DARPA funds all sorts of wacky far-future development work in the off chance that some of it actually becomes feasible, and at the very least they try to learn a bit more about how to make a successful flying car, or why it won't work without unobtanium.
But the fun thing about radiation is that you can stop any conceivable level of radiative flux simply by putting enough matter between it and you.
Not quite true. There is one exotic exception you overlooked... neutrino radiation.
Even if you used the entire mass of the universe to build a spherical radiation shield around you, it would only block a small fraction of neutrino radiation. Of course on the other hand neutrino radiation is quite harmless unless the radiative flux is insanely high. The only known natural source for dangerous levels of neutrino radiation would be a star going nova. So add stellar novas to the list of places you want to avoid in your interstellar spaceship:)
Interestingly, scientists have been considering building an artificial neutrino radiation beam for study, and they specifically analyzed the hazard level of the neutrino radiation it would generate. It turns out that if your bed were parked right over the local exit point, the neutrino radiation dose would be about 5 millisievert per year. This is about double the natural background radiation, and it is similar to receiving an X-ray per week. This is within occupational exposure levels, but such a worker would be required to wear a special badge to measure their radiation exposure.
So you can add "parking your interstellar ship on top of the proposed physics lab" to the list of things you want to avoid.:)
No good, a terrorist could just use an organic explosive. It doesn't matter if the passengers are unconscious, it could be detonated by a delay timer. You don't need any sort of detectable electronic timer either. You can simply have some organic substance that dissolves or gets digested over time to trigger the delayed detonation.
There is one way to achieve complete safety, and we already have the technology to do it. All we need to do is carpetbomb the United States with our nuclear arsenal. That would completely and permanently neutralize any possible threat. We'll finally be safe, no terrorist would ever kill an American again.
The ignorance of the law on/. is simply breathtaking.
I'm not sure whether to disagree and happily proclaim Slashdot to be vastly superior to virtually anywhere else, or whether to agree in despair that the rest of the world is vastly worse.
Sometimes the government does use its authority to run those lines over or under otherwise private land. However it's simpler just to talk about the usage of public land.
If a company wants a special government granted privilege to use that public land, and/or they want a government granted monopoly to serve and area, then the government has the right and the obligation to impose public-interest conditions. Requiring non-discriminatory service is probably the most obvious and essential condition.
Imagine you have phone service from AT&T, and Apple Computer corp has phone service from Verizon. Now picture AT&T started selectively sabotaging all of its own customer's phone connections to Apple. I'd like to see any Net Neutrality opponent even attempt to defend such a thing. And in any case the government is perfectly justified in prohibiting that sort of discriminatory service when phone companies do use public land to provide that service, and/or they receive any sort of government granted utility monopoly.
we can see galaxies moving away from us at several times the speed of light.
You were a little sloppy there:) What we actually SEE are galaxies a long time ago moving away from us at a large fraction of the speed of light. From that and other information we conclude that their speed away from us has increased above the speed of light since then, but we will only see them eternally inching closer to the speed of light.
can never understand that example, because it involves an error on the observers' part: they assume that the order they see photons from an event is the order the events occurred. FAIL.
No, look closely at The_train-and-platform_thought_experiment. In particular look at the diagrams. It's not based on when observers see photons from events. The diagram illustrates the instant the events happen, the instant the photons hit the ends of the traincar. From the diagrams you can see that for the observer in one frame of reference the photons actually hits the two ends of the car simultaneously. He can calculate precisely when those events are going to happen. After the events happen it will of course take additional time for him to see the reflected light coming from those events, but of course he will properly account for that time lag to view the result. And you can see for the observer in the other reference frame he too can calculate exactly when the two events are going to happen, and in his frame of reference those two events are going to have distinctly different timing. And yeah he too will have a delay before he sees the reflected light of those events, but that doesn't matter. He already knows the timing without needing to see it, and when he does see it of course he properly accounts for the time lag to see it.
In fact forget about seeing the events. The observers can set up event detectors with clocks to log the time of the events. Zero lag on logging the time of events.
Once you accept the bit of Relativity about moving clocks slowing down that really is all you need to show events occur in opposite orders for different observers. The clock distortion of Relativity doesn't just bend the meaning of time, it also bends the meaning of speed, it bends the meaning of distance and space. The physical distance between two events gets bent into different clock readings at the location of those events.
But there's no example of observer 1 seeing A happen before B, and observer 2 seeing B happen before A.
The traincar example has observer 1 seeing events A and B as simultaneous while observer 2 sees them as having an order. Lets say observer 2 has event A as happening 2 seconds before event B (it's a REALLY big traincar, grin). All we have to do is move the first person slightly off center in his traincar, so that in his frame the light reach side B 1 second before it reaches side A. Observer 2 still has event A as before event B, but now the difference is reduced to 1 second.
Now one person has event A as 1 second before event B, and the other has event B as 1 second before event A.
The other way to do it is just take the original traincar example and add a third person. This person is moving in the same direction as the traincar but at twice the speed. From his point of view he's not moving. From his point of view the traincar is moving in the opposite direction. In his frame of reference the light reaches the two ends of the car in the opposite order.
So you have three reference frames. One has A then B, one has A and B simultaneous, and one has B then A.
Let's try this: Let's say all stars die at exactly 6b years. First we would see our own supernova, then 6b years later, we would see the supernova of a star 6b lightyears away. Conversely, people at that star would see theirs first and ours second.
In you example you have only one frame of reference! The two observers my be sitting a hundred-trillion miles apart at two different stars, but neither of them is moving. That is the crucial point! If two observers are not moving, or if they are moving in the same direction at the same speed, then they are in the same frame of reference. They will completely agree on the timing of events.
In Relativity people only see a difference in timing when there is a difference in movement.
Lets say you're standing still and I'm on a train going west really fast. We see different "tilts" in the timeline of the universe. If we both look to the east, events there fall further into my past than they do for you. If we look to the west the opposite is true, future events there come into my present faster than they do for you.
You consider your "time" to be flat horizontal. An event a hundred miles to the west and and event a hundred miles to the east both happening "now" for you are like a horizontal timeline of "now". From your point of view my timeline is tilted uphill to the west. Your "now" event a hundred miles to the west is raised up into my future. Your "now" event to the easy has tilted down into my past.
From my point of view my train isn't moving, it's you and your train platform that are rocketing through space in the opposite direction. From my point of view my timeline is normal and horizontal. It seems to me that YOUR timeline view of the universe is what's tilted, and because you're going in the opposite direction your timeline is tilted up to the east and down to the west - the opposite way you thought mine was tilted. Our two timelines cross like an X. The crossing point of that X as at the moment you and I cross the same place at the same moment. You and I have the exact same meaning for "now" at that exact place and moment at the corner of the X. And if you picture that X on a sheet of paper, you can pick one line as horizontal and you can just rotate the paper a bit to see the other line as horizontal. Horizontal is east and west, and a horizontal line through the corner of the X means "now" at those places. Up and down on the paper is past and future. By rotating the paper a bit, events futher to the left or right are tilted up or down into the past or future.
The faster someone is moving the more tilted their timeline is. A critical point is that no one can move faster than light. That means there is a maximum amount their timeline can be tilted. Another important point is that when we
Personally I think this is the worst case of selective doctrine I've ever seen.
More like the best case of selective doctrine. A great moral advantage of being atheist is the easy "selective doctrine" of accepting what is right and good from all religions and philosophies.
Once you skip past the invisible-sky-wizard and the magic stuff elsewhere in the Bible, most atheists readily agree that Jesus taught a lot of really good things. In fact Thomas Jefferson published an edition of the Bible doing exactly that. A version of the Bible dedicated solely to Jesus's teachings and deleting deleting all the magical stuff. And as Jefferson put it, a REAL Christian is someone who follows the teachings of Christ. The fake Christians are the people preaching all that other Bible dogma, the stuff which Christ never said nor saw.
A Christian missionary once asked Ghandi "though you quote the words of Christ often, why is that you appear to so adamantly reject becoming his follower?" to which Ghandi replied "Oh, I don't reject your Christ. I love your Christ. It's just that so many of you Christians are so unlike your Christ".
Slashdot Mirror
when I boot to Windows, it never has any reason to mangle /dev/sdb, because it sees it as an unformatted D: drive.
[DRM author]
Oh look! An unformatted D: drive! The perfect unused place to overwrite with DRM data!
[/DRM author]
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Turn the fuck around and go straight.
It seems a lot of them are always trying so hard (and failing so hard) at that.
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The picture included with the linked article says it all, really.
Your puny Jedi mind tricks won't work on me.
I'm still not going to RTFA.
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DARPA funds all sorts of wacky far-future development work in the off chance that some of it actually becomes feasible, and at the very least they try to learn a bit more about how to make a successful flying car, or why it won't work without unobtanium.
U.S. Identifies Vast Mineral Riches in Afghanistan
Coincidence? I think not!
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Pavlov's Orgasm Recall Navigation.
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But the fun thing about radiation is that you can stop any conceivable level of radiative flux simply by putting enough matter between it and you.
Not quite true. There is one exotic exception you overlooked... neutrino radiation.
Even if you used the entire mass of the universe to build a spherical radiation shield around you, it would only block a small fraction of neutrino radiation. Of course on the other hand neutrino radiation is quite harmless unless the radiative flux is insanely high. The only known natural source for dangerous levels of neutrino radiation would be a star going nova. So add stellar novas to the list of places you want to avoid in your interstellar spaceship :)
Interestingly, scientists have been considering building an artificial neutrino radiation beam for study, and they specifically analyzed the hazard level of the neutrino radiation it would generate. It turns out that if your bed were parked right over the local exit point, the neutrino radiation dose would be about 5 millisievert per year. This is about double the natural background radiation, and it is similar to receiving an X-ray per week. This is within occupational exposure levels, but such a worker would be required to wear a special badge to measure their radiation exposure.
So you can add "parking your interstellar ship on top of the proposed physics lab" to the list of things you want to avoid. :)
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That yellow meter with the readout is showing the temperature of its output: yes, that's minus 40 degrees celcius.
Correction, it's minus 40 degrees fahrenheit.
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The puns just keep marching along.
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firing a shotgun into a swarm of gnats
Well ya gotta have something to do for entertainment after sex with the family gets boring and everyone runs out of "you might be a redneck" jokes.
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Back when I was a kid, Kirk was dating green women and Goatse was the frontier of strange URLs.
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Don't forget.... CARS are made out of parts too!
Someone could manufacture nuts or bolts that melt in the rain!
OHMYGOD! Cars are as dangerous as electronics!
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No good, a terrorist could just use an organic explosive. It doesn't matter if the passengers are unconscious, it could be detonated by a delay timer. You don't need any sort of detectable electronic timer either. You can simply have some organic substance that dissolves or gets digested over time to trigger the delayed detonation.
There is one way to achieve complete safety, and we already have the technology to do it. All we need to do is carpetbomb the United States with our nuclear arsenal. That would completely and permanently neutralize any possible threat. We'll finally be safe, no terrorist would ever kill an American again.
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Complex answer:
No+0i
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The ignorance of the law on /. is simply breathtaking.
I'm not sure whether to disagree and happily proclaim Slashdot to be vastly superior to virtually anywhere else, or whether to agree in despair that the rest of the world is vastly worse.
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Tea Baggers and ... Republicans
That's kinda like saying "Rabid Poodles and... Poodles".
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Sometimes the government does use its authority to run those lines over or under otherwise private land. However it's simpler just to talk about the usage of public land.
If a company wants a special government granted privilege to use that public land, and/or they want a government granted monopoly to serve and area, then the government has the right and the obligation to impose public-interest conditions. Requiring non-discriminatory service is probably the most obvious and essential condition.
Imagine you have phone service from AT&T, and Apple Computer corp has phone service from Verizon. Now picture AT&T started selectively sabotaging all of its own customer's phone connections to Apple. I'd like to see any Net Neutrality opponent even attempt to defend such a thing. And in any case the government is perfectly justified in prohibiting that sort of discriminatory service when phone companies do use public land to provide that service, and/or they receive any sort of government granted utility monopoly.
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About 12 out of the 20 posts so far all say the same thing. It's time to kill this entire story. It never should have appeared in the first place.
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Who is Hitler?
He's the guy who came up with the law "As an online discussion grows longer, the probability of a comparison involving Godwin approaches 1."
Why didn't you kill Goodwin??"
And I call Hitler's law on you.
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Well duh! As was already indicated, they were all lying cheating scum in illicit relationships.
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we can see galaxies moving away from us at several times the speed of light.
You were a little sloppy there :) What we actually SEE are galaxies a long time ago moving away from us at a large fraction of the speed of light. From that and other information we conclude that their speed away from us has increased above the speed of light since then, but we will only see them eternally inching closer to the speed of light.
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Why bother searching for each work of Shakespeare in Pi when you could just search for the INDEX listing the location of each work of Shakespeare?
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can never understand that example, because it involves an error on the observers' part: they assume that the order they see photons from an event is the order the events occurred. FAIL.
No, look closely at The_train-and-platform_thought_experiment. In particular look at the diagrams. It's not based on when observers see photons from events. The diagram illustrates the instant the events happen, the instant the photons hit the ends of the traincar. From the diagrams you can see that for the observer in one frame of reference the photons actually hits the two ends of the car simultaneously. He can calculate precisely when those events are going to happen. After the events happen it will of course take additional time for him to see the reflected light coming from those events, but of course he will properly account for that time lag to view the result. And you can see for the observer in the other reference frame he too can calculate exactly when the two events are going to happen, and in his frame of reference those two events are going to have distinctly different timing. And yeah he too will have a delay before he sees the reflected light of those events, but that doesn't matter. He already knows the timing without needing to see it, and when he does see it of course he properly accounts for the time lag to see it.
In fact forget about seeing the events. The observers can set up event detectors with clocks to log the time of the events. Zero lag on logging the time of events.
Once you accept the bit of Relativity about moving clocks slowing down that really is all you need to show events occur in opposite orders for different observers. The clock distortion of Relativity doesn't just bend the meaning of time, it also bends the meaning of speed, it bends the meaning of distance and space. The physical distance between two events gets bent into different clock readings at the location of those events.
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The traincar example is excellent.
But there's no example of observer 1 seeing A happen before B, and observer 2 seeing B happen before A.
The traincar example has observer 1 seeing events A and B as simultaneous while observer 2 sees them as having an order. Lets say observer 2 has event A as happening 2 seconds before event B (it's a REALLY big traincar, grin). All we have to do is move the first person slightly off center in his traincar, so that in his frame the light reach side B 1 second before it reaches side A. Observer 2 still has event A as before event B, but now the difference is reduced to 1 second.
Now one person has event A as 1 second before event B, and the other has event B as 1 second before event A.
The other way to do it is just take the original traincar example and add a third person. This person is moving in the same direction as the traincar but at twice the speed. From his point of view he's not moving. From his point of view the traincar is moving in the opposite direction. In his frame of reference the light reaches the two ends of the car in the opposite order.
So you have three reference frames. One has A then B, one has A and B simultaneous, and one has B then A.
Let's try this: Let's say all stars die at exactly 6b years. First we would see our own supernova, then 6b years later, we would see the supernova of a star 6b lightyears away. Conversely, people at that star would see theirs first and ours second.
In you example you have only one frame of reference! The two observers my be sitting a hundred-trillion miles apart at two different stars, but neither of them is moving. That is the crucial point! If two observers are not moving, or if they are moving in the same direction at the same speed, then they are in the same frame of reference. They will completely agree on the timing of events.
In Relativity people only see a difference in timing when there is a difference in movement.
Lets say you're standing still and I'm on a train going west really fast. We see different "tilts" in the timeline of the universe. If we both look to the east, events there fall further into my past than they do for you. If we look to the west the opposite is true, future events there come into my present faster than they do for you.
You consider your "time" to be flat horizontal. An event a hundred miles to the west and and event a hundred miles to the east both happening "now" for you are like a horizontal timeline of "now". From your point of view my timeline is tilted uphill to the west. Your "now" event a hundred miles to the west is raised up into my future. Your "now" event to the easy has tilted down into my past.
From my point of view my train isn't moving, it's you and your train platform that are rocketing through space in the opposite direction. From my point of view my timeline is normal and horizontal. It seems to me that YOUR timeline view of the universe is what's tilted, and because you're going in the opposite direction your timeline is tilted up to the east and down to the west - the opposite way you thought mine was tilted. Our two timelines cross like an X. The crossing point of that X as at the moment you and I cross the same place at the same moment. You and I have the exact same meaning for "now" at that exact place and moment at the corner of the X. And if you picture that X on a sheet of paper, you can pick one line as horizontal and you can just rotate the paper a bit to see the other line as horizontal. Horizontal is east and west, and a horizontal line through the corner of the X means "now" at those places. Up and down on the paper is past and future. By rotating the paper a bit, events futher to the left or right are tilted up or down into the past or future.
The faster someone is moving the more tilted their timeline is. A critical point is that no one can move faster than light. That means there is a maximum amount their timeline can be tilted. Another important point is that when we
Personally I think this is the worst case of selective doctrine I've ever seen.
More like the best case of selective doctrine. A great moral advantage of being atheist is the easy "selective doctrine" of accepting what is right and good from all religions and philosophies.
Once you skip past the invisible-sky-wizard and the magic stuff elsewhere in the Bible, most atheists readily agree that Jesus taught a lot of really good things. In fact Thomas Jefferson published an edition of the Bible doing exactly that. A version of the Bible dedicated solely to Jesus's teachings and deleting deleting all the magical stuff. And as Jefferson put it, a REAL Christian is someone who follows the teachings of Christ. The fake Christians are the people preaching all that other Bible dogma, the stuff which Christ never said nor saw.
A Christian missionary once asked Ghandi "though you quote the words of Christ often, why is that you appear to so adamantly reject becoming his follower?" to which Ghandi replied "Oh, I don't reject your Christ. I love your Christ. It's just that so many of you Christians are so unlike your Christ".
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Important note: The Westboro asshats want you to get violent at their protests. That way they can sue you to fund their activities.
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