Abortion does not occur frequently enough to put a serious dent in the birth rate. There would have to be millions of abortions each year and there are only (serious hand-waving here) a few tens of thousands performed each year.
The abortion rate in the United States has run up to about 1.5 million a year. It's currently running something above 1 million a year. Which is not to say that birth rates would change horribly if it was unavailable, since people would be more careful; however, there would be a lot of misery involved, since many of the people having the unplanned and unwanted babies would oftimes be the those least able to do a good job of raising them. --
Large families are a neccessity in rural/tribal agrarian societies where there is a lot of physical labor to be done and a high rate of mortality.
That's incomplete. To be more accurate, large families are an advantage anywhere that children are economic assets. It doesn't matter how high the mortality is; people usually respond to their own economic interests, with a depressing emphasis on the short term. Immediate incentives rule, and welfare statism is the prime culprit.
One huge and very un-publicized reason for this is the rise of government-funded retirement programs. The laws governing FICA/ERISA had a lot of thought put into them, but they goofed horribly in ignoring crucial issues such as:
Intelligent responses to changes in life expectancy; a pay-as-you-go program can't have the same tax rate and retirement benefits for a population with a life expectancy of 85 as for a population with a life expectancy of 65. This is a no-brainer.
Responses to changing demographics, ditto.
Last and most important: the influence of government-guaranteed retirement on the need to have children as a guarantee of support in old age.
That last one is the killer. Thanks to the government taxing other people's kids to support a nation-wide retirement program, you don't need to have any of your own! You can enjoy the same benefits as the people who worked to raise a productive family and incur none of the costs; you even benefit, because you can work more and raise your retirement payouts with your increased lifetime average income. Couples by the millions have responded to this incentive and have foregone having children, but still expect to get that Social Security check every month. It's no mystery that the biggest drop in fertility rates has been in the European states with their rather generous social policies.
The simple fact of the matter is that we've got to have more than just money to make the system work. We have to have people. And not just any people either; they have to be educated and motivated. Half-literate immigrants from small villages can pick our crops, but they won't become the medical specialists needed by an aging population. They won't be the engineers to design their products, and they won't be the teachers and professors to educate the generation to follow. And we can't continue to brain-drain the world; aside from the likely revolt of imported labor under punitive taxes to support our aging native population, we should be doing this ourselves.
There's a rather simple management principle that needs to be applied here: what gets rewarded, gets done. If we are going to stabilize our situation and actually have the workers to keep things going in 20 years, we are going to have to provide both short-term and long-term rewards to the people who make it happen. This means giving parents retirement bonuses based on the productivity of their children (and their spouses if married), and immediate benefits for raising kids who are educated instead of social problems.
If the middle-class and poor folks could shave a couple points off their tax rate because their kids were doing well in reading and math, do you think they'd have such a disinterest in the performance of their local schools? They'll hang incompetent educators from the playground swings if it means something that personal. They'll read to their kids and help with their homework. If they're the victims of bad schools, they might even start studying this material themselves so they can make sure their kids can do it (better to have an educated public and electorate late than never, eh?). Reward it, and it'll get done. --
AM sidebands with a second channel, thereby allowing stereo reception, but this has never happened.
Actually, it's been done and I've heard it broadcast.My last car had an AM-stereo-capable radio.
Why bother with improving AM, when FM is better anyway? Simply reallocate the AM band for FM use and get one kind of radio for everything.
Because an FM radio channel is 200 KHz wide and an AM radio channel is 20 KHz wide (but often allocated on even finer boundaries, e.g. 10 KHz).You could get all of 5 FM broadcast channels into the entire AM band (550 KHz to 1610 KHz).There is also the little issue of the 2 orders of magnitude difference in frequency between the AM and FM broadcast bands which complicates important details like receiver design.An AM/FM radio is really 2 separate receivers between the antenna connector and the audio amplifier. --
A device to warn cars of ice on a bridge would broadcast a low-power signal that would only reach cars at a distance of, say, 500 feet.
Exactly. And you can do that in the 300 MHz band currently allocated to keychain alarm transmitters.(I should know, I've done it.)There's no need for additional bandwidth.
This extra spectrum is for purposes above and beyond the useful little things like that.Do not make the mistake of believing that the explanation for this action is the same as the reason for it. --
That's what this amounts to. It would be trivial to piggy-back traffic information and other useful data on existing services, such as FM radio broadcast subcarriers. (What car ships today without an AM/FM radio as standard equipment?) We already have digital cellular service for moving data on behalf of the occupants of the car. So what's there in the car itself which creates the need for this new spectrum?
It seems pretty simple to me: Tracking vehicles. Not just tens or hundreds, but millions simultaneously. Oh, it'll be dressed up with some noble language like "It can help the tow truck find you when you break down" or "It can direct you away from traffic jams", but none of these things require the vehicle to broadcast data (and with the mandatory cellular location features, its position) all the time.
If you travel by bus or airline, your movements are easily tracked. Now we're looking at this being true for personal automobile travel as well. Surveillance society, here we come. --
Actually, now that you mention it, I have actually seen something close to the Dilbert Principle in action. Last year, my boss quit. His replacement was drawn from the ranks of the people who used to work for him; he also happened to be the only person who applied for the job.
This guy had been barely competent as an engineer; when his application needed a timer, he was not even capable of looking at the block diagram of his chip affixed to his own wall and say "Wow, there's no timer block on any of the busses going to the CPU core!" And he was the guy who was promoted to be my boss. He succeeded in cutting me off at the knees when we needed to present a united front to a supplier who was intent on screwing us. It wasn't like I needed another reason to move on, but that helped.;-)
I have no idea if he would have received the job if there had been other applicants, but the fact that he was given the job rather than a search going for applicants from the outside says something about the organization (a Fortune 50 company, FWIW). --
If you cared to look back into pre-Web publications, you'd find that this was enshrined quite some time before as the Peter Principle: "A person tends to be promoted up to their level of incompetence." --
I once had the experience of listening to the radio and hearing about a mid-air collision between a Piper aircraft (a Cherokee, I think) and a "Beechnut" Aerostar. They repeated "Beechnut" over several hourly news updates.
This struck me as hilarious, and embarrassing. Beechnut makes baby food; Beechcraft once built light airplanes, but they never built Aerostars AFAIK. The Aerostar design was then owned by... Piper!
After listening to this for a while, I finally phoned the radio station and told them that the Aerostar had been most recently built by Piper. They corrected their copy in the very next hour's coverage. So I made a small difference in the quality of news coverage that day, and perhaps kept some people from getting the impression that baby food was the latest hazard to air travel.
The Jane's episode is the next level, getting the facts right before going to press. We have all seen just how bad journalism can get, when writers try to inform the public on subjects they understand only too poorly themselves. It's not a moment too soon. -- Deja Moo: The feeling that
Both I and others have made this point before, but I'll make it again:
Most cable installations were created, and paid for, under a grant of an exclusive franchise. This is an inherently anti-competitive situation, and it should not be allowed to continue.
Cable companies are infamous for acts such as getting rid of the channel you want and substituting something you have no use for, and accepting "deals" from content suppliers which require them to carry several channels of crap so they can get one popular one. Now these cable companies are suddenly in the ISP business. What does this mean for the customers?
Since the cable company has an exclusive on the local broadband market, the customer can expect to see useless "services" layered into their bill.
Access to other ISP's will be slower and/or more difficult.
Should the phone company roll out xDSL, these mega-companies can be expected to behave like the airlines: when one of them adds a "service" or raises prices, the other will too. Customer choice will all but vanish.
The FCC should have bitten the bullet and kicked the cable companies (and the phone companies) out of the content business. Entities which supply bandwidth should not be able to tie that product to a particular brand of content; the customer should be able to go anywhere for pay content, or forego it entirely and only visit free sites. The only thing the monopoly cable/phone companies should be allowed to do is move data; everything else should be the province of independent, free-market suppliers. -- Deja Moo: The feeling that
After taking a few more factors into account, I have to agree with you. For instance: sonic speed limits of infalling material. Assuming that the speed of sound is 10 km/sec and the Kerr radius is 2 um (about a 1e-4 M-E mass), the volume falling into the BH would be 4/3 * pi * 8e-18 * 1e4 = ~3e-13 m^3/sec. That is perhaps 3e-9 kg/sec. Heating of the infalling material would reduce the accretion rate further, since the density falls faster than the speed of sound rises. I know I'm not taking degeneracy of highly compressed matter into account, but it would take a lot more than that to speed things up to a progression in less than millions of years.
As for the "seething ball of iron silicate" scenario, if energy could be transferred outward fast enough (say, from convection outside of the radiative zone) this would be possible, but you appear correct that this requires a rate of heat generation too high for a mini-BH to manage by accretion. Even if all of 3e-9 kg/sec was converted to energy, this would only yield 2.7e10 watts, or about the solar energy falling on 20 km^2 of the top of the atmosphere. A trifling amount. Next mystery: What would a decaying mini-BH (say, 1 million tons) do if it happened to be inside a planet when it went boom?
That was educational. Pitcher of Heineken? -- Deja Moo: The feeling that
Of course, my Dad and Mom hated the energy ant... because they were convinced it was Jimmy Carter's fault that everyone was waiting in gas lines.
They were correct: it was Carter's fault! Carter decided to ration gasoline to particular areas instead of shipping to places which were low and letting prices fall where they may. This led to huge gas lines in the places where his allocations were short, and areas not far away where both gas stations and motorists had full tanks.
This short-signed (ab)use of executive power led to enormous wastes of people's time, energy and fuel (yes, fuel, wasted idling in gas lines waiting to get gas). This was worse than anything Clinton is accused of doing, and I think it's a shame that nobody tried impeaching the ol' Peanut Farmer over it. -- Deja Moo: The feeling that
Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C.
Yes. It would get up to about 120 km/sec on the basis of its gravitational potential. It would only get to a large fraction of c within a few hundred meters of the BH. More to the point, an object on the equator moving tangentially at 1600 kph and allowed to ride inward on the surface of a frictionless sphere toward a point mass of 1 M-E (losing energy but maintaining a constant angular momentum) would achieve orbital velocity of about 30 km/sec when it had fallen to about 100 km radius. Anything inside this radius would have to fall even further, or get angular momentum and energy from somewhere else, to avoid being pulled (or pushed) even further inward. -- Deja Moo: The feeling that
Since you are under the impression that you've provided a counter-calculation, but you haven't produced anything resembling one and have missed the point in several other areas, I think you might have had too many beers already. You began celebrating just a wee bit too soon.
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
How can you "eat zeroes" without calculating? Bah.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
..assuming the black hole already contains the earth mass, which is not the case. My point is that since it begins small, in a dusty rotating environment, the black hole will end up with only a small fraction of the mass.
No, it would begin small, in the middle of a rather dense planet. As soon as it got as big as the distance between atoms in the core, matter would begin falling into it at the speed of sound. So long as it sat at the middle of a large semi-liquid mass, nothing would stop it from growing. The only way for it to stop growing would be for the remaining mass to be either
spun up from the contraction of its radius so that it achieves orbit, or
blown off into a jet.
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
It'll find its way by gravitational attraction, and again you miss the point. It doesn't matter how many Schwarzchild radii that is; absolutely nothing on Earth could achieve an orbit farther out than that on its own angular momentum, so everything else would either be pushed into the BH by the pressure of the matter above it or blown off in one of the jets.
About the best an object anywhere on the surface of Earth could do is to find an orbit at about 1/64 of its original radius (and that's the best). Since the volume of a sphere scales as r^3, chopping the radius of a sphere by 63/64 eliminates 262143/262144 of its volume. That's about 99.9996%.
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998%;-p). You seem to calculate from an existing M-earth BH.
I made no such assumption. I assumed only that any BH created at rest with respect to the surface of the earth would fall inward, and everywhere it went it would have plenty of matter to eat. As for the centrifugal potential, it would only make a difference if the angular momentum could not be dissipated against the matter further above. As angular momentum and energy are lost to friction, the matter spirals in.
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
I have no idea. I've lost the equation for the evaporation rate of a BH, and since the Hawking radiation would tend to push things away the calculation is too complex for a simple discussion like this one. Now, if I were going for my PhD in physics I might do it as part of my thesis project, but I'm not.
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
There's your error. You are assuming the matter is accreting from a thin disk (which is already in orbit). This assumption is not valid; it would be accreting from a nice, fat, spherical planet with a core of iron atoms at perhaps 10 grams/cc. To get to the thin-disk case, most of the planet would have to be either sucked down the BH or blown off in jets. Transfer of angular momentum outward works to give the remaining matter orbital velocity at a greater radius. It doesn't matter how small the Kerr radius is as long as there is a huge quantity of matter under pressure squeezing itself into the BH like water through a faucet.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).;-)
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor. The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years.;-) -- Deja Moo: The feeling that
Children should be taught to respect good laws, how to fight bad ones and most importantly the critical thinking process that allows them to determine for themselves, based on their own set of values, which are which.
The older I get the more I realize that it is pretty rare for a child to have the kind of vision that lets them see the ramifications of these decisions. This usually requires experience to develop, and experience takes time. The critical thinking and moral grounding is crucial, but it is not sufficient. -- Deja Moo: The feeling that
I resent it as well, everyone resents it. But that type of "the taxpayers foot the bill, therefore it's everyone's business" argument is horrifying to me because it's on the road to censorship and authoritarianism.
I think we can agree that there is a very real and substantive difference between a birth defect and an offense to someone's religious sensibilities.At least, I hope we can agree about it.Besides, the use of some taxpayer money for something that offends Catholics does not make things unfair, so long as the Catholics have their chance to see some money go to something that pleases them while offending, say, Hindus or atheists.
Sick, crippled babies are rather different.We can all agree that anything that leads to this outcome is bad. What we can't agree on is what we should do (besides things like changing the USDA guidelines for vitamin enrichment of certain foods).
That's exactly the language that was employed against the artists in NYC- that Catholics pay taxes, and therefore the art that was offensive to Catholics should be censored.
Or maybe that the taxpayers shouldn't be subsidizing art.And maybe the taxpayers shouldn't be subsidizing neonatal ICU's; perhaps the decision to try to save the extreme cases (or not) should be made by the parents when they select their insurance carrier, and the costs of the intervention passed to them in their premiums.It seems more fair to let people decide that their money is better spent on other things, and live with the consequences of their choices. -- Deja Moo: The feeling that
If I am correctly summing up what my nurse friends tell me, these babies' bills almost always go well beyond what the parents' insurance will cover (which is zero for the uninsured).The balance is paid by Medicaid; in other words, the taxpayers.
This means that all the parents who bring damaged children into the world because they decided to drink, or smoke, or ignore pre-natal care, or just eat all wrong (folate deficiency apparently causes the majority of neural-tube defects like spina bifida) are sticking the rest of us with the bill.And yes, I resent it. -- Deja Moo: The feeling that
DC-X just used old rockets, same as all other american space vehicles.
And that's because DC-X was an atmospheric test vehicle, designed and constructed specifically to prove some of the tricker parts of the DC-1 design (namely, the "flip over" transition from nose-first gliding flight to tail-first powered flight for landing). It used off-the-shelf RL-10 motors because developing new motors was not necessary and thus not part of the charter. Either DC-Y or DC-1 could have switched to an aerospike motor without changing the basic design.
The only advantage it had was it could take of and land vertically and move sideways - I dread to think of the fuel cost involved.
The fuel cost wasn't very much; the vehicle would have been mostly empty tanks by the time it landed. And it had other, very substantial advantages:
It did not have to glide to a landing. This allows considerably more flexibility in the aerodynamics.
It did not have to land horizontally. This is advantageous in two ways:
There is no requirement to transition from powered flight to gliding flight in order to land; the spacecraft always lands under power, so it can make an emergency landing as soon as it gets rid of enough fuel to avoid collapsing the gear.
Any flat patch of ground will do for an emergency landing site; no runway is required.
About the only thing the X-33 has going for it is that it behaves more like the Space Scuttle. Unfortunately, this similarity also appears to include development cost and schedule.
X-33 uses new engines, new materials, etc. Yes it takes longer to develop, yes it cost more and YES it is worth it.
Our current engines appear to be sufficient to build a much cheaper replacement for the Scuttle, and on a much faster schedule than X-33. In the mean time we are stuck with a vehicle designed in the 70's whose performance is a fraction of what was promised (65,000 lbs to orbit is only a dream) and requires a standing army of over 10,000 maintenance personnel to keep it flying. Worse, we cannot build any more and if we lose even one vehicle it will force other programs (like ISS) to be radically scaled back or even scrapped. Last, the engine technology of X-33 could be applied to a VTVL with little difficulty; however, with a going DC-1 program it would be forced to prove its worth instead of being locked in as part of "the only game in town". You can't escape the conclusion that the X-33 program is more about generating lots of money for contractors than making a cost-effective launch vehicle. -- Deja Moo: The feeling that
Sorry, I thought you might be getting a couple concepts mixed. As for commercial aircraft, you're right:many of them already require more space to land than to take off so it's doubtful that saving them 35 seconds or so of acceleration would be worth the cost of adding catapult gear to either the airports or airplanes. -- Deja Moo: The feeling that
i doubt enough jet fuel would be saved in the short distance of a runway to offset the cost of the whole system...
With a 600 MPH boost, the rocket can cut off its engines with 600 MPH less of delta-V. It can also save on "gravity losses" because it could start with a faster climb and start flying horizontally sooner.
This wouldn't be useful on something like the Space Scuttle (pun intended) because the stack cannot handle 6 G's. Something like a re-designed X-33 (Venture Star) could do it. And I suspect that NASA is suggesting it now because the X-33's design compromises have added so much weight that it can't carry a payload to orbit without several hundred MPH of head start.
Somebody, Congress, please boot the idiot NASA managers who selected the X-33 proposal and hire the guys who designed the DC-X; if we'd just continued with the DC-Y we'd have an orbital test vehicle by now! Oh, I forgot, the program was too cheap and didn't have enough slush to generate your campaign donations! Silly me! -- Deja Moo: The feeling that
This concept is very old. It goes back beyond the British HOTOL aerospaceplane and all the way back to the Antipodal Bomber concept of Werner Von Braun in the 40's. Attributing it to NASA today just shows how backwards NASA is, and how clueless journalists are.
Sewing machines and electric drills do not use induction motors. They use universal motors. Completely different technology. Again, clueless journalists.
I could go on, but it's late, I'm tired... -- Deja Moo: The feeling that
While skin color and speech are patently obvious to anyone who can see and hear, how do you find out about someone's genes without taking a sample and doing a test? And without the knowledge of a person's genes, how can you use that to discriminate against them? If it is unlawful to perform the test, it's awfully hard to discriminate and not risk the penalties. -- Deja Moo: The feeling that
.. but not for artificial satellites;-p. Hokay the numbers are huge, I agree. But anisotropy does much more than dividing the radiation number by x. Besides that there are several important complications to your lucent but very crude calculations.
If you want to have a calculating battle, by all means jump in. I'm willing to fire off numbers at you and take your return fire, winner to collect a pitcher of beer from the loser if they should ever be in the same city. I admit that this wouldn't be much of a prize for you since I am not likely to visit the Netherlands soon and American beer being as lousy as it is, but I can't think of another prize worthy of a friendly competition.
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules.
- since most matter falling into the black hole is cold and already very deep in the potential well conversion effeciency will very much lower than the theoretically infinite distance approach
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
- all the mass surrounding the earth center carries angular momentum, the accretion disk into which the earth will transform will only on convert some small fraction of the potential energy of the accreting mass. Besides in our scenario we assume the mini black hole to originate at the earth's surface further decreasing the accretion rate and conversion efficiency. We are not talking about a hardly rotating collapsing stellar iron core here...
Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not), and as it absorbed mass it would also absorb the momentum of that mass. Unless there is a transfer of momentum, the center of mass of the system would remain on the same path. This means that the mini-BH would very quickly wind up stationary at the center of the Earth.
Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
- the black hole might starve before it can eat all of its food. After accretion disk forming only the inner 3*R(schwarzschild) orbits are unstable. Then angular momentum transport in the accretion disk will dictate the rate of energy production.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit. Without that, the inward pressure of the falling mass would only be balanced by radiation pressure from the accretion disk. Since an object on the equator only has the angular momentum to maintain a circular orbit at 1/64 of an Earth radius, at least 99.9996% of the Earth would be able to fall into the BH unless prevented by other mechanisms.
- much of the available gravitional energy will be converted into kinetic energy blowing a significant portion of the mass away in opposite jets
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
- the evaporated mass of the earth will consist of small iron and silicate particles creating a broad inpenetratable dust band on the equator just as seen AGNs. Given the available Si/Fe mass and high density you may happily assume that.01% of your overstimated radiation at the equator might be several orders of magnitude too high. Silicate grains are magnificent UV absorbers, and UV-soft Xray will be the major emission waveband in the accretion disk.
See my previous comment about scattering efficiency and losses.
My conclusion is that the earth satellites probably wont survive, but the Moon and Mars will laugh at Earth's misery. Especially since the momentum carried by the rest radiation will be ridiculously small compared to their orbital momentum.
I didn't say that Mars would be knocked out of orbit, I implied that the side facing Earth would be pretty thoroughly fried (a megaton/m^2 will do that). I'm pretty certain now that both Mars and Venus would lose their atmospheres (maybe only half of Venus, if the event went quickly).
Were it possible for this to happen, the Solar system would not be a healthy place to be that day. It would be best to be somewhere far away on vacation, and deal with the insurance agent upon your return. And hope you have a "full replacement planet" policy.;-) -- Deja Moo: The feeling that
There's also the small matter of the likely high correlation between intelligence and insanity. Remember the "Eve" episode of the X-Files?
After seeing utterly ridiculous plot devices in the only two episodes of X Files I've ever seen, I would never watch it again nor use it as an example of anything in the real world.
This holds fairly true in my own life... some of the most brilliant people I know are also some of the least able to deal with reality. One friend of mine got a 750 on themath section of the SAT at the age of 12, failed out of engineering school and is now working at KFC.
How much of that is natural, and how much is stress burnout from being a misfit? Reality is defined by the average. People who are misfits in some situations suddenly shine when they get into a group where people understand them and can interact on their level. If the average level of intelligence, for example, goes way up, then the super-intelligent won't be such outliers and will fit in a lot better. Without the stress you'd expect fewer burnouts. (And maybe we can engineer against stress, while we're at it.)
I know we can't be sure which of these scenarios (if either) is correct, but it'll be awfully hard to find out except by running the experiment. -- Deja Moo: The feeling that
Because we're offering an unfair advantage to those whose parents had money.
Children of parents with money have unfair advantages to get into Harvard and Yale today, and that is actually a bigger problem than anything that genetic engineering will cause.
Genetic engineering isn't like a prep-school education. It's a technical practice and lends itself to automation. You can expect the price to come down very rapidly with time, like gene-sequencing and computers. Ten years after the rich start using it, it'll be a middle-class thing. Ten years after that, everyone will use it if they can benefit from it.
And what will people use it for? I can see some working to keep some of the "disadvantageous" traits of their ancestors, but escape the consequences. For instance, modify the sickle-cell anemia gene so that homozygote embryos fail to develop. This keeps the heterozygote resistance to malaria but avoids the health impact of a child getting one gene too many. Sure wouldn't hurt! -- Deja Moo: The feeling that
The thing that a lot of posters in threads like this forget (on purpose?) is that this technology, like any other, is not in the hands of the state here. It is in the hands of parents-to-be. People select their kids' genes all the time. They do it mostly by mate selection and a few by sperm/egg donor, but everyone does it nevertheless. All the gene manipulators will do is expand the pool of choices. The dystopian aspects of GATTACA are due to an entirely separate possibility, and that is genetic discrimination; it's distinct from the ability to engineer genes. If we can outlaw discrimination on the basis of skin color and go as far as we have towards eradicating it, we can almost certainly keep discrimination on the basis of genes from going very far.
So what are we achieving here with gene selection for our kids? I think that what we're buying is health and vigor, and happiness to the extent that healthy and vigorous people are happier than those who are not. How can this be a bad thing? -- Deja Moo: The feeling that
Slashdot Mirror
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One huge and very un-publicized reason for this is the rise of government-funded retirement programs. The laws governing FICA/ERISA had a lot of thought put into them, but they goofed horribly in ignoring crucial issues such as:
- Intelligent responses to changes in life expectancy; a pay-as-you-go program can't have the same tax rate and retirement benefits for a population with a life expectancy of 85 as for a population with a life expectancy of 65. This is a no-brainer.
- Responses to changing demographics, ditto.
- Last and most important: the influence of government-guaranteed retirement on the need to have children as a guarantee of support in old age.
That last one is the killer. Thanks to the government taxing other people's kids to support a nation-wide retirement program, you don't need to have any of your own! You can enjoy the same benefits as the people who worked to raise a productive family and incur none of the costs; you even benefit, because you can work more and raise your retirement payouts with your increased lifetime average income. Couples by the millions have responded to this incentive and have foregone having children, but still expect to get that Social Security check every month. It's no mystery that the biggest drop in fertility rates has been in the European states with their rather generous social policies.The simple fact of the matter is that we've got to have more than just money to make the system work. We have to have people. And not just any people either; they have to be educated and motivated. Half-literate immigrants from small villages can pick our crops, but they won't become the medical specialists needed by an aging population. They won't be the engineers to design their products, and they won't be the teachers and professors to educate the generation to follow. And we can't continue to brain-drain the world; aside from the likely revolt of imported labor under punitive taxes to support our aging native population, we should be doing this ourselves.
There's a rather simple management principle that needs to be applied here: what gets rewarded, gets done. If we are going to stabilize our situation and actually have the workers to keep things going in 20 years, we are going to have to provide both short-term and long-term rewards to the people who make it happen. This means giving parents retirement bonuses based on the productivity of their children (and their spouses if married), and immediate benefits for raising kids who are educated instead of social problems.
If the middle-class and poor folks could shave a couple points off their tax rate because their kids were doing well in reading and math, do you think they'd have such a disinterest in the performance of their local schools? They'll hang incompetent educators from the playground swings if it means something that personal. They'll read to their kids and help with their homework. If they're the victims of bad schools, they might even start studying this material themselves so they can make sure their kids can do it (better to have an educated public and electorate late than never, eh?). Reward it, and it'll get done.
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This extra spectrum is for purposes above and beyond the useful little things like that.Do not make the mistake of believing that the explanation for this action is the same as the reason for it.
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It seems pretty simple to me: Tracking vehicles. Not just tens or hundreds, but millions simultaneously. Oh, it'll be dressed up with some noble language like "It can help the tow truck find you when you break down" or "It can direct you away from traffic jams", but none of these things require the vehicle to broadcast data (and with the mandatory cellular location features, its position) all the time.
If you travel by bus or airline, your movements are easily tracked. Now we're looking at this being true for personal automobile travel as well. Surveillance society, here we come.
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This guy had been barely competent as an engineer; when his application needed a timer, he was not even capable of looking at the block diagram of his chip affixed to his own wall and say "Wow, there's no timer block on any of the busses going to the CPU core!" And he was the guy who was promoted to be my boss. He succeeded in cutting me off at the knees when we needed to present a united front to a supplier who was intent on screwing us. It wasn't like I needed another reason to move on, but that helped. ;-)
I have no idea if he would have received the job if there had been other applicants, but the fact that he was given the job rather than a search going for applicants from the outside says something about the organization (a Fortune 50 company, FWIW).
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If you cared to look back into pre-Web publications, you'd find that this was enshrined quite some time before as the Peter Principle: "A person tends to be promoted up to their level of incompetence."
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This struck me as hilarious, and embarrassing. Beechnut makes baby food; Beechcraft once built light airplanes, but they never built Aerostars AFAIK. The Aerostar design was then owned by... Piper!
After listening to this for a while, I finally phoned the radio station and told them that the Aerostar had been most recently built by Piper. They corrected their copy in the very next hour's coverage. So I made a small difference in the quality of news coverage that day, and perhaps kept some people from getting the impression that baby food was the latest hazard to air travel.
The Jane's episode is the next level, getting the facts right before going to press. We have all seen just how bad journalism can get, when writers try to inform the public on subjects they understand only too poorly themselves. It's not a moment too soon.
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Deja Moo: The feeling that
- Since the cable company has an exclusive on the local broadband market, the customer can expect to see useless "services" layered into their bill.
- Access to other ISP's will be slower and/or more difficult.
- Should the phone company roll out xDSL, these mega-companies can be expected to behave like the airlines: when one of them adds a "service" or raises prices, the other will too. Customer choice will all but vanish.
The FCC should have bitten the bullet and kicked the cable companies (and the phone companies) out of the content business. Entities which supply bandwidth should not be able to tie that product to a particular brand of content; the customer should be able to go anywhere for pay content, or forego it entirely and only visit free sites. The only thing the monopoly cable/phone companies should be allowed to do is move data; everything else should be the province of independent, free-market suppliers.--
Deja Moo: The feeling that
As for the "seething ball of iron silicate" scenario, if energy could be transferred outward fast enough (say, from convection outside of the radiative zone) this would be possible, but you appear correct that this requires a rate of heat generation too high for a mini-BH to manage by accretion. Even if all of 3e-9 kg/sec was converted to energy, this would only yield 2.7e10 watts, or about the solar energy falling on 20 km^2 of the top of the atmosphere. A trifling amount. Next mystery: What would a decaying mini-BH (say, 1 million tons) do if it happened to be inside a planet when it went boom?
That was educational. Pitcher of Heineken?
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Deja Moo: The feeling that
This short-signed (ab)use of executive power led to enormous wastes of people's time, energy and fuel (yes, fuel, wasted idling in gas lines waiting to get gas). This was worse than anything Clinton is accused of doing, and I think it's a shame that nobody tried impeaching the ol' Peanut Farmer over it.
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Deja Moo: The feeling that
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Deja Moo: The feeling that
- spun up from the contraction of its radius so that it achieves orbit, or
- blown off into a jet.
It'll find its way by gravitational attraction, and again you miss the point. It doesn't matter how many Schwarzchild radii that is; absolutely nothing on Earth could achieve an orbit farther out than that on its own angular momentum, so everything else would either be pushed into the BH by the pressure of the matter above it or blown off in one of the jets.About the best an object anywhere on the surface of Earth could do is to find an orbit at about 1/64 of its original radius (and that's the best). Since the volume of a sphere scales as r^3, chopping the radius of a sphere by 63/64 eliminates 262143/262144 of its volume. That's about 99.9996%.
I made no such assumption. I assumed only that any BH created at rest with respect to the surface of the earth would fall inward, and everywhere it went it would have plenty of matter to eat. As for the centrifugal potential, it would only make a difference if the angular momentum could not be dissipated against the matter further above. As angular momentum and energy are lost to friction, the matter spirals in. I have no idea. I've lost the equation for the evaporation rate of a BH, and since the Hawking radiation would tend to push things away the calculation is too complex for a simple discussion like this one. Now, if I were going for my PhD in physics I might do it as part of my thesis project, but I'm not. There's your error. You are assuming the matter is accreting from a thin disk (which is already in orbit). This assumption is not valid; it would be accreting from a nice, fat, spherical planet with a core of iron atoms at perhaps 10 grams/cc. To get to the thin-disk case, most of the planet would have to be either sucked down the BH or blown off in jets. Transfer of angular momentum outward works to give the remaining matter orbital velocity at a greater radius. It doesn't matter how small the Kerr radius is as long as there is a huge quantity of matter under pressure squeezing itself into the BH like water through a faucet. Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor. The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years. ;-)
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Deja Moo: The feeling that
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Deja Moo: The feeling that
Sick, crippled babies are rather different.We can all agree that anything that leads to this outcome is bad. What we can't agree on is what we should do (besides things like changing the USDA guidelines for vitamin enrichment of certain foods).
Or maybe that the taxpayers shouldn't be subsidizing art.And maybe the taxpayers shouldn't be subsidizing neonatal ICU's; perhaps the decision to try to save the extreme cases (or not) should be made by the parents when they select their insurance carrier, and the costs of the intervention passed to them in their premiums.It seems more fair to let people decide that their money is better spent on other things, and live with the consequences of their choices.--
Deja Moo: The feeling that
This means that all the parents who bring damaged children into the world because they decided to drink, or smoke, or ignore pre-natal care, or just eat all wrong (folate deficiency apparently causes the majority of neural-tube defects like spina bifida) are sticking the rest of us with the bill.And yes, I resent it.
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Deja Moo: The feeling that
- It did not have to glide to a landing. This allows considerably more flexibility in the aerodynamics.
- It did not have to land horizontally. This is advantageous in two ways:
- There is no requirement to transition from powered flight to gliding flight in order to land; the spacecraft always lands under power, so it can make an emergency landing as soon as it gets rid of enough fuel to avoid collapsing the gear.
- Any flat patch of ground will do for an emergency landing site; no runway is required.
About the only thing the X-33 has going for it is that it behaves more like the Space Scuttle. Unfortunately, this similarity also appears to include development cost and schedule. Our current engines appear to be sufficient to build a much cheaper replacement for the Scuttle, and on a much faster schedule than X-33. In the mean time we are stuck with a vehicle designed in the 70's whose performance is a fraction of what was promised (65,000 lbs to orbit is only a dream) and requires a standing army of over 10,000 maintenance personnel to keep it flying. Worse, we cannot build any more and if we lose even one vehicle it will force other programs (like ISS) to be radically scaled back or even scrapped. Last, the engine technology of X-33 could be applied to a VTVL with little difficulty; however, with a going DC-1 program it would be forced to prove its worth instead of being locked in as part of "the only game in town". You can't escape the conclusion that the X-33 program is more about generating lots of money for contractors than making a cost-effective launch vehicle.--
Deja Moo: The feeling that
Sorry, I thought you might be getting a couple concepts mixed. As for commercial aircraft, you're right:many of them already require more space to land than to take off so it's doubtful that saving them 35 seconds or so of acceleration would be worth the cost of adding catapult gear to either the airports or airplanes.
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Deja Moo: The feeling that
This wouldn't be useful on something like the Space Scuttle (pun intended) because the stack cannot handle 6 G's. Something like a re-designed X-33 (Venture Star) could do it. And I suspect that NASA is suggesting it now because the X-33's design compromises have added so much weight that it can't carry a payload to orbit without several hundred MPH of head start.
Somebody, Congress, please boot the idiot NASA managers who selected the X-33 proposal and hire the guys who designed the DC-X; if we'd just continued with the DC-Y we'd have an orbital test vehicle by now! Oh, I forgot, the program was too cheap and didn't have enough slush to generate your campaign donations! Silly me!
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Deja Moo: The feeling that
- This concept is very old. It goes back beyond the British HOTOL aerospaceplane and all the way back to the Antipodal Bomber concept of Werner Von Braun in the 40's. Attributing it to NASA today just shows how backwards NASA is, and how clueless journalists are.
- Sewing machines and electric drills do not use induction motors. They use universal motors. Completely different technology. Again, clueless journalists.
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Deja Moo: The feeling that
While skin color and speech are patently obvious to anyone who can see and hear, how do you find out about someone's genes without taking a sample and doing a test? And without the knowledge of a person's genes, how can you use that to discriminate against them? If it is unlawful to perform the test, it's awfully hard to discriminate and not risk the penalties.
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Deja Moo: The feeling that
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!- Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
- Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
- The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not), and as it absorbed mass it would also absorb the momentum of that mass. Unless there is a transfer of momentum, the center of mass of the system would remain on the same path. This means that the mini-BH would very quickly wind up stationary at the center of the Earth.
- Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit. Without that, the inward pressure of the falling mass would only be balanced by radiation pressure from the accretion disk. Since an object on the equator only has the angular momentum to maintain a circular orbit at 1/64 of an Earth radius, at least 99.9996% of the Earth would be able to fall into the BH unless prevented by other mechanisms. The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001. See my previous comment about scattering efficiency and losses. I didn't say that Mars would be knocked out of orbit, I implied that the side facing Earth would be pretty thoroughly fried (a megaton/m^2 will do that). I'm pretty certain now that both Mars and Venus would lose their atmospheres (maybe only half of Venus, if the event went quickly).Were it possible for this to happen, the Solar system would not be a healthy place to be that day. It would be best to be somewhere far away on vacation, and deal with the insurance agent upon your return. And hope you have a "full replacement planet" policy. ;-)
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Deja Moo: The feeling that
I know we can't be sure which of these scenarios (if either) is correct, but it'll be awfully hard to find out except by running the experiment.
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Deja Moo: The feeling that
Genetic engineering isn't like a prep-school education. It's a technical practice and lends itself to automation. You can expect the price to come down very rapidly with time, like gene-sequencing and computers. Ten years after the rich start using it, it'll be a middle-class thing. Ten years after that, everyone will use it if they can benefit from it.
And what will people use it for? I can see some working to keep some of the "disadvantageous" traits of their ancestors, but escape the consequences. For instance, modify the sickle-cell anemia gene so that homozygote embryos fail to develop. This keeps the heterozygote resistance to malaria but avoids the health impact of a child getting one gene too many. Sure wouldn't hurt!
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Deja Moo: The feeling that
The thing that a lot of posters in threads like this forget (on purpose?) is that this technology, like any other, is not in the hands of the state here. It is in the hands of parents-to-be. People select their kids' genes all the time. They do it mostly by mate selection and a few by sperm/egg donor, but everyone does it nevertheless. All the gene manipulators will do is expand the pool of choices. The dystopian aspects of GATTACA are due to an entirely separate possibility, and that is genetic discrimination; it's distinct from the ability to engineer genes. If we can outlaw discrimination on the basis of skin color and go as far as we have towards eradicating it, we can almost certainly keep discrimination on the basis of genes from going very far.
So what are we achieving here with gene selection for our kids? I think that what we're buying is health and vigor, and happiness to the extent that healthy and vigorous people are happier than those who are not. How can this be a bad thing?
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Deja Moo: The feeling that