I always say, if you go to war, the draft should be reinstated. Make it a fucking political nightmare to do it, and talking and peace will become more valuable.
The lack of a draft, and thus of troops, is one of the major reasons why the neocons didn't escalate their mid-east adventurism and press on into Iran before the reality of what a clusterfuck Iraq was had even begun to penetrate their thick skulls. It was physically impossible for them to do more than rattle sabers.
I get the idea of increasing the political cost of going to war with a draft, but it didn't stop Vietnam, it only increased their ability to prosecute it. In the post-'Nam era you could say the protests would be greater, but I say we still agreed to go to war. And losing an election in 2 or 4 years as the penalty for engaging in a war (if it turns out to be unpopular) doesn't sound like enough of a disincentive to me.
You want to present calling them maggot-infested as not hateful, and therefore are a liar. No meaningful conversation with a liar is or was ever possible. So bye.
I took from your explanation that you believe FTL can make you travel back in time.
You took correctly. Not arbitrary time travel -- it's limited by the speeds involved including the sub-luminal reference frames are traveling and for how long -- but more than enough to create causal paradoxes.
And it's not just me who believes this. Einstein and everyone else agrees -- google "speed of light causality" or "FTL time travel" to find ample sources.
Also, there's no reason to be a dick about my understanding of physics.
Sorry. That was meant to be more of a humorous reminder that the speed of light is not like the speed of anything in daily life, but it did come off as rather dickish.
The answer is "yes" he hates the people the same amount. That is, not
Bullshit. I know you want to parlay the admission of ignorance of his opinion on homosexuals into not actually having listened to him at all, but this is not true and you can't just lie to my face like that. He spoke on the subject more than often enough for your words to mean anything.
Just so you know, most people realize that calling weed evil isn't the same as calling the people who use it evil.
Yeah and calling them maggot-infested is both accurate and a compliment. LOL.
I didn't say he said they were "evil", I said he hates them, and he does. How much vitriol does someone have to spew at a group of people before it is clear that they hate them? The answer is much less than he has.
If you're going to do a word-mincing jerk-off session, at least make sure you're stroking the right verbiage.
Yeah, one of the last things I heard out of Sandia on the subject some years ago (maybe '08? Nope, actually all the way back in 2007) was them turning the electrical pulse circuitry into a "lunchbox"-size unit that could be stacked in parallel with others, and rapid fired. And it was like "yeah, yeah, road to economical fusion power blah blah blah where are the sparkies?"
I'd suggest that they should keep the old Z-machine running for tourists to ooh and ahhh over on tours of the production fusion reactor (it's not like they won't have the power to run it), but as the world's largest source of X-rays that's probably not a good idea either.
But I do know what he has said about druggies, and his opinion of them is not open to question here. So, same question, but this time can I get a non-masturbatory answer?
I think the last time I actually listened to Rush was in 1997, so I really can't remember... does he hate teh gays as much as teh druggies? I'm just asking.
If I'm reading this all correctly the whole point of relativity is that there is no such thing as absolute time.
Yes, but also that everyone's individual clocks are correct. Everyone must agree that cause happens before effect, but everyone having different notions of time is how FTL travel lets you break cause and effect.
Yeah, I remember when we had the MIT fusion research Slashdot Interview, and they showed the graph that was presented in the 70s showing how soon they could have fusion given various funding levels.
The saddest part was of the various scenarios like "fusion in 10 years", "fusion in 20 years", there was a "fusion never" line where funding was never sufficient to yield breakeven fusion, and then there was overlaid a new "actual funding" line which was significantly lower than that.:(
P.S. Personally my money is on Sandia, but that's just because the old Z-Machine was the most fucking awesome thing ever. EVER. I admit this is not a rational scientific argument, and that a working Z-pinch fusion device would not look like that at all, but come on!
A simulation shows that experiments scheduled for next year could work.
Not exactly. This was an actual experiment showing that previously done simulations were correct. They needed to figure out the correct thickness to make the liners to balance implosion speed with vaporization due to extreme current, the simulations said this was a sweet spot, and the experiment said that indeed this would work.
Of course this is just one more step in the design - simulate - experiment cycle, but still, at least it is about a real result.
Also, I'm just glad to be hearing about further progress from the Z-Machine folks at Sandia since I hadn't in quite a while. So even though it's not the final goal, it's still good news.
It would be the same if the "speed of mail" were a universal constant observed to be the same from all inertial reference frames, such that even if you traveled very rapidly, you would still see the mail traveling ahead of you by the same amount as you did when you were at rest with respect to the earth. Then one would be forced to conclude that space-time is not absolute and instead is relative to the proportion of your velocity to that of the mail, and that therefore if one could actually travel faster than mail, some observers would see this as traveling back in time and by using several such journeys you could actually create a causal paradox.
Then they'd be the same, yes.;)
You can't use your Newtonian intuition to explain FTL travel, sorry.
I'm a little confused by this idea. At no point does the warp ship go from point A to point B faster than light would travel the same distance. The path that the ship takes is shorter than the path that the light takes. The distance is not equal.
Right, the ship in its own reference frame -- the warped space bubble -- would not be traveling faster than light.
But in Relativity, all reference frames are equal. The laws of physics must appear to be obeyed according to all of them.
And a reference frame that is somewhere else would observe the ship leave A and arrive at B faster than light, because from their reference frame A and B are separated by their "usual" distance. The warp bubble effect is a local effect, only experienced by the warp ship itself.
If an observer were near point B, I can see how it might appear that the ship arrived before it left. However, this would be an optical illusion based on the greater distance that the light traveled.
It's actually not an illusion, as the speed of light is intimately related to the notion of time in relativity. Things get even worse if the points A and B are not at rest relative to each other and instead are moving at relativistic (but sub-luminal) velocity. Then the difference between A and B's space-time axes would allow another FTL trip from B to A to actually arrive back at A before it left A in the first place.
Causality was already broken, but now we've created a paradox.
What method could they possibly use to observe you travelling faster than light?
Sorry, I don't mean literally observe you in transit breaking the universal speed limit.
All that is required is that they see two causally linked events -- you getting into the spaceship at one place, and getting out at another -- which have a "space-like" separation according to their reference frame. Meaning according to their view of space-time, the two events were farther apart in distance and closer in time than would be allowed by the speed of light.
This is why "cheating" by using a warp drive doesn't actually help you get around causality issues. The observer doesn't care how you got from A to B, they only care that the two events had a space-like interval from their reference frame.
Of course if the warp ship never stops, and therefore is never visible or capable of interacting with anything in it's "past" ever again, then you never see this and there is no problem.
How can you have two objects moving away from each other at greater than the speed of light, whilst maintaining special relativity?
By having it be impossible for those two objects to interact. As SciBrad said, those objects are past an event horizon, and are as unreachable to us as the interior of a black hole.
This is also the simplest explanation for the causality implications of an Alcubierre drive -- the interior of the warped space is causally separated from the rest of space-time, and there's no known way to enter or exit it. So you can travel "FTL" but you can't actually interact with anything.
It surely does, but it would actually be after the true "capable of observing" sense determined by the speed of light in a vacuum. As in if the actual return of a sample occurs FTL then you're really screwed.
The thing is, given a couple regular spaceships and a couple warp ships to act as relays between them, you could actually create a scenario where the sample is returned before the original warp ship left. As soon as you open up causally connected FTL travel you open the door to causal paradoxes.
But what you're saying is that appearances are all that matters
I'm not intending to do so in the trivial sense of "just appearances".
But I am in the deeper, physical sense that different reference frames have different notions of space-time and thus the ordering of events. And all such reference frames views of event ordering are "correct" and must obey the laws of physics. This is the basis of Relativity -- it's literally the Relativity in the Theory of Relativity.
It does not appear to ANYONE that I've traveled faster than light, as long as they understand what's going on.
Yes it does. The shortening of the distance between A and C is a local effect only. Only you in your warp ship's reference frame is the distance shortened. Every other reference frame in the universe sees the distance from A to C as greater than what your travel time would allow at the speed of light. Not in a superficial "appears to be but really isn't", but in an actual, "that's how space-time actually is from their reference frame" sense.
And given a couple such warp ships, and a couple sub-luminal rocket ships, you could send messages between them such that the first message sent receives a response before it is sent.
What you're saying is that even though we've created a causal paradox according to multiple reference frames, because they "know" that according to your local reference frame you did not travel faster than light, the message that is in their hand doesn't exist and the paradox did not occur.
This is untrue. All reference frames are valid. "Knowing" that the laws of physics were obeyed in yours does not matter. They do not care that you used a "trick", you violated causality according to their reference frames.
Notice that in this example, the actual method of FTL travel/communication is irrelevant. They use the "ansible", an instantaneous communication device, but it could be warp ships or transporters or wizards for all it matters. The point is what the inertial observers in sub-luminal reference frames see -- and they'd see causality violated.
Time dilation and other such effects would not happen. Its why wormholes do NOT violate relativity.
Ah, but given FTL travel/communication, and regular sub-luminal reference frames which do experience time dilation, you can use the FTL to send a message and a response that will be received before the original message was sent. Paradox.
Note that in the explanation of how this occurs, it does not matter how the FTL is achieved. All that matters is that the sub-luminal observers see information pass from A to B faster than light.
Events happening out of causal order according to any observer is technically a violation of causality. What you've done is taken advantage of causality violation to create a paradox, which is a much more obvious problem.
The key word there is "before I saw you leave." , not "before you left." Human vision and radio receivers are not the arbiters of time.
But the speed of light in a vacuum is. You're thinking of time as if there is a universal clock by which the timing and thus ordering of events can be measured irrespective of observation from . This is pre-Relativity thinking. In Relativity the passage of time is relative, all observer's clocks are valid, and the speed of light determines the earliest that an event is capable of affecting you (even if you don't actually "see" the event).
Two observers in different reference frames will disagree on the relative timing of two events depending on their velocities with respect to the source of the event. However for all events with a "time-like" separation, meaning the time and distance is such that a signal traveling at the speed of light could go from one event to the other in that time, they will agree on the order. These are the events that can possibly have a causal relationship.
For events that have a "space-like" interval (ones that do not obey d <= t*c), however, observers in different frames will disagree on the ordering of events. This is okay as long as there is no causal relationship, but if there is then it causes problems.
While it may not be obvious how being able to observe someone arriving at their destination before they leave violates causality ("all you're doing is seeing it, that doesn't mean that's what happened"), the timing of events is defined in relativity by when you are capable of observing them. And this has real meaning because with the help of a couple Warp Drives, and a couple "regular" space ships traveling at high but sub-luminal velocity, you can take advantage of time dilation and create a closed causal loop -- sending yourself a message before you've written it. An obvious violation of causality.
Here is an explanation for how you accomplish that. Or you can just google "speed of light causality" for many other explanations. Suffice to say the link between causality violation and FTL travel is well known.
How do you explain the current astrophysical consensus, that distant galaxies are traveling several times faster then light (and speeding up) from us due to our universe expanding exponentialy?
It's actually expanding linearly, but over large distances this adds up.
And the explanation is simple: Because these objects are moving away from us faster than light, we cannot ever see them or interact with them. No observation or experiment can ever be affected by them. They're out of the observable universe.
So we can infer that they are travelling faster than light, but we can't ever observe this, and so there is no causality problem.
Slashdot Mirror
I always say, if you go to war, the draft should be reinstated. Make it a fucking political nightmare to do it, and talking and peace will become more valuable.
The lack of a draft, and thus of troops, is one of the major reasons why the neocons didn't escalate their mid-east adventurism and press on into Iran before the reality of what a clusterfuck Iraq was had even begun to penetrate their thick skulls. It was physically impossible for them to do more than rattle sabers.
I get the idea of increasing the political cost of going to war with a draft, but it didn't stop Vietnam, it only increased their ability to prosecute it. In the post-'Nam era you could say the protests would be greater, but I say we still agreed to go to war. And losing an election in 2 or 4 years as the penalty for engaging in a war (if it turns out to be unpopular) doesn't sound like enough of a disincentive to me.
You want to present calling them maggot-infested as not hateful, and therefore are a liar. No meaningful conversation with a liar is or was ever possible. So bye.
I took from your explanation that you believe FTL can make you travel back in time.
You took correctly. Not arbitrary time travel -- it's limited by the speeds involved including the sub-luminal reference frames are traveling and for how long -- but more than enough to create causal paradoxes.
And it's not just me who believes this. Einstein and everyone else agrees -- google "speed of light causality" or "FTL time travel" to find ample sources.
Also, there's no reason to be a dick about my understanding of physics.
Sorry. That was meant to be more of a humorous reminder that the speed of light is not like the speed of anything in daily life, but it did come off as rather dickish.
The answer is "yes" he hates the people the same amount. That is, not
Bullshit. I know you want to parlay the admission of ignorance of his opinion on homosexuals into not actually having listened to him at all, but this is not true and you can't just lie to my face like that. He spoke on the subject more than often enough for your words to mean anything.
Just so you know, most people realize that calling weed evil isn't the same as calling the people who use it evil.
Yeah and calling them maggot-infested is both accurate and a compliment. LOL.
I didn't say he said they were "evil", I said he hates them, and he does. How much vitriol does someone have to spew at a group of people before it is clear that they hate them? The answer is much less than he has.
If you're going to do a word-mincing jerk-off session, at least make sure you're stroking the right verbiage.
Yeah, one of the last things I heard out of Sandia on the subject some years ago (maybe '08? Nope, actually all the way back in 2007) was them turning the electrical pulse circuitry into a "lunchbox"-size unit that could be stacked in parallel with others, and rapid fired. And it was like "yeah, yeah, road to economical fusion power blah blah blah where are the sparkies?"
I'd suggest that they should keep the old Z-machine running for tourists to ooh and ahhh over on tours of the production fusion reactor (it's not like they won't have the power to run it), but as the world's largest source of X-rays that's probably not a good idea either.
But I do know what he has said about druggies, and his opinion of them is not open to question here. So, same question, but this time can I get a non-masturbatory answer?
I think the last time I actually listened to Rush was in 1997, so I really can't remember... does he hate teh gays as much as teh druggies? I'm just asking.
Thanks!
If I'm reading this all correctly the whole point of relativity is that there is no such thing as absolute time.
Yes, but also that everyone's individual clocks are correct. Everyone must agree that cause happens before effect, but everyone having different notions of time is how FTL travel lets you break cause and effect.
Yeah, I remember when we had the MIT fusion research Slashdot Interview, and they showed the graph that was presented in the 70s showing how soon they could have fusion given various funding levels.
The saddest part was of the various scenarios like "fusion in 10 years", "fusion in 20 years", there was a "fusion never" line where funding was never sufficient to yield breakeven fusion, and then there was overlaid a new "actual funding" line which was significantly lower than that. :(
P.S. Personally my money is on Sandia, but that's just because the old Z-Machine was the most fucking awesome thing ever. EVER. I admit this is not a rational scientific argument, and that a working Z-pinch fusion device would not look like that at all, but come on!
A simulation shows that experiments scheduled for next year could work.
Not exactly. This was an actual experiment showing that previously done simulations were correct. They needed to figure out the correct thickness to make the liners to balance implosion speed with vaporization due to extreme current, the simulations said this was a sweet spot, and the experiment said that indeed this would work.
Of course this is just one more step in the design - simulate - experiment cycle, but still, at least it is about a real result.
Also, I'm just glad to be hearing about further progress from the Z-Machine folks at Sandia since I hadn't in quite a while. So even though it's not the final goal, it's still good news.
It would be the same if the "speed of mail" were a universal constant observed to be the same from all inertial reference frames, such that even if you traveled very rapidly, you would still see the mail traveling ahead of you by the same amount as you did when you were at rest with respect to the earth. Then one would be forced to conclude that space-time is not absolute and instead is relative to the proportion of your velocity to that of the mail, and that therefore if one could actually travel faster than mail, some observers would see this as traveling back in time and by using several such journeys you could actually create a causal paradox.
Then they'd be the same, yes. ;)
You can't use your Newtonian intuition to explain FTL travel, sorry.
I'm a little confused by this idea. At no point does the warp ship go from point A to point B faster than light would travel the same distance. The path that the ship takes is shorter than the path that the light takes. The distance is not equal.
Right, the ship in its own reference frame -- the warped space bubble -- would not be traveling faster than light.
But in Relativity, all reference frames are equal. The laws of physics must appear to be obeyed according to all of them.
And a reference frame that is somewhere else would observe the ship leave A and arrive at B faster than light, because from their reference frame A and B are separated by their "usual" distance. The warp bubble effect is a local effect, only experienced by the warp ship itself.
If an observer were near point B, I can see how it might appear that the ship arrived before it left. However, this would be an optical illusion based on the greater distance that the light traveled.
It's actually not an illusion, as the speed of light is intimately related to the notion of time in relativity. Things get even worse if the points A and B are not at rest relative to each other and instead are moving at relativistic (but sub-luminal) velocity. Then the difference between A and B's space-time axes would allow another FTL trip from B to A to actually arrive back at A before it left A in the first place.
Causality was already broken, but now we've created a paradox.
What method could they possibly use to observe you travelling faster than light?
Sorry, I don't mean literally observe you in transit breaking the universal speed limit.
All that is required is that they see two causally linked events -- you getting into the spaceship at one place, and getting out at another -- which have a "space-like" separation according to their reference frame. Meaning according to their view of space-time, the two events were farther apart in distance and closer in time than would be allowed by the speed of light.
This is why "cheating" by using a warp drive doesn't actually help you get around causality issues. The observer doesn't care how you got from A to B, they only care that the two events had a space-like interval from their reference frame.
Of course if the warp ship never stops, and therefore is never visible or capable of interacting with anything in it's "past" ever again, then you never see this and there is no problem.
I'm so disappointed the top link isn't to the Superfriends episode where a space monster hatches out of the moon. :(
The salient point being that it is underneath, not on top.
Hm, that's not very flame-y... Don't want to disappoint...
Ah! Cheesecake flambe! It might have a thin seared crust on top!
How can you have two objects moving away from each other at greater than the speed of light, whilst maintaining special relativity?
By having it be impossible for those two objects to interact. As SciBrad said, those objects are past an event horizon, and are as unreachable to us as the interior of a black hole.
This is also the simplest explanation for the causality implications of an Alcubierre drive -- the interior of the warped space is causally separated from the rest of space-time, and there's no known way to enter or exit it. So you can travel "FTL" but you can't actually interact with anything.
It surely does, but it would actually be after the true "capable of observing" sense determined by the speed of light in a vacuum. As in if the actual return of a sample occurs FTL then you're really screwed.
The thing is, given a couple regular spaceships and a couple warp ships to act as relays between them, you could actually create a scenario where the sample is returned before the original warp ship left. As soon as you open up causally connected FTL travel you open the door to causal paradoxes.
But what you're saying is that appearances are all that matters
I'm not intending to do so in the trivial sense of "just appearances".
But I am in the deeper, physical sense that different reference frames have different notions of space-time and thus the ordering of events. And all such reference frames views of event ordering are "correct" and must obey the laws of physics. This is the basis of Relativity -- it's literally the Relativity in the Theory of Relativity.
It does not appear to ANYONE that I've traveled faster than light, as long as they understand what's going on.
Yes it does. The shortening of the distance between A and C is a local effect only. Only you in your warp ship's reference frame is the distance shortened. Every other reference frame in the universe sees the distance from A to C as greater than what your travel time would allow at the speed of light. Not in a superficial "appears to be but really isn't", but in an actual, "that's how space-time actually is from their reference frame" sense.
And given a couple such warp ships, and a couple sub-luminal rocket ships, you could send messages between them such that the first message sent receives a response before it is sent.
What you're saying is that even though we've created a causal paradox according to multiple reference frames, because they "know" that according to your local reference frame you did not travel faster than light, the message that is in their hand doesn't exist and the paradox did not occur.
This is untrue. All reference frames are valid. "Knowing" that the laws of physics were obeyed in yours does not matter. They do not care that you used a "trick", you violated causality according to their reference frames.
Fortunately the "speed of post" is not a physically significant value with no effect on the relative passage of time. The speed of light, however, is.
Here's one such explanation.
Notice that in this example, the actual method of FTL travel/communication is irrelevant. They use the "ansible", an instantaneous communication device, but it could be warp ships or transporters or wizards for all it matters. The point is what the inertial observers in sub-luminal reference frames see -- and they'd see causality violated.
I'd love to see your explanation of how a ship jumping around the universe would arrive back before it left.
Here's one with pretty graphs, but just googling it would show that this is correct.
Time dilation and other such effects would not happen. Its why wormholes do NOT violate relativity.
Ah, but given FTL travel/communication, and regular sub-luminal reference frames which do experience time dilation, you can use the FTL to send a message and a response that will be received before the original message was sent. Paradox.
Note that in the explanation of how this occurs, it does not matter how the FTL is achieved. All that matters is that the sub-luminal observers see information pass from A to B faster than light.
Events happening out of causal order according to any observer is technically a violation of causality. What you've done is taken advantage of causality violation to create a paradox, which is a much more obvious problem.
The key word there is "before I saw you leave." , not "before you left." Human vision and radio receivers are not the arbiters of time.
But the speed of light in a vacuum is. You're thinking of time as if there is a universal clock by which the timing and thus ordering of events can be measured irrespective of observation from . This is pre-Relativity thinking. In Relativity the passage of time is relative, all observer's clocks are valid, and the speed of light determines the earliest that an event is capable of affecting you (even if you don't actually "see" the event).
Two observers in different reference frames will disagree on the relative timing of two events depending on their velocities with respect to the source of the event. However for all events with a "time-like" separation, meaning the time and distance is such that a signal traveling at the speed of light could go from one event to the other in that time, they will agree on the order. These are the events that can possibly have a causal relationship.
For events that have a "space-like" interval (ones that do not obey d <= t*c), however, observers in different frames will disagree on the ordering of events. This is okay as long as there is no causal relationship, but if there is then it causes problems.
While it may not be obvious how being able to observe someone arriving at their destination before they leave violates causality ("all you're doing is seeing it, that doesn't mean that's what happened"), the timing of events is defined in relativity by when you are capable of observing them. And this has real meaning because with the help of a couple Warp Drives, and a couple "regular" space ships traveling at high but sub-luminal velocity, you can take advantage of time dilation and create a closed causal loop -- sending yourself a message before you've written it. An obvious violation of causality.
Here is an explanation for how you accomplish that. Or you can just google "speed of light causality" for many other explanations. Suffice to say the link between causality violation and FTL travel is well known.
How do you explain the current astrophysical consensus, that distant galaxies are traveling several times faster then light (and speeding up) from us due to our universe expanding exponentialy?
It's actually expanding linearly, but over large distances this adds up.
And the explanation is simple: Because these objects are moving away from us faster than light, we cannot ever see them or interact with them. No observation or experiment can ever be affected by them. They're out of the observable universe.
So we can infer that they are travelling faster than light, but we can't ever observe this, and so there is no causality problem.