The more I read, the more it looks like it should be possible to "backport" birds to a surprising degree even without any unobtanium "dinosaur DNA". Even without studying what specific genes do, we can already start by comparing different lineages to see what genetic shifts in birds occurred between their theropod ancestors and modern descendents (for example, if most other groups of animals, including alligators, have a certain gene but birds don't, then that change occurred at some point on the bird side of the branching point between birds and alligators). Looking at modern descendents won't give us an exact picture of their common ancestors, but it'll certainly let us role back a lot of the changes. Combining that with reasoning out and experimenting with what morphological changes in birds that differ from dinosaurs are the result of what genes... we should be able to come up with something rather close to their ancestors at different stages.
It's amazing how much detail they're starting to be able to determine about ancient species - even to the point of being able to determine the number of wing quill feathers in velociraptors. We're certainly constraining the reversal problem more and more.
Oh god, I just had a terrifying thought... A T-Rex with the threat gestures of an Amazon. For those who don't own Amazon parrots, when they get overexcited or aggressive, they not only do this fantail display, but they have this creepy thing that they do with their eyes where they make their pupils expand and contract. Picture this, but with the pupil repeatedly changing in size 3x while it stares at you. It basically means "This is my Crazy Time. Go on, try coming close to me, see what happens!" They really lose their mind during it - for example, they may go into Crazy Mode because you gave them some treat that got them overexcited, but because they can't think straight, they're prone to drop and lose whatever it was that you gave them.
But yeah... crazy T-rex flaring whatever feathers it has and giving you an unflinching death stare with giant pulsating yellow eyes.
My parrot can take the backs off my earrings and take my earrings out without eating the backs or damaging my ears. He can open clasps on my clothes. No question that their beaks are dexterous.
However, I think the author was actually referring more to "adaptable". Bird beaks come in all sorts of shapes, apparently achieved by relatively simple genetic tweaks that allows them to adapt quickly (in evolutionary terms) to changing food sources.
Well.... any long-term confined high temperature isotropic quasi-neutral maxwellian plasma has to be large. Of course, if you start changing those requirements, you start changing the required size for your reactor. It's not theoretically impossible to have a viable fusion power plant that does not follow those constraints; the challenge is achieving it without either imposing a new, even more onerous series of challenges on yourself. Drop the concept of long-term confinement (for example, inertial confinement) and you find yourself with incredibly extreme compression challenges and having to deal with blowing your target apart on every fire. Don't use a quasi-neutral plasma and the plasma density drops by orders of magnitude, meaning your fusion rate drops so low that even little losses in the system will kill the concept. Don't use a maxwellian plasma and you have to find a way to hold the plasma away from thermalization without wasting more energy than the fusion yield, which is impossible by simply applying energy to part or all of the plasma - it's only even theoretically possible if you accelerate only the highest energy ions, creating a plasma only slightly skewed from a thermal distribution, and even if you have such a means, it's not easy. And so forth. You can remove constraints on fusion but then you get hit by others.
Unlike many here, I don't see it as an impossible problem simply because it hasn't been made economical yet despite decades of work. Because in those decades of work there's been orders of magnitude improvement, and I don't see those improvements just suddenly ceasing across every line of research. But no question, this is a Difficult Problem(TM).
No, I haven't submitted a paper on it. It's just a concept that I'm still working on at this point, and I want to have a proper simulation to back it up.
Oh, god, space technology is full of brilliant hacks. For example, New Horizons' radio. It has two amps connected to one dish, designed as a primary and a backup. But while it was en route, an engineer hit upon an idea to have them both transmit at the same time through the same dish, doubling the bandwidth. Normally that wouldn't make sense, except that the amplifiers have signals with different polarization, and these can be separated back out on Earth.
Great, except for one problem. The second radio was designed as a backup, they weren't planned for simultaneous operation - so there's not enough power to run them both and everything else at the same time. There's barely enough power to run just the radios - and I mean, it's not like you can just shut off the flight computer to free up more power. Well... actually, that's exactly what they do. When have a ton of data accumulated that they want to get to Earth and no critical science to do, they spin the craft up like a bullet to keep it stable and the dish pointing at Earth. Then they shut down the whole guidance and control system and pretty much everything else on the craft not essential for reading and transmitting data. It stays in this mode for days for a week or two, until all of the onboard data is transmitted, then they spin it back down so that they can do things like take pictures once again.
Quite a few of us how have them, yes and that includes "environmentalists". Sure, they're not without their problems, environmentally, but they have a quite a few upsides as well.
What sort of environmentalists have you been hanging around with? Environmentalist opposition to dams is so well known that "blowing up dams" is one of the cliche stereotypes of "eco-terrorists".
The aspect of Price-Anderson that people complain about is that the US government foots the bill for the vast majority of costs in the event of a catastrophic accident.
Sure, but what I was pointing out (in a roundabout way), is that the same is effectively true of any large scale infrastructure system, especially when it comes to power generation on a massive scale. Doesn't matter if the cost comes from a hydro electric dam that fails, or a coal ash slurry dam failure, or a major oil spill, or indeed a release of radio nucleotides.
What on Earth are you talking about? Did the government foot the bill after the Deepwater Horizon incident? After any of the coal ash slurry failures? Of course not, the companies responsible did, and it cost them an utter fortune. The difference here is that unlike with nuclear power, their liability is uncapped. With nuclear power, the liability in the case of catastrope is a cost borne by taxpayers.
If that much money is at stake there are many ways for those that earn money off of the business to protect themselves from damage. Bankruptcy is always cheaper than insurance.
Which is why BP and the coal mining companies responsible are now bankrupt?
And FYI, industries carrying major risk are effectively required to have what amounts to insurance against those who go bankrupt. It's called Superfund, and it's supported by taxes on polluting industries - a "polluter pays" principle. Price-Anderson is based on a "public pays" principle. The money to cleanup in the event of a major nuclear disaster (over $12B) doesn't even come from a levy on the nuclear power industry. In fact, there is no money there for such a cleanup, the government is just supposed to come up with it if it happens. Fukushima for example is expected to cost over $100B in direct cleanup costs alone, let alone the much larger potential liability for claims.
So, it doesn't matter if the nuclear industry doesn't have insurance, since many/most other human endeavours on that scale doesn't either.
To wit the Exxon Valdes spill and the legal aftermath. It didn't seem to hurt Exxon nearly as much as it did Prince William sound.
To wit, once again, the company didn't go bankrupt. They minimized the cost through a very effective legal campaign, of course. The government did not socialize the damages; it remained their responsibility to pay them. The fact that they managed to weasel out of having to pay a lot of what they should have paid doesn't change who the responsible party was. Nor does it make it logical that the solution to companies like Exxon weaseling out of payments is to have the government assume liability for major disasters and let those who caused them off the hook.
The Soviets were hardly unique in terms of bad reactor design. Have you seen the design used for the British Windscale plant? It makes you want to hit your head against a wall when you read it. They literally just stuck canisters of fuel into holes in the wall, hit them in by hand with ram rods, and hoped that the old canisters would fall out the back into a narrow trench of water. The designers got mad and nearly derailed it when one physicist wanted to put a really trivial pollution scrubber on the stack; they taunted him over it afterwards for wasting money. Now, saying "canisters" makes it sound fancier than they were, they were basically glorified aluminum cans full of highly flammable uranium, stuck into a hot reactor. Then they changed their fuel mix that they put inside without redoing any of the engineering. Including having them full of more flammable stuff like lithium and magnesium metal. And then they cut off the cooling fins from the canisters. Their monitoring was so poor that when the system inevitably caught fire they didn't notice it for days. They then went down there and started poking around in a hole with the ramrod; it came out covered in molten uranium.
Chernobyl was a paragon of safety compared to Windscale.
Yeah, it seems thorium has become the nuclear-reactor-hype of the day, the ShinyNewTech replacing PBMRs. The pattern repeats. I wish these people would at least google "ShinyNewTech disavantages" before spouting off about how ShinyNewTech is the savior of the world.
First off, who's extolling the virtues of hydroelectric dams? Dams usually fall on environmentalists' hate lists at around the same place as coal, give or take a few slots.
Extolling the virtues of wind or solar, yeah. But you better believe a wind farm operator will be sued if a turbine falls on someone's house, or a solar thermal plant if their mirrors misalign and blind a pilot. And for that matter, you better believe that a hydroelectric dam operator will be sued if their dam breaks (at least in the first world). And most companies willingly insure their large projects as a hedge against risk.
The aspect of Price-Anderson that people complain about is that the US government foots the bill for the vast majority of costs in the event of a catastrophic accident. The power plant operators only need to insure enough to foot the bill to insure against minor accidents, something most operators would want to do anyway to protect themselves. Many people find the capped liability to be a highly distorting influence on the market, socializing the risks while keeping the profits private.
The waste issue (as well as inherent safety) is part of the reason that there's so much research on ADSRs right now (note: the article says that an ADSR "would use thorium as a fuel", but it's not actually limited to thorium, it can use any subcritical fissile core). Spallation can rip apart the long-lived actinides that don't have a sufficient (n, gamma) cross section to prevent their accumulation in nuclear waste. And of course, since the core is inherently subcritical by design, simply not enough neutronicity under any condition to sustain a chain reaction on its own, when you shut the beam off, fission ceases instantly (though you still have decay heat like with any other nuclear power plant). Spallation source provides no more than about 10% or so of the neutronicity, but it's the amount needed to push the core over the edge.
I have my own very radical variant on the concept of an accelerator driven fission that I'm working on simulating now in Geant4 (although that was probably a poor choice of software, apparently their thermal scattering codes are really immature... as far as CERN is concerned, once particles get down below the MeV range they're usually not particularly interesting). But anyway the concept is to have a core with literally zero neutronicty - a lithium-burning reactor. The basic concept is as such:
1. A planar proton beam is delivered by one or more high power linac beamlines. Commercial-scale linac costs - without any improvements in technology - are expected to cost $5-20 per watt. The particular design would call for very high voltage (~16MV) klystrons to drive it - and not simply to reduce size (more in this shortly)
2. The proton beam bombards a fragment emitting target inside an axial magnetic field in a vacuum. The estimation of deceleration efficiency is estimated at over 90% in fragment reactors due to the lack of Carnot losses (according to the published research on the subject). The resultant HVDC will be direct converted to the klystron voltage in producing the electron beam that drives the linac. About 60% of the energy of spallation goes into fragment production. Fragments will be drawn away from the fragment target en route to the collector via a slightly expanding axial magnetic field. Fragment collection allows for automatic isotope separation.
3. The maximum power output of a fragment reactor is limited by its surface area and its ability to radiate heat. Fragment-emitting targets can be either electrostatically suspended dust or rapidly rotating with thin fibers or planes of target material, in order to radiatively cool without melting. Spallation targets, for efficiency, need to be high-Z materials, such as lead, tungsten, mercury, etc. Tungsten is particularly attractive due to its high melting point of 3695K. High-Z metal-rich ceramics are also possible targets, with very high melting points. The temperature of the chamber's beryllium walls being radiated to will be around 1050K. This means heat exchange between a ~3000K emitter (4.6e7W/m) and a 1050K receiver (6.8e4W/m), or about 4.5MW per square meter. In short, this allows for a surprisingly compact core, limited more by the length necessary to ensure a sufficient proton spallation cross section.
4. Neutrons emitted by spallation (at a cost of 30-40 MeV per neutron) are heavily biased by
You can see the parameters, the cost of Price-Anderson covering them in the event of a catastrophic accident beyond the minimums is not covered.
Also, people should be careful not to confuse the prices on the calculator with the price of electricity that they pay. Power plant generation costs and consumer purchase rates are not the same thing. Industrial rates are at least closer to generation costs, but even they add a couple cents per kWh to the cost.
Have you never seen anything about the twin paradox? Even at the most superficial level introduction of relativity, you get that time slows down when something is moving relative to the observer.
This is ridiculous. Even "at the most superficial level introduction of relativity "you should know that if a person departs earth moving at "nearly C" and comes back, far less time will have past for them than someone who stayed on Earth the whole time.
From the perspective of the people on the ship, the journey is no longer a distance of 4.3 light years. If the spaceship is going 90% of c relative to Earth, then in the spaceship's frame it will take them 2.08 years to make that trip, and also in their frame they will observe it takes light 1.87 years to go from Earth to Alpha-Centari.
First off, apart from trying to add confusion, why did you change the velocity from the one I gave? Secondly, from a trip travel time perspective, it doesn't matter whether you view it as time dilation or length contraction. The trip at 0.999c takes 70 days from the perspective of the crew. That's the beginning and end of it right there. From their perspective, it's as if they got there moving far faster than the speed of light, as if there were no limits on how fast they could keep accelerating. With an infinite supply of energy, they could travel the 4,3 light years in what they perceive to be 7 days, 7 hours, 7 minutes, or 7 seconds (let's ignore G-forces here, or how to have such vast quantities of energy at their disposal). The crew of a spacecraft experiences no "upper limit" to how fast the universe will allow them to traverse a distance.
What are you talking about? I just did "echo 1,2 > test.csv" then opened test.csv in OpenOffice Calc, then saved it as test2.csv from the save dialog. No complaints. Then I clicked to close it. No complaints about unsaved changes. Did you actually try that out before you commented? I don't have any of the other programs you mention on this computer, so I'll pick another - let's try OpenOffice Writer. Made a text file, opened it, saved it as a.txt file, it asked me for the encoding, I confirmed it, I clicked closed, and it closed without trying to force me to save as an.odt.
I'm sorry, but GIMP's change is totally broken behavior. The most common workflow for GIMP (as you can see from all of the rage on the forums when these changes occurred) is not long complex workflows, but simple changes to jpegs or pngs. Open, change it, save it, close it. What sort of moron do you take people for to think that you have to "protect" them from choosing a format of file that doesn't save layers, and instead try to make them always save whatever they do in a format that no other programs support? As if a dialog warning them that it doesn't save layers and asking them if they want to flatten it, like Gimp used to do, isn't enough? What on earth is the point of *banning* people from typing in a file with the suffix that they want to use in the save menu, and instead making them choose an entirely different menu? Actually two different menus, depending on context, only one of which has a keyboard shortcut. It's just ridiculous. We're not preschoolers, we don't need the hand-holding.
An interesting side effect of this would be that it would actually be theoretically possible to send a probe into a black hole and get a signal back from it. If you're REALLY, REALLY, REALLY patient, that is;)
(more realistically, one would likely try to probe the insides by making mciro black holes inside colliders and trying to get them to consume particles before they collapse, then looking for traces of information in the aftermath of the collapse)
And from the traveler's perspective the universe is consistent and there's no information loss either. They still see an apparent horizon, a place where time appears to stop, but they never reach it, it always recedes ahead of them. To them, the area beyond that apparent horizon is also not part of spacetime, but nothing ever manages to enter it so no information appears to be lost.
They of course eventually get ripped apart by tidal forces, but their information doesn't disappear into a "no-hair" singularity, it remains to be released when the black hole evaporates. As a black hole evaporates, time showing the particles falling deeper and deeper into it becomes observable to the outside world (albeit incredibly distorted and with the matter ripped to bits).
Again, that's at least my understanding of Hawking's "black holes don't actually exist" concept, and it makes logical sense to me. From the perspective of a traveler, they're just falling to their deaths in an extreme sort of collapsed star. From the perspective of an outside observer, they've fallen into a spot where a the collapsed star has ripped a hole in spacetime that won't start back up (from our perspective) until the "hole" boils off. Nothing ever lost, nothing ever undefined, always part of our universe, just effectively frozen temporarily in time. From our perspective.
Not only do they bundle it with adware, but they've apparently sabotaged GIMP too - for example, they apparently changed the save dialog so that you can only save XCF files and have to click through a "you have unsaved changes" warning when you export to a different format. They added an very difficult to precisely adjust sliders to things like brush size. They took out 16 bit color support. Basically, sourceforge has really totalled GIMP.;)
Yeah, because this is untimely, facturally inaccurate, five years old, and equivalent to a story about the sun being made of freshly chopped artichoke hearts? Meanwhile things like this and this are timely wellsprings of useful information?
And care to respond to the people mocking your "busy weekend" excuse, given that your weekend appears to be five days long and your "the main reason it's late" post which gives an entirely different reason for the delay?
No, from both perspectives it seems like the time of the other has slowed down, including Earth from the perspective of the ship.
This is not only incorrect, but impossible. If my time is speeding up and I'm looking at your watch, it's going to appear to be slowing down, and vice versa. Two parties both slowing down will appear indistinguishable from either party, rendering the concept of time dilation pointless.
The rest of what you wrote is what I wrote, just phrased differently: that from the perspective of the people on the ship, the 4,3 light year journey only takes 70 days. They are not capped in their rate of travel by some cosmic absolute "speed limit". Only to a third party to which they are moving relative will their velocity appear to be unable to reach or exceed c.
Numerous pages, including this one from NASA, say that from an outside perspective it takes an infinite length of time for an object to cross the event horizon. Here's an "Ask a Physicist" column about black holes that says that time distortion reaches infinity at the event horizon. The Wikipedia article on event horizons says the same thing.
From our perspective, nothing ever passes the event horizon and thus the information is never lost.
They sort of do, but they're so distorted from our perspective as to be unrecognizable. Matter entering a black hole appears progressively more stretched out across its event horizon and doppler shifted.
No, from an outside perspective it's never inside the event horizon. Only from the perspective of the matter entering the black hole does it cross. Saying "by then it's well within the event horizon" is simply not accurate from an outside perspective. No data collected from Earth will ever correspond to a reality in which the object has passed the event horizon.
Which is why there's no information paradox: the information is never in an unreachable state from any perspective.
Another one that I see a lot of people having trouble with: that of there being a universal speed limit. I'm surprised at how many people think this means there's a speed limit from all perspectives.
If we launch some incredible 100fold-staged antimatter spacecraft capable of reaching 0.999c toward Alpha Centauri 4,3 light years away, from the perspective of people on Earth, it'll never reach or exceed c and will take a touch over 4,3 years to get there. But from the perspective of people onboard the spacecraft, they're reaching their destination in only 70 days. From our perspective, their time slows down 22,4-fold; from theirs, Earth time has speed up. We see their velocity as capped off at c; to them, it's as if they can just keep accelerating without limit.
Now, it's not exactly like "going really fast"; everything around them seems pinched toward the forward direction and shifted to blue, like this - the same situation as where we see light emitted from particles moving at relativistic speeds relative to us (such as a black hole's event horizon) doppler shifted and distorted. If the occupants of our spacecraft go fast enough, even the cosmic microwave background will be shifted into the visible spectrum.;)
Slashdot Mirror
The more I read, the more it looks like it should be possible to "backport" birds to a surprising degree even without any unobtanium "dinosaur DNA". Even without studying what specific genes do, we can already start by comparing different lineages to see what genetic shifts in birds occurred between their theropod ancestors and modern descendents (for example, if most other groups of animals, including alligators, have a certain gene but birds don't, then that change occurred at some point on the bird side of the branching point between birds and alligators). Looking at modern descendents won't give us an exact picture of their common ancestors, but it'll certainly let us role back a lot of the changes. Combining that with reasoning out and experimenting with what morphological changes in birds that differ from dinosaurs are the result of what genes... we should be able to come up with something rather close to their ancestors at different stages.
It's amazing how much detail they're starting to be able to determine about ancient species - even to the point of being able to determine the number of wing quill feathers in velociraptors. We're certainly constraining the reversal problem more and more.
Oh god, I just had a terrifying thought... A T-Rex with the threat gestures of an Amazon. For those who don't own Amazon parrots, when they get overexcited or aggressive, they not only do this fantail display, but they have this creepy thing that they do with their eyes where they make their pupils expand and contract. Picture this, but with the pupil repeatedly changing in size 3x while it stares at you. It basically means "This is my Crazy Time. Go on, try coming close to me, see what happens!" They really lose their mind during it - for example, they may go into Crazy Mode because you gave them some treat that got them overexcited, but because they can't think straight, they're prone to drop and lose whatever it was that you gave them.
But yeah... crazy T-rex flaring whatever feathers it has and giving you an unflinching death stare with giant pulsating yellow eyes.
My parrot can take the backs off my earrings and take my earrings out without eating the backs or damaging my ears. He can open clasps on my clothes. No question that their beaks are dexterous.
However, I think the author was actually referring more to "adaptable". Bird beaks come in all sorts of shapes, apparently achieved by relatively simple genetic tweaks that allows them to adapt quickly (in evolutionary terms) to changing food sources.
Well.... any long-term confined high temperature isotropic quasi-neutral maxwellian plasma has to be large. Of course, if you start changing those requirements, you start changing the required size for your reactor. It's not theoretically impossible to have a viable fusion power plant that does not follow those constraints; the challenge is achieving it without either imposing a new, even more onerous series of challenges on yourself. Drop the concept of long-term confinement (for example, inertial confinement) and you find yourself with incredibly extreme compression challenges and having to deal with blowing your target apart on every fire. Don't use a quasi-neutral plasma and the plasma density drops by orders of magnitude, meaning your fusion rate drops so low that even little losses in the system will kill the concept. Don't use a maxwellian plasma and you have to find a way to hold the plasma away from thermalization without wasting more energy than the fusion yield, which is impossible by simply applying energy to part or all of the plasma - it's only even theoretically possible if you accelerate only the highest energy ions, creating a plasma only slightly skewed from a thermal distribution, and even if you have such a means, it's not easy. And so forth. You can remove constraints on fusion but then you get hit by others.
Unlike many here, I don't see it as an impossible problem simply because it hasn't been made economical yet despite decades of work. Because in those decades of work there's been orders of magnitude improvement, and I don't see those improvements just suddenly ceasing across every line of research. But no question, this is a Difficult Problem(TM).
No, I haven't submitted a paper on it. It's just a concept that I'm still working on at this point, and I want to have a proper simulation to back it up.
Oh, god, space technology is full of brilliant hacks. For example, New Horizons' radio. It has two amps connected to one dish, designed as a primary and a backup. But while it was en route, an engineer hit upon an idea to have them both transmit at the same time through the same dish, doubling the bandwidth. Normally that wouldn't make sense, except that the amplifiers have signals with different polarization, and these can be separated back out on Earth.
Great, except for one problem. The second radio was designed as a backup, they weren't planned for simultaneous operation - so there's not enough power to run them both and everything else at the same time. There's barely enough power to run just the radios - and I mean, it's not like you can just shut off the flight computer to free up more power. Well... actually, that's exactly what they do. When have a ton of data accumulated that they want to get to Earth and no critical science to do, they spin the craft up like a bullet to keep it stable and the dish pointing at Earth. Then they shut down the whole guidance and control system and pretty much everything else on the craft not essential for reading and transmitting data. It stays in this mode for days for a week or two, until all of the onboard data is transmitted, then they spin it back down so that they can do things like take pictures once again.
What sort of environmentalists have you been hanging around with? Environmentalist opposition to dams is so well known that "blowing up dams" is one of the cliche stereotypes of "eco-terrorists".
What on Earth are you talking about? Did the government foot the bill after the Deepwater Horizon incident? After any of the coal ash slurry failures? Of course not, the companies responsible did, and it cost them an utter fortune. The difference here is that unlike with nuclear power, their liability is uncapped. With nuclear power, the liability in the case of catastrope is a cost borne by taxpayers.
Which is why BP and the coal mining companies responsible are now bankrupt?
And FYI, industries carrying major risk are effectively required to have what amounts to insurance against those who go bankrupt. It's called Superfund, and it's supported by taxes on polluting industries - a "polluter pays" principle. Price-Anderson is based on a "public pays" principle. The money to cleanup in the event of a major nuclear disaster (over $12B) doesn't even come from a levy on the nuclear power industry. In fact, there is no money there for such a cleanup, the government is just supposed to come up with it if it happens. Fukushima for example is expected to cost over $100B in direct cleanup costs alone, let alone the much larger potential liability for claims.
Um, yes they are. You mention Deepwater Horizon. Are you unaware that it was insured, with liability coverage?
To wit, once again, the company didn't go bankrupt. They minimized the cost through a very effective legal campaign, of course. The government did not socialize the damages; it remained their responsibility to pay them. The fact that they managed to weasel out of having to pay a lot of what they should have paid doesn't change who the responsible party was. Nor does it make it logical that the solution to companies like Exxon weaseling out of payments is to have the government assume liability for major disasters and let those who caused them off the hook.
The Soviets were hardly unique in terms of bad reactor design. Have you seen the design used for the British Windscale plant? It makes you want to hit your head against a wall when you read it. They literally just stuck canisters of fuel into holes in the wall, hit them in by hand with ram rods, and hoped that the old canisters would fall out the back into a narrow trench of water. The designers got mad and nearly derailed it when one physicist wanted to put a really trivial pollution scrubber on the stack; they taunted him over it afterwards for wasting money. Now, saying "canisters" makes it sound fancier than they were, they were basically glorified aluminum cans full of highly flammable uranium, stuck into a hot reactor. Then they changed their fuel mix that they put inside without redoing any of the engineering. Including having them full of more flammable stuff like lithium and magnesium metal. And then they cut off the cooling fins from the canisters. Their monitoring was so poor that when the system inevitably caught fire they didn't notice it for days. They then went down there and started poking around in a hole with the ramrod; it came out covered in molten uranium.
Chernobyl was a paragon of safety compared to Windscale.
Yeah, it seems thorium has become the nuclear-reactor-hype of the day, the ShinyNewTech replacing PBMRs. The pattern repeats. I wish these people would at least google "ShinyNewTech disavantages" before spouting off about how ShinyNewTech is the savior of the world.
First off, who's extolling the virtues of hydroelectric dams? Dams usually fall on environmentalists' hate lists at around the same place as coal, give or take a few slots.
Extolling the virtues of wind or solar, yeah. But you better believe a wind farm operator will be sued if a turbine falls on someone's house, or a solar thermal plant if their mirrors misalign and blind a pilot. And for that matter, you better believe that a hydroelectric dam operator will be sued if their dam breaks (at least in the first world). And most companies willingly insure their large projects as a hedge against risk.
The aspect of Price-Anderson that people complain about is that the US government foots the bill for the vast majority of costs in the event of a catastrophic accident. The power plant operators only need to insure enough to foot the bill to insure against minor accidents, something most operators would want to do anyway to protect themselves. Many people find the capped liability to be a highly distorting influence on the market, socializing the risks while keeping the profits private.
Actually, no. But I'll be able to in the future if needed. :)
The waste issue (as well as inherent safety) is part of the reason that there's so much research on ADSRs right now (note: the article says that an ADSR "would use thorium as a fuel", but it's not actually limited to thorium, it can use any subcritical fissile core). Spallation can rip apart the long-lived actinides that don't have a sufficient (n, gamma) cross section to prevent their accumulation in nuclear waste. And of course, since the core is inherently subcritical by design, simply not enough neutronicity under any condition to sustain a chain reaction on its own, when you shut the beam off, fission ceases instantly (though you still have decay heat like with any other nuclear power plant). Spallation source provides no more than about 10% or so of the neutronicity, but it's the amount needed to push the core over the edge.
I have my own very radical variant on the concept of an accelerator driven fission that I'm working on simulating now in Geant4 (although that was probably a poor choice of software, apparently their thermal scattering codes are really immature... as far as CERN is concerned, once particles get down below the MeV range they're usually not particularly interesting). But anyway the concept is to have a core with literally zero neutronicty - a lithium-burning reactor. The basic concept is as such:
1. A planar proton beam is delivered by one or more high power linac beamlines. Commercial-scale linac costs - without any improvements in technology - are expected to cost $5-20 per watt. The particular design would call for very high voltage (~16MV) klystrons to drive it - and not simply to reduce size (more in this shortly)
2. The proton beam bombards a fragment emitting target inside an axial magnetic field in a vacuum. The estimation of deceleration efficiency is estimated at over 90% in fragment reactors due to the lack of Carnot losses (according to the published research on the subject). The resultant HVDC will be direct converted to the klystron voltage in producing the electron beam that drives the linac. About 60% of the energy of spallation goes into fragment production. Fragments will be drawn away from the fragment target en route to the collector via a slightly expanding axial magnetic field. Fragment collection allows for automatic isotope separation.
3. The maximum power output of a fragment reactor is limited by its surface area and its ability to radiate heat. Fragment-emitting targets can be either electrostatically suspended dust or rapidly rotating with thin fibers or planes of target material, in order to radiatively cool without melting. Spallation targets, for efficiency, need to be high-Z materials, such as lead, tungsten, mercury, etc. Tungsten is particularly attractive due to its high melting point of 3695K. High-Z metal-rich ceramics are also possible targets, with very high melting points. The temperature of the chamber's beryllium walls being radiated to will be around 1050K. This means heat exchange between a ~3000K emitter (4.6e7W/m) and a 1050K receiver (6.8e4W/m), or about 4.5MW per square meter. In short, this allows for a surprisingly compact core, limited more by the length necessary to ensure a sufficient proton spallation cross section.
4. Neutrons emitted by spallation (at a cost of 30-40 MeV per neutron) are heavily biased by
You can see the parameters, the cost of Price-Anderson covering them in the event of a catastrophic accident beyond the minimums is not covered.
Also, people should be careful not to confuse the prices on the calculator with the price of electricity that they pay. Power plant generation costs and consumer purchase rates are not the same thing. Industrial rates are at least closer to generation costs, but even they add a couple cents per kWh to the cost.
Not forever, as black holes don't last forever. They evaporate due to Hawking radiation.
This is ridiculous. Even "at the most superficial level introduction of relativity "you should know that if a person departs earth moving at "nearly C" and comes back, far less time will have past for them than someone who stayed on Earth the whole time.
First off, apart from trying to add confusion, why did you change the velocity from the one I gave? Secondly, from a trip travel time perspective, it doesn't matter whether you view it as time dilation or length contraction. The trip at 0.999c takes 70 days from the perspective of the crew. That's the beginning and end of it right there. From their perspective, it's as if they got there moving far faster than the speed of light, as if there were no limits on how fast they could keep accelerating. With an infinite supply of energy, they could travel the 4,3 light years in what they perceive to be 7 days, 7 hours, 7 minutes, or 7 seconds (let's ignore G-forces here, or how to have such vast quantities of energy at their disposal). The crew of a spacecraft experiences no "upper limit" to how fast the universe will allow them to traverse a distance.
What are you talking about? I just did "echo 1,2 > test.csv" then opened test.csv in OpenOffice Calc, then saved it as test2.csv from the save dialog. No complaints. Then I clicked to close it. No complaints about unsaved changes. Did you actually try that out before you commented? I don't have any of the other programs you mention on this computer, so I'll pick another - let's try OpenOffice Writer. Made a text file, opened it, saved it as a .txt file, it asked me for the encoding, I confirmed it, I clicked closed, and it closed without trying to force me to save as an .odt.
I'm sorry, but GIMP's change is totally broken behavior. The most common workflow for GIMP (as you can see from all of the rage on the forums when these changes occurred) is not long complex workflows, but simple changes to jpegs or pngs. Open, change it, save it, close it. What sort of moron do you take people for to think that you have to "protect" them from choosing a format of file that doesn't save layers, and instead try to make them always save whatever they do in a format that no other programs support? As if a dialog warning them that it doesn't save layers and asking them if they want to flatten it, like Gimp used to do, isn't enough? What on earth is the point of *banning* people from typing in a file with the suffix that they want to use in the save menu, and instead making them choose an entirely different menu? Actually two different menus, depending on context, only one of which has a keyboard shortcut. It's just ridiculous. We're not preschoolers, we don't need the hand-holding.
An interesting side effect of this would be that it would actually be theoretically possible to send a probe into a black hole and get a signal back from it. If you're REALLY, REALLY, REALLY patient, that is ;)
(more realistically, one would likely try to probe the insides by making mciro black holes inside colliders and trying to get them to consume particles before they collapse, then looking for traces of information in the aftermath of the collapse)
And from the traveler's perspective the universe is consistent and there's no information loss either. They still see an apparent horizon, a place where time appears to stop, but they never reach it, it always recedes ahead of them. To them, the area beyond that apparent horizon is also not part of spacetime, but nothing ever manages to enter it so no information appears to be lost.
They of course eventually get ripped apart by tidal forces, but their information doesn't disappear into a "no-hair" singularity, it remains to be released when the black hole evaporates. As a black hole evaporates, time showing the particles falling deeper and deeper into it becomes observable to the outside world (albeit incredibly distorted and with the matter ripped to bits).
Again, that's at least my understanding of Hawking's "black holes don't actually exist" concept, and it makes logical sense to me. From the perspective of a traveler, they're just falling to their deaths in an extreme sort of collapsed star. From the perspective of an outside observer, they've fallen into a spot where a the collapsed star has ripped a hole in spacetime that won't start back up (from our perspective) until the "hole" boils off. Nothing ever lost, nothing ever undefined, always part of our universe, just effectively frozen temporarily in time. From our perspective.
Not only do they bundle it with adware, but they've apparently sabotaged GIMP too - for example, they apparently changed the save dialog so that you can only save XCF files and have to click through a "you have unsaved changes" warning when you export to a different format. They added an very difficult to precisely adjust sliders to things like brush size. They took out 16 bit color support. Basically, sourceforge has really totalled GIMP. ;)
Yeah, because this is untimely, facturally inaccurate, five years old, and equivalent to a story about the sun being made of freshly chopped artichoke hearts? Meanwhile things like this and this are timely wellsprings of useful information?
And care to respond to the people mocking your "busy weekend" excuse, given that your weekend appears to be five days long and your "the main reason it's late" post which gives an entirely different reason for the delay?
This is not only incorrect, but impossible. If my time is speeding up and I'm looking at your watch, it's going to appear to be slowing down, and vice versa. Two parties both slowing down will appear indistinguishable from either party, rendering the concept of time dilation pointless.
The rest of what you wrote is what I wrote, just phrased differently: that from the perspective of the people on the ship, the 4,3 light year journey only takes 70 days. They are not capped in their rate of travel by some cosmic absolute "speed limit". Only to a third party to which they are moving relative will their velocity appear to be unable to reach or exceed c.
Numerous pages, including this one from NASA, say that from an outside perspective it takes an infinite length of time for an object to cross the event horizon. Here's an "Ask a Physicist" column about black holes that says that time distortion reaches infinity at the event horizon. The Wikipedia article on event horizons says the same thing.
From our perspective, nothing ever passes the event horizon and thus the information is never lost.
They sort of do, but they're so distorted from our perspective as to be unrecognizable. Matter entering a black hole appears progressively more stretched out across its event horizon and doppler shifted.
No, from an outside perspective it's never inside the event horizon. Only from the perspective of the matter entering the black hole does it cross. Saying "by then it's well within the event horizon" is simply not accurate from an outside perspective. No data collected from Earth will ever correspond to a reality in which the object has passed the event horizon.
Which is why there's no information paradox: the information is never in an unreachable state from any perspective.
Another one that I see a lot of people having trouble with: that of there being a universal speed limit. I'm surprised at how many people think this means there's a speed limit from all perspectives.
If we launch some incredible 100fold-staged antimatter spacecraft capable of reaching 0.999c toward Alpha Centauri 4,3 light years away, from the perspective of people on Earth, it'll never reach or exceed c and will take a touch over 4,3 years to get there. But from the perspective of people onboard the spacecraft, they're reaching their destination in only 70 days. From our perspective, their time slows down 22,4-fold; from theirs, Earth time has speed up. We see their velocity as capped off at c; to them, it's as if they can just keep accelerating without limit.
Now, it's not exactly like "going really fast"; everything around them seems pinched toward the forward direction and shifted to blue, like this - the same situation as where we see light emitted from particles moving at relativistic speeds relative to us (such as a black hole's event horizon) doppler shifted and distorted. If the occupants of our spacecraft go fast enough, even the cosmic microwave background will be shifted into the visible spectrum. ;)