int sum = 0; at the top. for (int x = sizeof(numbers) / sizeof(int); x; x--) sum += number[x - 1]; for (int x = sizeof(numbers) / sizeof(int); x; sum += number[--x]) {} // alternate way to do it int x = sizeof(numbers) / sizeof(int); while (x--) sum += number[x]; int x = sizeof(numbers) / sizeof(int); do sum += number[--x]; while (x > 0); // wrong // An example of traversing the array forwards instead of backwards // This can be done for any of the loops above, but I find comparison with zero to be more optimized. for (int x = 0; x < sizeof(numbers) / sizeof(int); x++) sum += number[x]; Except for the inline definition of int x, this is pretty much C code, not leveraging C++ features Differences, besides the do loop being buggy, is that the for loop the way I coded it lets x drop out of scope after the loop exits. I find them all fairly equally readable since they're all essentially the same code.

Escape velocity of Earth from the surface is about 11.2 km/sec, and of that energy is needed to get to the moon, which is around 1/2 km/sec from escaping Earth itself. I wouldn't call that 'well under'. Similar reasoning shows why it is so much easier to escape the solar system from Earth's orbit than it is to drop an object into the sun, let alone actually go into low orbit around it, which is currently beyond our technological limits.

In the model where t 'runs' at all, no such wait is needed. That's the model with the universe being contained by time, just like you and I are. We have a start and a finish with time unaffected by our temporary presence. You mean we study things from our current event (a perspective, that in the large scale of things, is a point in space and time). Science regularly describes the universe outside this one perspective, so no, it isn't particularly mind bending to consider it as a whole, without a preferred moment or preferred location. As for time being T or t, there is not really a difference. It is what clocks measure, no matter the interpretation. There is not a 'relativistic time' that is different than that, at least not according to relativity theory. I suppose there is a difference between the two in some kind of absolutist theory (something in denial of Einstein's theory), but then T is really undetectable, not something that can be measured or demonstrated. So then T would be that which flows (instead of a dimension), and t would be what a local clock would measure, and a second of t would not correspond to any particular duration of T. I'm not sure if the absolutist theories reference T at all in a generalized theory. If they are that like us, then their stories would be similar. As for it being 'back in time', my comment referred to the relativity of simultaneity. The current time of any distant place is frame dependent, and thus whether this planet occurs prior to or after our civilization is a matter of convention. If the universe appear younger to this distant place, then by that convention, they are prior, and their point of view shows a younger universe and perhaps they are unaware of things like accelerating expansion which didn't really start happening until around when our solar system formed. OK, well that is a widely held view, but it counters relativity theory. The vast majority of people don't care about the implications of relativity theory. The opinion is not necessarily wrong. There are alternative theories that take this stance, even if it took about a century longer to generalize them into an actual theory of the cosmos instead of just a local theory. I never said it was a coordinate. I said it was a dimension in relativity theory, but only has a defined orientation if a coordinate system is specified. Relativity theory (GR, not so much SR) interprets the cosmos geometrically as 4 dimensional spacetime, with 1 temporal and three spatial dimensions.

This seems to rely on the assumption that the universe is contained by time, rather than it containing time, per relativity theory. If so, then yes, the universe is a thing that didn't exist before, and somehow came to be after a countdown reaches zero from a finite or infinitely distant prior moment. Relativity theory says time is just one of 4 dimensions of spacetime, part of the universe, rather than the universe being a temporary object contained by time. This seems to suggest that time itself was created at some moment, and that at prior times, time didn't exist. That seems pretty self contradictory. Depends on how close to Earth-like you want. A rocky planet in the habital zone? Plenty of those. One with an atmosphere we can breathe? No evidence of anything like that. As for if Earth was first among the nearby planets, that seems absurd. There are plenty of older star systems. As for Earth being prior to really distant Earth-like places, per relativity of simultaneity, which one came first is a matter of the convention you choose to compare ages. You talk about defects in time, but give no clue as to what you might mean by that. No. Space is up, a direction perpendicular to north. The analogy is apt. There is no north of the pole, nor is there 'down' beyond about 6500 km. These are examples of dimensions that are bounded by the coordinate system, exactly the way time is bounded at the big bang by a cosmic coordinate system. This seems to suggest some sort of cyclic model, but they've had great trouble finding one that matches empirical evidence

The event horizon is a null surface, and as such has a coordinate area, not volume. I'm not sure of the relationship between this area and its angular momentum, all else being equal. Yes, a rotating black hole (Kerr metric) contains a ring singularity. A charged black hole (Reissner-Nordsrom metric) cannot have its charge exceed its mass. So no additional charge can be added to one that is sufficiently close. The mass in unaffected by this, and the event horizon 'radius' is determined by the mass. If there is a black hole with charge equal to its mass, you get a naked singularity, which is a singular solution to the metric. So (just thinking out loud here, not an authority), if you have a super-positive charged black hole near this limit, a negatively charged particle would be more attracted to it than a neutral particle. Thus I would think there would be a second charged event horizon for the negatively charged thing that is further out than that of say a neutrino. Also, the EM potential would be so steep that it would probably rip apart (an EM 'tidal' effect) neutral things like a neutron, pulling it into charged components and accepting only the one.

I presume it's supposed to turn despite no net torque applied. That can't work. Sure, you have a force at application points pushing it counterclockwise, but the torque applied between the plate and same points of application balance that, pushing it clockwise. No motion will result. Rule 1: Perpetual motion machines violate physics. Can't be done.

Per the no-hair theorem, one can dump antimatter in a black hole with no different effect than dumping ordinary mass (or dark matter) into it. It increases the mass and effects the angular momentum and charge accordingly, but no gamma reaction except for any interaction with say the accretion disk. This acts as sort of a long-term equalizer since any black hole will eventually radiate away with Hawking radiation, which emits no more matter than antimatter.

Apologies for slow reply, but I've been logged off for several days. If the paper touches at only two points, that’s a one-shot teleport from one event to another. There is no gate held open, and thus the concept of the velocity and acceleration of the ‘gates’ does not apply since an event is a frame-independent fact. So I think you mean rolling the paper so it intersects at a line following the time axis, thus forming a worldline of your stargate. Yes, you don’t need to distort the paper to do that. If you can create such a thing where the two gates are simultaneous in Earth frame, then you’ve created a time machine. All you need is a second set of gates that with the two ends simultaneous with the frame of some receding object. Go through the Earth gate, come back through the other one, and now it’s 1921. Just pointing out that if you posit this sort of thing, then circular causality results. Didn’t need to accelerate either end of a gate to accomplish it. That was the metric spoken of I think. If I get you right, then conversation across our dining table with has one person on helium and the other on Xenon, each respectively from the perspective of the other. It would be like trying to talk with your twin on the fast ship. OK, no time machine there unless you build a 2nd gate with the properties described above. Why would the gate time be synced with one end (Earth) and not the other? Wormholes don’t seem to have a preferred end like that. I assume they’re relatively stationary then, else they could not be in sync. OK, they could, but only in a frame where the two endpoints have equal and opposite velocity. Ouch! That kind of blew my frame reference clutch. Let me see if I get it. The gate ends are in sync in Earth frame, both say noon, 3.464 light hours apart. The ship moves at .866c and gets there in 4 hours (4PM), but subjectively only 2 hours pass on the ship. If he leaves at ‘noon’ (synced with Earth clock at departure), then the destination clock moves from 3:00 to 4:00 during the two hour trip the clock makes moving to the ship, so yes, the Earth clock (noon) is 3 hours behind the destination clock that reads 3:00. When the destination clock passes him at 2PM, the Earth clock simultaneously reads 1PM. If someone enters the gate at noon, he’ll appear at the destination at noon (according to both local clock and his watch). Not sure how that can be construed as not entering until a long time passes. Ok, he not only steps through the gate, but does so at .866c. In that frame, he exits the gate at noon, and the receding Earth clock currently reads 9AM, which is 3 hours behind. So I read you so far. He’ll not enter that end of the gate until 6 hours from now when it’s noon over there. You are opening a portal between events that are separated in a space-like manner. Nothing violated by that (except locality) until you open a second one synced in a different frame. The main reason it isn’t a big problem yet is because you’re avoiding accelerating the ends, which is why I attempted to explore that part. I think SR has problems with wormholes in the first place. There’s just no such concept in Minkowskian spacetime. You have to jump to GR for that, and SR is suddenly inapplicable anywhere and thus cannot be violated. The acceleration of the rocket doesn’t have any affect on what time it is back on Earth. You make it sound like a causal relationship when in fact it is just a changed choice of coordinate system, which can be done without actually accelerating.

You seem to be envisioning something like a stargate, a portal connecting the non-parallel worldlines of say two different planets. If one thinks of it as such, there's no reason why it cannot look just like a window. One can eat at a table that is half here and half there, and you can talk to the other person light years away as if they were in your presence, and can pass the salt and such. The characteristics of such a setup depend on said unspecified metric. Imagine a clock at each end of the table. If the clocks stay in sync despite the relative motion of ends of the wormhole, then one end can be accelerated as in the twin scenario, starting and ending in near proximity. When the other end of the gate returns, the table is still there and both observers (neither of which have passed anything except the salt through the gate) will have aged the same, resulting in the wormhole/portal becoming a time portal instead of a spatial teleport setup. In other words, the portal can be changed from connecting events with space-like separation to connecting events with time-like separation. Similarly, the stargate could be set up at constant separation but vastly different gravitational potentials. If the clocks tick at the same rate, it quickly becomes a time machine. If the two clocks do not stay in sync, the two parties eating at the table will have difficulty communicating since one will be 'faster' than the other. The setup could be used to determine the absolute rest frame since the clock that objectively ticks faster must be moving slower. The principle of relativity would be violated.

A CPU cannot have no program loaded. There is always the instruction it is executing, and the one after that. A CPU consumes the most power from transistors changing states. It takes X amount of energy for a transistor to switch from on to off and back again, so you multiply that by the rate the switching takes place and you get an idea of the heat produced by the chip. Many systems (laptops, phones especially) have a low power mode where the software recognizes low demand for services and puts the device into low power mode somehow. This probably involves a significant reduction in the clock rate which directly affects the rate at which those transistors change states. At a lower clock rate, a lower voltage might be required to maintain this reduced performance, and low voltage also reduces the energy needed for the state changes. The CPU is a synchronous device, so everything on it is dependent on the clock. If the clock is stopped altogether, the CPU does nothing and comsumes only static power which is minimal. It also would be totally incapable of recognizing a sudden demand for its services, so something outside the CPU would need to be involved in the monitoring of demand. It would not be software controlled since no software can run on a stopped CPU. Not sure if any device actually stops the clock to a CPU on a device that isn't fully shut down.

Great. A cartoon eye. No, an electron microscope can only see things sitting still since it works effectively by touch, not light as implied by the eye. What they're probably detecting for electrons is some kind of charge detector like is used by a ground-fault detector in your bathroom outlet. Not sure if you can turn it on and off since it is a passive device. If the device takes no measurement (has no effect on the electron) 50% of the time, then 50% of the time the electron will reach the target with a simple pattern and the other times with an interference pattern. If the electrons are coming continuously, you'd see the pattern change from one to the other as the sensing device is function or not for whole seconds at a time. If they're using photons, I know a diagonal polarizing filter at the slits is enough to eliminate the interference pattern. You can't turn a polarizing filter on and off either, unless there is some really weird gadget that does this.

The 'device' can be the far wall on which the interference pattern appears, which isn't something that can be 'turned on and off' 50% of the time. Perhaps you have a specific device in mind that can meaningfully be turned on and off, and thus allowing a more specific answer. And yes, there being a human involved anywhere or not makes no difference. The vast majority of quantum measurements/collapses take place without any human being immediately aware of them. This is true even with experiments set up in labs by humans.

How about a galaxy 50 BLY that-away? Definitely mathematically expressible, but so is a perfect square. Neither is physically observable, at least not by us. It would be measurable ('observable' makes it sound like a life form is necessary) by something in that galaxy. Does that make a difference? A relativist would say it doesn't exist relative to Earth and v-v. Existence is a relation (not an objective property) in such a view, which is precisely the attraction of it. If you accept the principle of locality (no faster-than-light information transfer) in quantum physics, then it is a mistake to assert the specific distant galaxy exists at all. It leads to contradictions per Bell's theorem. That throws quite the wrench into the idea of objective existence. Side note: I agree that a route doesn't require my existence. My sister doesn't exist, and yet the route does. Of course, expressed as a relation, the route to the Milky Way doesn't exist to my sister, so go figure.