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Halc

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About Halc

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    Baryon

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    USA
  • College Major/Degree
    Computer Engr
  • Favorite Area of Science
    relativity

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  1. 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.
  2. 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 fram
  3. 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,
  4. 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
  5. 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 elect
  6. 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.
  7. 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
  8. I can actually think of epistemological cases. The Egyptians of old were known for stamping out all mention of certain prior Pharaohs from the records. These were rarely entirely successful, but when they were, they did very much make them 'cease to having ever existed', at least from an epistemological standpoint. They very much have an ontological existence in history, but nobody can remember them anymore. Your memory (of this and that) very much once existed, and cannot cease to have ever existed. It just doesn't exist now. Same with history or Earth and our respective fathers, which
  9. This is very much a philosophical topic which needs proper definitions to communicate clearly. If a brain is changed while being formed, it's still the same brain, just altered from some prior state. Putting a scratch in my car doesn't make it not-my-car. You change ever second of every day, and yet you're still you. A static unchanging thing cannot be alive. By definition, nothing can cease to ever exist. If it ever existed, then that’s that. It’s not something that can be ‘changed’. I can bring about a premature cessation to the duration of its existence, but that doesn’t make i
  10. Despite the wording above, I agree that dark energy isn't an actual force, but dark energy will begin to increase the proper separation between two relatively stationary objects, and that translates to a sort of kinetic energy which could hypothetically be harnessed to do work (imagine a seriously long thin string between them). Gravity will also separate the pair of objects when placed in the deep void * (regions of negative mass density relative to the mean), and gravity isn't an actual force either, at least not under relativity. Like gravity, I think dark energy can be expressed as a forc
  11. The question is, why do you think they do? 'Space' isn't something that can apply a friction-like force and begin accelerating an object. Assume we have two pebbles X and Y that are a megaparsec apart, and they're way out in the void between galaxies. Now a megaparsec is a long way. You can fit at least a couple dozen galaxies like ours side by side on one. Nearby galaxies are going to exert tidal forces on our pebbles drawing them apart, so we're going to ignore gravity and also dark energy and just concentrate on the expansion. Pebble X is stationary relative to the cosmological f
  12. Earth is not moving in some direction due to expansion. It is moving in some direction (relative to say the cosmological frame) because net forces on Earth or the materials from which it is composed have cumulated in its present velocity/momentum. Our velocity (relative to the frame of your choice) has changed by over 400 km/sec since the Spinosaurus was around, so those external forces are not insignificant. In other words, if I put two objects in space separated by say a megaparsec, that are stationary relative to each other and not subject to external forces like gravity from nearby o
  13. The author admits in the intro that an observer does not see the history of the universe. That question is discussed on stack exchange here which admittedly discusses the simplified case of a Schwarzschild black hole. This image from there: This clearly shows a finite history of some outside object (dotted worldline) seen by the blue worldline of our infalling observer, Cauchy horizon or not. Kino's Kruskal diagram shows the same sort of thing. The Cauchy horizon for a charged or rotating BH seems to have special treatment in that the spacetime beyond it isn't 'smooth', but I s
  14. I was going to jump on that. +1 for catching it. In my reply above your post, I mentioned the other companions all around you falling with you. They don't disappear from your sight. They're not 'below' you, they trace a worldline near your worldline and there is no way light from one nearby worldline doesn't reach the other, regardless of the direction in which this companion appears in relation to you. The usual local laws of SR very much do apply here per the equivalence principle. The falling observer is very much stationary in his own reference frame. That frame simply does
  15. That was the question in the OP, yes, and it has been answered. The feet that he sees are the feet from a few nanoseconds ago (falling frame), same as the feet you see now are not the present feet, but the feet in the past. Those feet were outside the EH when the light was emitted from them. I've said as much since my first reply in this thread. A body does not experience itself in the present since it takes time for any information to travel from say feet to head. So there's no anomaly in spacetime from the PoV of the falling guy. It's all normal physics to him, and he has no awarenes
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