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Does this mean that traveling faster-than-light can be considered a form of time travel?
Yes, which is why sci fi scenarios in which ships whiz between star systems will never, ever, ever happen.
To be able to move those sorts of distances and arrive at a time comparable to the origins absolute time would require the “time travel” aspect of ftl, right?
Earlier quoted context omitted.
Also, any kind of instantaneous communication. Unless the theory of relativity is superseded by something quite radically different.
High school educated talking here. Does Quantum Entanglement have any promise for instantaneous communication (theoretically) ?
Earlier quoted context omitted.
Also, any kind of instantaneous communication. Unless the theory of relativity is superseded by something quite radically different.
High school educated talking here. Does Quantum Entanglement have any promise for instantaneous communication (theoretically) ?
class RawQuantum {
value = () => this._hidden ??= Math.random()
}
class EntangledQuantum extends RawQuantum {
valueA = () => this.value()
valueB = () => 1 - this.value()
}
const {valueA, valueB} = new EntangledQuantum()
Earlier quoted context omitted.
High school educated talking here. Does Quantum Entanglement have any promise for instantaneous communication (theoretically) ?
https://news.fnal.gov/2020/12/fermilab-and-partners-achieve-... .
Earlier quoted context omitted.
High school educated talking here. Does Quantum Entanglement have any promise for instantaneous communication (theoretically) ?
Nope, entangled pairs are basically the following in JS: class RawQuantum { value = () => this._hidden ??= Math.random() } class EntangledQuantum extends RawQuantum { valueA = () => this.value() valueB = () => 1 - this.value() } const {valueA, valueB} = new EntangledQuantum() You can give valueA to one procedure and valueB to another and know that whenever the _hidden field is observed, the two will have complementar…
So to solve physics, you don't just have to be smarter and more creative than Einstein, but than Einstein and Godel combined.
Earlier quoted context omitted.
High school educated talking here. Does Quantum Entanglement have any promise for instantaneous communication (theoretically) ?
Nope, entangled pairs are basically the following in JS: class RawQuantum { value = () => this._hidden ??= Math.random() } class EntangledQuantum extends RawQuantum { valueA = () => this.value() valueB = () => 1 - this.value() } const {valueA, valueB} = new EntangledQuantum() You can give valueA to one procedure and valueB to another and know that whenever the _hidden field is observed, the two will have complementar…
Earlier quoted context omitted.
Yes, which is why sci fi scenarios in which ships whiz between star systems will never, ever, ever happen.
In reality it’s debatable, but within the logic of the fiction universe it holds, yeah? To be able to move those sorts of distances and arrive at a time comparable to the origins absolute time would require the “time travel” aspect of ftl, right?
Yes, the point is that any way to send a signal between space like separated events A and B (in sr or gr) would also allow a return signal to be sent back from B to event C in the past of A. So any means of ftl signaling (wormhole, warp drive or whatever) is tantamount to building a time m achine. No amount of techno optimism or can-do cleverness will ever be sufficient to surmount this obstacle in real life.
Incidentally the Gödel metric runs into causality violation in a different way: closed timelike curves. No need for ftl , it’s even less realistic as Einstein is quoted pointing out in the article.
So to solve physics, you don't just have to be smarter and more creative than Einstein, but than Einstein and Godel combined.
The article mentions "few known exact solutions". There are actually quite a number. Most are from after 1950. Cambridge University Press has two good books: Exact Spacetimes in Einstein's General Relativity (Griffith & Podolsky) - good readable (if you speak GR) account of the more common solutions Exact Solutions of Einstein's Feild Equations (Stephani, Kramer, MacCallum, Hoenstelaers, Herlt) - encyclopedic, author…