Earlier quoted context omitted.
Shadows can move faster than light.
Shadows are an abstract concept (namely, the absence of light), not a physical thing.
I would argue that shadows are a very physical effect.
Travel through wormholes is possible, but slow
141–150 of 190 posts
Re: Travel through wormholes is possible, but slow
#142Earlier quoted context omitted.
Well, theoretically they could load their civilization up on a giant ship and move their civilization there over the course of a million years. Likelihood of success? Probably not great, but possible.
Everyone is missing the obvious solution. If we're talking about tech this fantastical, the best idea is to ditch our ephemeral biological bodies, jump onto a synthetic medium, and call it a day. Hit pause so the journey takes a fraction of a second, or spend 1000Y in a VR - do whatever you want. I don't see a future where we're this advanced yet still content with our frighteningly fragile bodies.
I mean at that point you don't have to choose - you do all those things, plus have some more of you spend a bunch of time figuring out the philosophical ramifications of bringing it all back together.
Add some check processes which periodically restore an old backup and have a conversation to see if the backup agrees to a merge as the moral monitoring system.
Re: Travel through wormholes is possible, but slow
#143Earlier quoted context omitted.
This depends on what do you mean by 'inaccessible'. Going there and back again, and telling your pals how things are 1000LY away is likely impossible. Expanding your civilization to more and more habitable celestial bodies, slowly but relatively surely, is entirely possible. This is how e.g. plants colonize vast spaces, being limited by the speed of their growth often by inches per lifetime. (You should also consider…
I get what you are saying, but it seems like the plant approach is mostly useless to humans. If the people on opposite sides of a galactic civilization are so far away that they cannot meaningfully interact, then it seems like that's no different than the other person not existing from their perspective.
Depends on the definition of useless or meaningful. If meaningfulness only extends to immediate political, social, economic or technological interactions then maybe an organic colonisation seems useless, I guess.
Unlike plants, through the power of electromagnetic communications and a culture based on shared knowledge, humans will know the others exist, even though that interaction will be slow with likely little-to-no-influence on their local evolution.
There would be huge cultural meaning even despite the lack of immediacy. Imagine living in a world where you know that there are other humans like you in space, living on other worlds light-years away. You might not be able to communicate immediately, but you know that they are there, and the universe is not so empty to you. You could look to the night sky and reminisce on your great(*n) grandpronoun whose progeny have built a thriving colony among the stars. Entire institutes would exist dedicated to collating and outlining the historical expansion of mankind among the stars, even if that knowledge takes centuries or millennia to accrue.
Also we can not say those other humans may as well not exist, because there is no telling what each new colony will go on to achieve. Their cultural, scientific and philosophical development independent of the influence of Earth's history and challenged by new environments could yield new perspectives, ways of thinking and practical inventions whose value far outweighs the large delay in communications.
If we're talking galactic scale, then the creatures who ultimately wind up on the other side of the Milky Way two hundred thousand years from now would likely bear only a passing resemblance to the humans who expanded from Earth. However barring a catastrophic event that erases their knowledge of their history, they would owe their existence in their history books to this tiny planet.
Finally, the fear that we are the only planet with human life would be vanquished, so even if we all died from pollution or meteorite, we'd know that somewhere the legacy of our species (and selected companion lifeforms) would continue, which I don't think is useless or meaningless either.
Re: Travel through wormholes is possible, but slow
#144Earlier quoted context omitted.
"Discoveries" about the mathematical structure of these theories are actually incredibly important even if no current day experiment can conceivably test them. Special and general relativity were discoveries made in this way (at least to an extent), and now general relativity is important for the proper functioning of technology as "trivial and boring" as GPS. Even earlier in our history, much of thermodynamics was d…
They're incredibly important, but they shouldn't be touted as facts until there's some consensus that they are facts
Mathematical theorems (especially no-go theorems, one of the most powerful tools in physics) are at least as much of a fact as an experimental measurement. I can concede that a pop-sci outlet should be clear about what is an experiment and what is a mathematical theorem, but was it really not clear in this case?
This is a sincere question, and I care to hear your opinion: do you believe that a reader of phys.org would need more than a glance at the article to know this is a discovery about the mathematics of general relativity, not an engineering breakthrough in the creation of a scifi-like hyperdrive?
Re: Travel through wormholes is possible, but slow
#145Earlier quoted context omitted.
The Average Null Energy Condition (ANEC) makes it so there can not be a traversable wormhole joining two otherwise disconnected regions of spacetime. So by construction, any infinite null geodesic (a light ray) which makes it through the wormhole must be chronal (causally connected). This means there can be no traveling faster than light over long distances by going through one.
So that's it, then? Some thing, say, a million light years away from another thing is in practice entirely inaccessible to civilizations existing on that other thing, requiring a minimum of a million years to reach?
>So that's it, then? Some thing, say, a million light years away from another thing is in practice entirely inaccessible to civilizations existing on that other thing, requiring a minimum of a million years to reach?
"We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far." -- H.P. Lovecraft, 'Call of Cthulhu'
We're just a random species of ape too smart for its own good, only here to ponder the universe at all because an asteroid happened to wipe out the dinosaurs 65 million years ago. The universe doesn't owe us anything.
At least we have telescopes and science fiction, though. The dinosaurs didn't have either.
Re: Travel through wormholes is possible, but slow
#146I'm not sure if this is the researchers' issue or is an issue with the scientific press, but it would help if the "discoveries" theorists made with their hitherto unestablished and untested theories like various string and QG based theories were not touted as discoveries about the real world.
I think it goes beyond the scientific press. There seems to be a general tendency to squash the intricacies of anything and react impulsively to some red herring or whatever; such comments dominate all online forums I've ever seen. Here is a fantastically interesting article that maybe has some new insight on the nature of spacetime; top comment on HN thread about it is some person loudly and incredibly pretentiously…
I really appreciate the clarity of this comment. While hacker news is certainly one of the better forums, the amount of armchair analysis and pseudointelectualism, especially on scientific non-IT posts, is pretty frustrating. It reminds of the "middlebrow dismissal" style https://news.ycombinator.com/item?id=5072224
Re: Travel through wormholes is possible, but slow
#147When ever I think of traveling through a wormhole/blackhole, I imagine you would be squished and crushed and come out the other end as pure vaporized energy. This makes me wonder, if there is the potential for our beings (or things) be able to be vaporized and then recreated to original form. If we are just mass and particles, this should be possible?
If you could 3d print things at the atomic level, then you could instantly advance the human race to a post scarcity society. It's the holy grail of 3d printing and of course everyone wants to do it. Your question has philosophical implications beyond just the mechanics, however.
>If you could 3d print things at the atomic level, then you could instantly advance the human race to a post scarcity society.
You still need energy, and you still need something to print with (not just the printer, but whatever substrate provides the atoms,) and the process is going to be somewhat inefficient due to thermodynamics. 3D printing a vegetable, likely, would still consume more resources than simply growing one in a garden. Plenty of room there for scarcity.
Re: Travel through wormholes is possible, but slow
#148Why doesn’t this violate the topological censorship result?
Re: Travel through wormholes is possible, but slow
#149I'm not sure if this is the researchers' issue or is an issue with the scientific press, but it would help if the "discoveries" theorists made with their hitherto unestablished and untested theories like various string and QG based theories were not touted as discoveries about the real world.
I think it goes beyond the scientific press. There seems to be a general tendency to squash the intricacies of anything and react impulsively to some red herring or whatever; such comments dominate all online forums I've ever seen. Here is a fantastically interesting article that maybe has some new insight on the nature of spacetime; top comment on HN thread about it is some person loudly and incredibly pretentiously…
IMO, your premise is a strawman. I don't detect any "it's just a theory" sentiment in the top level comment. What the comment says is that mathematical statements about "hitherto unestablished and untested theories" should not be taken as statements about the world.
This, to me, shows a rather sophisticated understanding of scientific truth, namely that we should demand that a scientific theory (as opposed to a mathematical construction) should be falsifiable. AFAIK, there is no question that the mathematics of string theory et. al is sound; the question is whether these theories are physical, and whether they are falsifiable. These are the exact objections the top-level comment makes when referring to "unestablished and untested theories".
Re: Travel through wormholes is possible, but slow
#150Earlier quoted context omitted.
They're incredibly important, but they shouldn't be touted as facts until there's some consensus that they are facts
Mathematical theorems (especially no-go theorems, one of the most powerful tools in physics) are at least as much of a fact as an experimental measurement. I can concede that a pop-sci outlet should be clear about what is an experiment and what is a mathematical theorem, but was it really not clear in this case? This is a sincere question, and I care to hear your opinion: do you believe that a reader of phys.org woul…
> Mathematical theorems (especially no-go theorems, one of the most powerful tools in physics) are at least as much of a fact as an experimental measurement
That's an overstatement. Measurements are more important than theory. We cannot form theories without measurements, and yes theories inform our measurements, but science always begins and moves forward with measurements.