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The answer is zero in the case of your island with a one family, one son rule. There are no families with two boys. Getting back to your island, you can't change the gender ratio without culling, and we've ruled that out.

We're ruling out gender-biased abortions, gender-biased slips of the knife during birth, right? (These can and do bias the sex ratio.) Assuming that is the case, absolutely nothing done after the fact can change the sex ratio. Some scenarios: - Parents just have babies, stop whenever they want (or biology says "stop"!): 50% boys, 50% girls. - Parents must stop at the first boy, but must keep on having babies, maybe forever, until you have a boy: Still 50/50. - Parents must stop at either the first boy or at the nth girl: Still 50/50, no matter what value one chooses for n. - Parents can stop whenever they want except they must stop at the first boy: Still 50/50. You want logic? The logic is pretty simple. The cow remains out of the barn if one closes the barn door after the cow gets out. You want math? It's simple probability theory. No matter how one sets up the rules of the after the fact game, the sex ratio will remain 50/50. You want a simulation? It's going to agree with the logic and the math.

No, they can't. How? By law? There's no chance such a law could be passed now. There's no chance such a law could be passed in the next twenty years. Look at the demographics on religious beliefs in America. Such a change in the law might passable fifty years from now. Maybe. It's incredulous to you because you hate religion. Toss that hate aside and think just what that qualifier "free" in "free exercise" entails. Read Burger's decision. Two parts, one of which strains your (but not Burger's) credulity; the other you intentionally cut in your quote of my post. I'm not a religious person. I'm very far from it. I'm also realistic in seeing how far in the minority my personal stance is. Yours is a Mittyesque dream that will never see the light of day. You are tilting at windmills. Bringing coal to Newcastle. Nailing jello to a tree. Asking the sun not to shine. Herding cats. Carrying water in a sieve. All of the above, and more.

Do not take the following the wrong way. That the car of today is much more reliable, cheaper, and better than was even dreamed of half of a century ago is a mostly due to you industrial engineers. Cars are but the tip of the iceberg. Industrial engineering has played a key part in the vast improvements in reliability, quality, and cost. And a whole bunch of other -ilities. That said, your field, industrial engineering, is a bit faddish and imprecise. It has to be. You are dealing with very complex systems, with economics, and with that most fickle, unpredictable element of all, people. You IEs are inevitably grasping for straws a bit. Some of that grasping: "TQM!" "No! Six Sigma!", "ISO 9000!" "No!! CMMI!", "Top down!" "No!!! Bottom up!" It's all a bit reminiscent of the "Tastes great!" "No! Less filling!" campaign. Just because your field is a bit (more than a bit) ephemeral does not mean that physics is. Physicists have very solid reasons to think that there is no such thing as "free energy", where "free" means energy is not conserved. You've already seen conservation of energy and Noether's theorems in multiple posts before this. If you truly are interested in learning, you have already googled these phrases. Another set of things you should look into are the laws of thermodynamics. A humorous summary: Law #0: Any source of energy must abide by the following laws of the game. Law #1: You can't win. Law #2: You can't break even, except on a very cold day. Law #3: It never gets that cold. The first law of thermodynamics is conservation of energy. The second law is even more stringent; it says that the only way to get 100% efficiency is to have zero friction and a heat sink at absolute zero. The third law says there will always be some losses somewhere. You can't get 100% efficiency no matter what. No matter what twists to the laws of physics need to be made to describe some weird results from some experiment, the laws of thermodynamics will almost certainly remain unscathed. This is why the patent office automatically rejects any patent that claims to bypass the laws of thermodynamics. The only exception is a working device. No such device has been built. No such device can be built.

John Cuthber's answer is correct, with two assumptions: - That girls and boys are born in equal proportions, - That death rates for males and females are equal, at least up through child bearing age. Neither assumption is quite valid. Males slightly outnumber females at birth, about 105:100. Death rates for males also slightly outnumber that for females at all ages. The sex ratio becomes extremely close to 1:1 by the time those babies in a 105:100 male:female ratio grow to child-rearing age. This 1:1 ratio at child rearing age is not a fluke. It's true for many species. It's called Fisher's principle. However, this is a detail that is intentionally being ignored in this problem. The assumed ratio is 1:1. An after-the-fact action such as stopping at the first boy won't change anything. Suppose the question was modified so that a couple stops having babies after having the fifth girl or after having the first boy. Naively this would seem to bias things strongly in favor of girls. It doesn't. These after-the-fact actions are closing the barn door after that 50/50 cow has already escape. The only thing that can change the sex ratio is to change that 1:1 ratio (more realistically, 105:100 ratio) at birth. Pregnant women might abort fetuses in a gender-based manner, or newborns might die during or right after childbirth (and not count) in a gender-biased manner. Both apparently are happening in China as an unintended consequence of the one family, one child rule and societal biases that favor boys over girls.

I think that this windmill will break your lance to bits and throw both you and your horse to the ground. How are you going to accomplish this? Certainly not by arguing that it's unconstitutional. That's been tried before, Walz v. Tax Commission of the City of New York. That governments can allow tax exemptions for religious organizations is constitutional. While the Court was only asked to decide whether religious tax exemptions are constitutional, the wording of the opinion strongly implies that not providing such an exemption would be unconstitutional based on the free exercise clause of the first amendment, “or prohibiting the free exercise thereof”. Certainly not by legislation. No legislature in the US would pass a law that removes the tax exemptions for religious organizations. Even if they did, it wouldn't last long. The people would vote the responsible legislators out of office, and they wouldn't wait for the next election. They would find some way to hold a special election to toss those legislators out. Even if that didn't work, the constitutionality would be challenged based on the free exercise clause and Walz v. Tax Commission. You would need a constitutional amendment to accomplish this. That's not going to happen, either, not for a long, long time at least. Look how many people still think the Earth is 10,000 years old. There are signs that this nonsense is finally waning, but slowly, and only amongst younger Millennials.

Vacuum energy and the Casimir effect are perennial favorites of cranks and charlatans. One problem: It won't work. There's no way to extract energy from it; vacuum energy is the lowest possible energy a system can have. Tapping energy out of vacuum energy would violate conservation of energy. No matter what physicists come up with to further explain the nature of the universe such as melding quantum mechanics and general relativity, those conservation laws will almost certainly remain inviolate. Google "Noether's theorems". If not vacuum energy, what other explanations for dark energy could we take advantage of? The easiest explanation of all is that dark energy is Einstein's cosmological constant. There's nothing there to tap. Nothing. How about some conjectural explanation from string theory, quintessence for example? There might be promise there, but only if you can recreate the energy conditions right after the big bang, and only if you do so with a machine that spans hundreds of galaxies. There might be something there, but it is so far, far out might as well say that it doesn't exist. And it still wouldn't be free energy. Conservation of energy is as close to being sacrosanct as any concept in physics can get.

In other words, an over unity device. Sorry. It doesn't exist. Learn some physics.

Four tricks. #1. Something he didn't do, which is to try to extract energy from the device. If he did that the wheel would soon come to a stop. #2. Something else he didn't do, which is to show the wheel running for more than a few seconds. If he did that the wheel would once again soon come to a stop. #3, Something he did but didn't show, starting at about 1:05. Where is his left hand? It's offscreen and is giving the wheel a spin. This is an out-and-out cheat. #4, Something he did and did show, starting at about 1:30. He slowly pulls the magnet back to get the ball to lift and get the wheel spinning. Then he pulls the magnet back a little more to get the wheel rotating a bit faster. Still a cheat. He's adding a tiny bit of energy to the system. Eventually the tiny bit of energy that he did put into the system will dissipate (trick #2), and there is no way to extract more energy out of the device than the tiny bit he put into it (trick #1).

Correct. That door only exists in the minds of crackpots and charlatans. This is a perpetual motion machine of the first kind. You won't be able to patent such an invention, and if you build one, it won't work. This door does not exist. If you mean solar energy, sure. But that's not perpetual motion. If you mean something else, no. No. That's because perpetual motion machines don't exist. They can't exist. Sorry.

This one looks promising:

Reason #3 this wouldn't work. You're closing the barn door after the cow got out. Bald men don't father all that many babies. Young men who may or may not go bald in another 20 years or more are the ones who father babies. By the time those men do go bald they are all done with the Daddy business.

Torture doesn't work, no matter what form it takes. Torture people long enough, hard enough, and they will till you anything to stop the pain. The information garnered from torture is useless. The same applies to torturing data. Numerology is torture, and it doesn't work.

This wouldn't work for two reasons. Reason #1 is that it's targeting the wrong gender. Genes from the father might alter the pattern, alter the susceptibility, but baldness is primarily passed from mother to son. A culprit has even been found on the X in a gene that regulates androgen receptors. Having all bald men stop fathering babies (and how are you going to accomplish that?) would do nothing with regard to the goal of eliminating baldness. Reason #2 is that it's pure evil. The only way to stop men from fathering babies / women from having babies is to sterilize them. Forced sterilization nowadays is a punishment reserved for the worst of sex offenders.

Well that's just boring, unless the three of you are pan dimensional beings.

You understand incorrectly. Astronomers see objects very far away in every direction, not just the where the Hubble Deep Field was taken. Every direction. So does that mean that we are the center of the universe? In a sense yes, but a better answer is no. Astronomers in one of those far, far away galaxies would see exactly the same thing, that the they can look in any direction and see objects that are very far away, and the further afield they look the higher the recession velocity. So does that mean that that far, far away galaxy is the center? The answer is that same as before, in a sense yes, but a better answer is no. The better answer is that the universe doesn't have a center. If one of the many multiverse conjectures is true (which, BTW, is off-topic for this thread), the concept of a center of the multiverse makes even less sense than does the concept of the center of the universe.

That depends on what you mean by "how does it work?" You looked at it from the perspective of those silly laws of physics. If you look at it from the perspective that there are lots of very rich people out there who love to invest in crazy schemes and who think that laws (apparently including the laws of physics) were made for little people, well, there's another business motto that applies to such people: A fool and his money are soon parted. Cold fusion has worked quite nicely as a scheme for some to get rich off of those rich but technically naive people.

Mars One has been discussed here to some extent already. See http://www.scienceforums.net/topic/66606-terraforming-nearby-planets/, posts #65 and on. Mars One is nonsense. It's the basis for a TV reality show with no basis in reality. I suspect the founder reads science fiction. I can think of at least a couple science fiction stories that funded (and profited from) space exploration this way, and all of those pre-date Big Brother. I suspect he read those stories and thought "Big Brother! This can work!" Except it can't. Look at those drawings on the Mars One web site with landing capsules right next to one another. How's that going to happen? Our current landing capabilities would have those capsules spread out over hundreds of square kilometers. His proposal needs extremely pinpoint landing. We don't know how to do that yet. The site says with a hand-wave that the crew will grow their own food. It says nothing on how to do this, nothing on the numerous projects where hydroponics inevitably fail. We don't know how to do this yet, either. The site posits electrical power from thin film solar cells. The thin film cells are needed to keep the weight down. What's going to happen to that array of thin film cells when the first Mars dust storm comes by? What happens at night? There are no batteries in the proposal; batteries weigh too much. The site posits obtaining water and oxygen from the water in the Martian soil. What water? Except for the poles (and this isn't landing at the poles), Mars makes the Mojave desert look like a lush paradise. Even if there was water, we don't know how to mine it and refine it. Just because we can mine and refine on Earth does not mean that technology will work in a vastly different and very hostile environment. There's a whole of stuff in his proposal that falls into the "we can't do that yet" category. Hand-waving the problem away by saying he's only using existing, proven technology does not work. There is almost no existing, proven technology in this proposal.

It depends on how far away the GRB is. There's a mistaken conception that laser beams are parallel (and GRBs aren't as good as laser beams). They aren't. The best one can do is a Gaussian beam, which lasers come very close to being. There's still going to be divergence. The only way to avoid divergence is to have an infinitely-wide source. A commercial grade laser has a beam divergence of about 0.05 degrees, and some used for long range communication reduce this by a factor of ten. Gamma ray bursts have a beam dispersion between 1 and 20 degrees, depending on the type and depending on whose article you read. If Alpha Centauri emitted a GRB (which it can't, so don't worry) aimed at the Earth, the beam would be over 10,000 AU across by the time it reached the Earth.

Even better, try it with a large soda bottle with a narrow opening. Do it right and the water won't come out at all! The answer is a combination of atmospheric pressure, surface tension, viscosity, and whether there's a free surface. The water will poor smoothly if you tilt the container only slightly. That's because there's a free surface for air to flow into the bottle above the water at the same time that water is flowing out. When you fully invert the bottle there is no free surface. The air inside the bottom will be at less than atmospheric pressure after a glug of water comes out. The pressure at the opening will keep the water from coming out. A glug of air can go into the bottle, but only if the opening is wide enough so that surface tension doesn't come much into play. Now the pressure is more or less equalized, so a glug of water can come out. The cycle repeats. If you watch carefully you'll see that the glugs get bigger and bigger as the bottle empties.

Rich, you completely missed the point about planetary migration. It happens during the formation of a planetary system. When a newborn star ignites it blows away all the gas and dust in the protoplanetary disk. Migration pretty much stops when the star ignites and does come to a stop when the planetary system has stabilized. Our solar system stabilized about 4.5 billion years ago. The planets haven't moved much at all since then. Your conjecture regarding gas as the explanation is flat out wrong for a number of reasons. One is that a substance compromising a solid and a gas dissolved in that solid behaves like a solid, not a gas. Another reason is that the 1977 article you cited is based on estimates from that time regarding how iron behaves at very high temperature and pressure. Scientists have developed the tools and techniques needed to create those high pressures and temperatures in the 30+ intervening years since that article was published. Those 1977 estimates weren't quite right; it doesn't take near as much low density elements as posited in that article to explain the apparent density deficit in the Earth's core. Yet another reason is that heat flows from the core outward, not from the surface inward. Heating the Earth's surface would not heat the core. It would at best slow down the rate at which the core is cooling. You don't like plate tectonics because of Pangea. That's silly. Just because your middle school teacher couldn't teach the topic, the text was oversimplified, or you misheard / misread does not mean the theory is wrong. It just means that you had a lousy teacher, a lousy text, or that you misheard/misread. The fact is that the mechanisms why Pangea and other supercontinents formed and broke up are fairly well understood. BTW, it's not just Pangea. Several supercontinents have formed and broken up. Pangea was just the last of several. One last point: In your answer to my questions, you have essentially added plate tectonics to your model that you created explicitly to get rid of plate tectonics.

The Sun, yes, the Moon, no. Assuming that a GRB can come from anywhere in the sky with equal probability, the odds the Moon or Sun would be in the way are one in 185,000 or so due to the ~32 arc minute angular diameter of the Moon and the Sun as seen from the Earth. That is where the similarities end. You have to consider the size of the shadow. The Sun would shadow a chunk of the sky that is 10,000 times the size (cross-sectional area) of the Earth. The Moon's shadow would be tiny, about 7.5% of the Earth's cross-sectional area. That 7.5% protection: It's nothing. With one exception, the gamma rays from a GRB won't hit the Earth's surface. That one exception is a GRB that is so close that it blows away more than half the Earth's atmosphere. A more remote GRB will "only" dissociate the oxygen and nitrogen in the upper atmosphere. We'd say good bye to the ozone layer and hello to long-lasting stratospheric smog of nitrogen dioxide. Whether the Moon is between the GRB and the Earth would make essentially no difference on the outcome.

No, you can't. Bell's theorem says that there are no local hidden variables. This means any viable interpretation of quantum mechanics either has to throw out realism or locality. Realism: The Moon is still there when no one looks at it. Locality: No spooky action at a distance. So what if the "correct" interpretation of QM is to maintain realism? Wouldn't that imply that FTL communication might be possible? The answer is no. There are a number of "no signaling" theorems that start from a basic set of assumptions to show that FTL communications cannot happen. Every viable interpretation of QM obeys those assumptions, even those that reject locality. So even if the universe truly is non-local, FTL communication still can't happen.

Don't attribute every grandiose statement to Einstein. The ones in question are Emily Noether's, not Einstein's. Noether's Theorems are very, very profound. Yet we test. We have to. It's a part of the divorce decree between physics and philosophy. Physicists have to test their ideas and use trash cans when their ideas don't pan out. Philosophers are free not to do so, but they do have to ask whether the customer wants fries with their order.

Just because you don't understand something does not mean that it is not true. Your argument is straw man and an appeal to ridicule, a fallacy. You have created this false concept of a "exact polar opposite" and then ridiculed it. No such focal point is needed. All that is needed is the Earth acting as huge heat engine and the huge density and thickness differences between continental and oceanic crust. A supercontinent breaks up because the thick but low density continental crust forms a big blanket that keeps interior heat inside the Earth. The thin, high density oceanic crust lets that heat bleed through. This makes for a large temperature gradient from seashore to the center of the supercontinent. The supercontinent bulges in the middle until accumulated stress makes the supercontinent start to break up. The build up of heat opens up plate boundaries into which pours new oceanic crust from below. The supercontinent breaks up with new oceans separating chunks of the old supercontinent. That breakup can't continue forever. One of two things can happen with the newly formed continents: 1. They will continue to drift around the globe, eventually hitting each other again after circumnavigating the globe. 2. They will eventually cease drifting and then drift back together, eating up the oceans that just formed between them. The first process is fairly easy to understand. This requires such a huge buildup of heat that new oceanic crust keeps forming and forming. The diverging continents eventually re-meet on the other side. The second process results when the heat buildup isn't quite so large. That new ocean opens a new avenue for heat dissipation, thereby diminishing the driving force behind the breakup. Eventually the new ocean ridge becomes dormant, but only after having created a bunch of relatively thick oceanic crust. This represents a imbalance of potential energy. That oceanic crust diving under the light continental rock would ameliorate that imbalance. The continents reverse direction and glide over the ocean that just separated them. What about option #3, the continents just stop and stay separated? That is akin to an inverted pendulum. It isn't stable. One way or the other, physics demands that the continents come back together to form a new supercontinent once the energy imbalance has been corrected. Regarding my questions, 1. Apparently you do not understand what "statistically significant" means. Aside: Let's take your dislike for Pangea to its expanding Earth extreme, that there was no ocean at that time (BTW, this is wrong, wrong, wrong. The oceans came first, not the continents.) This means 220 million years ago, the Earth had a radius of 3300 km, which (if the rate is linear) means a growth rate of 14 mm/year. This hypothesis can be rejected by that measurement of 0.1 mm/year ± 0.2 mm/year. You can't go back 4.5 billion years with an expanding Earth. It's junk. 2 to 4. Your responses are, well, Rich, Rich. You have added plate tectonics to the expanding Earth theory! 5. The average density of the Earth is 5.52 grams per cubic centimeter. Just divide the observable mass by the observable size. You need to explain this. You can't with gas. You need something very, very dense. 6. Your response was non-responsive. The outer core is liquid, not gas. It can't be a gas. The observed seismic waves are inconsistent with a gas, even a highly compressed one. The inner core is solid. It can't be anything but. We see shear waves. Gases and liquids do not support such waves. The concept of a gas-filled Earth is ludicrous. It is physically impossible. Expanding Earth meets hollow Earth? Come on.