The force of gravity between masses and the force of electricity between charges are distinct and separate. Experimentally and observationally, the electric force is tied firmly to the speed of light. This has NOT been observationally established for gravity, but has only been theorized. It has been theorized by no one less than Einstein, but is still nevertheless an unverified aspect of his generally verified theories. Relativity only begins to have practical effects at relative speed much greater than any orbital velocities. At the actual measured orbital speeds, Newton is firmly in charge. The original article states that this highly sensitive LIGO detector specifically designed to detect gravity waves, so far has detected nothing. The fact than no one has so far managed to make any kind of shield or barrier to gravity shows that the force of gravity is fundamentally different and distinct from the electric interaction to which the speed limit of light applies. Newton clearly says that gravity is independent of time. So far, there are a number of theories and fancy mathematical constructs that say differently, but no experiments or observations to back these theories up.
.......we're talking about gravitational radiation.......
Can you point me to an actual experiment or observation of such radiation being detected? I'm not talking about somebody's THEORY, even Einstein's, but real scientific measurements here. In the original article it was stated that no gravity waves were detected with a very advanced instrument built especially for this purpose. Not detecting something is often just as important and finding it. The Aether's existence, as postulated back then was disproved by showing its absence.
Measurements and observations must ALWAYS take precedence over *any* theory, no matter how widely held it is or how famous its originators are. Dark matter/energy are another theoretical construct that have never been observed. The Oort cloud as the source of comets is another theoretical fiction that has never been shown to exist. The red shift is well observed and measured, but its cause being theorized as the doppler effect is pure assumption, (belief) just as much as any belief of a religion.
For example, we know by experiment and every day practice, that gamma and x-rays are produced by the acceleration of charges. If the theorized bodies, such as neutron stars and other objects are NOT electrically neutral toward each other, then enormous electric fields could serve to accelerate charged particles, usually electrons, to immense energies. We also know by every day experiments that moving electric charges produce magnetic fields. We also observe that these magnetic fields tend to force these charges to NOT travel in a straight line, thereby releasing synchrotron radiation, ie. gamma rays. These fields also tend to focus these charged currents into narrow beams. You can sometimes see this effect in a neon sign. We also commonly observe that when fast moving charged particles suddenly slam into an obstacle they also produce large quantities of radiation. Could it be that such well known, researched mechanisms might be responsible for these radiation outbursts we observe? Could it be that gravity is not in the least involved in this and that's why we have not observed gravitational waves from this or any other source? If bodies, such as the sun and the planets are not electrically neutral, and there is evidence (solar wind) that they are not, the electric fields and currents around and between them would certainly affect electromagnetic radiation passing through those fields and currents. Thus what is thought to be "gravitational lensing" deflecting electromagnetic radiation, could also be caused by the electric and magnetic fields surrounding highly charged objects, such as the sun, such as in Eddington's observation during the solar eclipse. He observed a deflection of light, but he INTERPRETED that observation as being due to gravity.
(...information has traveled faster than light. Which is not possible....)
Information and its carrier are distinct. If there is a carrier that can go faster than the speed of light, then so can information. It is theorized by no one less that Einstein that gravity too is subject to the speed limit of light. However this has not been EXPERIMENTALLY or observationally verified. Gravity is a very weak force, quite distinct from the other forces of matter. It arises out a still mysterious property of matter we call mass. Until we know what it is about matter that causes it to have this thing we call mass, gravity will not be understood. We do know that both gravity and the electric interaction are long range forces and therefore can and do affect the universe as a whole.
It is NOT science when one makes up theories that have no basis in actual repeated observation or experiment. Einstein's theories have many aspects. Some of these aspects have been experimentally verified to many decimal places of accuracy. Others, such has some of his ideas about gravity have not, at least as far as I know. He did not like quantum science all that much, until experimental evidence piled up. Questioning Einstein is akin to heresy in religion, but I am under the impression that science is different, that it is based on observation and experiments. Maybe I am wrong about that.
..... clocks running slower in higher gravitational fields......
What force governs these clocks? Is it not the electric force that governs atoms? Of course, we know that gravity affects atoms and atomic behavior. That's why light that travels close to the sun gets deflected slightly. Also, if the sun in its entirety is not electrically neutral, any charge it carries could also affect electromagnetic radiation in a very small way. There is evidence that the sun is NOT electrically inactive, by the measured fact of large solar magnetic fields. We know of no source of magnetism apart from the movement of charges.
The motions of heavenly bodies is way too slow against each other to be materially affected by relativity concerns. Yes, your watch runs slower atop Mt. Everest than at sea level but it is a trivially small effect. In equations you not only have to look at the math, but also the relative sizes of the numbers involved. Relativity doesn't change the orbits of planets or galaxies in any amount we'd be able to measure. In the world we actually live in, relativity can be safely ignored in most instances.
....arguing gravity is instant using Newton is pointlessly wrong......
There are very few, if any masses, that give rise to appreciable gravity, that are moving anywhere near fast enough to allow relativity to come into play. Yes, theoretically, there is an effect, but it is trivially small. For all practical purposes, the solar system and the galaxy motions are governed by Newton. Einstein doesn't get into the act until you get near the speed of light. No mass subject to gravity moves very fast compared to light. Also, nobody has ever MEASURED a speed factor for gravity. Maybe gravity is not instant, but just faster than we can measure, just as light speed was so fast it also could not be measured until our technology got good enough. Until somebody actually DOES measure it, I think it is safe and practical to go with Newton and assume that for present purposes, gravity is not subject to time, at least not in our present frame of reference.
(.....Relativity applies everywhere....)
As far as we know it does. However, physicists still have a hard time fitting gravity into the framework of quantum science and the other forces of nature. We know is that mass somehow gives rise to a force we call gravity that accelerates mass. We can measure gravity and time, but don't really know yet what either of these really are and how they fit the puzzle of our universe. BTW, there is no law of physics we know of that demands that the speed of light be constant. That is an assumption we make. It is tied with another assumption that the red shift we observe is due to the doppler effect. Increasingly, data from modern advanced telescopes and space probes puts both of these assumptions on an ever shakier base. If the red shift is due to a fundamental change in the properties of space, as the universe expanded, the red shift would be telling us that the speed of light is much less now than it was when the universe was smaller and denser. There is nothing as constant as change. We have to very carefully examine our uniformitarian assumptions, even if they seem very comforting to us.
....Space (distance) and time are rather intricately linked in Relativy,....
The equations of gravity are simple and do NOT contain a time element.
Force of Gravity = G*(m1*m2)/r^2
where G = gravitational constant, m1 and m2 are the masses of the objects and r= distance between them. There are NO time values, which would imply speed. Electromagnetic equations DO have time values in them. Also, the constant G is a dimensionless number, whereas the "constants" that apply to electromagnetic interactions (c and it inversely related h) have time attached to them. Now the ACCELERATION produced by gravity DOES have a time unit, but gravity itself does not. Thus, the FORCE that two orbiting bodies experience via gravity must be instantaneous, or at least incredibly fast.
Since the orbital speeds are very much less than the speed of light, relativity doesn't enter the picture.
For the electromagnetic interaction, relativity has been experimentally shown, but gravity is still pretty much a mystery. We know that matter somehow gives rise to an acceleration we call gravity. There is no way to tell the difference between this acceleration due to gravity and the acceleration of matter by some means. There is no experiment you could do inside, if you were sealed into a closed rocket, to tell whether your cabin was being accelerated through space at 32ft/sec/sec or if that cabin was simply parked on the launch pad on earth.
We also know by experiment, that the gravitational interaction is some 36 orders of magnitude smaller than the electric interaction. Two neutron stars or black holes in close proximity, could have way more influence on each other and the radiation emitted, by way of the electric interactions between them, than by gravity.
Sure, the theory of relativity asserts that gravity is also subject to the speed of light, but that part of relativity has never been experimentally verified. Newtonian mechanics mandate that gravity ITSELF not be in any way be impacted by time. Only the ACCELERATION produced by gravity has a time value. Since the planets and galaxies don't move relative to each other at anywhere close to the speed of light, relativity doesn't enter into the picture here.
..... it has been observed that the system loses energy (causing the stars to get closer together) at a rate exactly equal to the predicted production of gravitational waves.......
We measure a rate of energy loss that happens to correlate with the theory of how gravity waves might be generated. So, since when does correlation guarantee causation? Is it possible that the energy loss, even though it correlates with present theory, nevertheless has a different, perhaps yet unknown cause? Maybe there are other forces at work, besides gravity? After all, gravity is the weakest of all known forces by which matter and energy interact.
...It is integral to the equations that model electromagnetic phenomenon.....
True. It is however NOT integral to equations that describe gravity! There is no time value in them. That could mean that gravity is independent of time and therefore speed. Therefore, if someone turned on a gravity generator or suddenly removed a gravity shield, the effects of that should be instantaneous, or at least very fast over large distances. Until Mr. Roemer first measured the speed of light, it too was thought to be instantaneous. Maybe someday the speed of gravity will be measured. If it is, the speed of light will be at snails pace comparatively.
The sun and the center of our galaxy are in gravitational "touch" with each other NOW, not how they were thousands of light years ago.
..... As far as we know, there is no way for information to travel faster than light......
And just WHERE do you get that idea? The speed at which information can travel is limited to the speed of its carrier. If you can find a carrier that travels faster than light and put the information thereon, that information can arrive much faster. What is the speed of gravity? What about the speed of thought? Gravity must be instantaneous or at least very fast. The sun and the earth "feel" each other where they are NOW, not where they were 8 minutes ago. Gravity itself seems to be only dependent on mass and distance. Nowhere does time enter into its operation. Now the equivalent ACCELERATION of gravity does have a time element.
..... It basically means you're assuming that causality exists......
Why do you jump to that conclusion? Gravity has to work either instantaneously or incredibly fast. The sun holds the earth in place where it is NOW, not where it was eight minutes go. Gravity doesn't involve time, only mass and distance.
.....there is a fundamental and unproved ASSUMPTION in Physics that gravity waves must travel at the speed of light......
If gravity WERE as slow as the speed of light, the sun would have long ago lost its planets and itself would have left the galaxy. The equations for gravity don't have time values. That should tell us something.
....The General Theory of Relativity says they should move at the speed of light......
If gravity is confined to the speed of light, the Sun should have lost its planets long ago. For example, simple Newtonian math tells us that the Sun and Jupiter "KNOW" about each other right NOW or in a very short amount amount of time, not 43 minutes later. the Earth and the Sun "feel" each other's gravity instantaneously, not with an eight minute delay. The sun and the center of our galaxy communicate by gravity without a many light year time delay. Otherwise, the galaxy would fly apart.
Matter and electromagnetic energy have a speed limit, but gravity either doesn't have a limit at all, or it is incredibly high. Gravity equations do not contain any time values, only mass and distance.
.....Normally such bursts arise from well known phenomena,.......
A well known way of generating x-rays and gamma rays is to accelerate fast moving charges, usually electrons. Instead black hole collisions, could it be that immense galactic electric fields accelerate huge quantities of free electrons to stupendous energies? These electric currents then give rise great magnetic fields which force the electrons to emit intense synchrotron radiation which we can detect? We routinely do this sort of thing at places like the Synchrotron Radiation Lab at Stanford. They can generate the most intense gamma radiation bursts made on Earth.
Maybe the fast moving electrons collide with an object, abruptly slowing them down like a target in a cosmic x-ray machine? Bremstrahlung effects like this would not leave any gravitational signature, since there are no large masses, such as black holes involved.
.....comes with a built in monitor that cannot be kept after the end of the macs usefull life........
The useful life and resale value of Macs is considerably higher than a similar aged PC. Check out e-bay for that. I bought my younger daughter a Macbook to replace her G4 iBook so she could also use Windows at her university. I now use her old iBook G4 as a very capable media machine connected to a digital projector and our stereo system in the living room. It plays back DVD's and iTunes material. I gave my 7 year old Titanium G4 Powerbook to a friend of limited means and he is as happy as a lark. He is using its built in S-Video connection with his Sony TV to show movies and photos, as well as mail and web surfing via the built in wireless. His much newer, faster Windows desktop machine has fallen into disuse, gathering dust, despite the fact that the old Mac is rather slow. The PC will not connect to his TV set without added hardware and software.
(.....has space for only one internal hard drive though it is a proper desktop model......)
I have a portable 500G firewire HD which will connect to any Mac. It will transparently boot any of them in case there is a problem and also serves as a backup for the data on all of our Macs and one PC. Being external, it only gets powered on when actually needed, rather than running all the time like a built in drive would. This means it should last a long time. Even though firewire is spec'd slightly slower than USB2.0, in practice it is faster. I have never heard of an external HD setup for PCs that will boot any laptop and also any desktop system. They have system specific setups. I've used this capability to restore damaged file systems on some other people's Macs. Being able to buy a family license for 5 Macs for not much more than one legal copy of Windows XP Professional or Vista, as well as avoiding all activation hassles is no small potatoes either.
I don't go in for games, but everything I've read, Macs don't have many good games available for them. For all other uses, their graphics is more than adequate. My teenage son likes games, so I bought him an x-box for those. He can also run Windows on his Macbook, but he doesn't use it for games. Over the long term, Macs are more economical, even though they cost more to buy initially, than Windows systems.
......That's not even getting into how inefficient it will be.....
Oh yes, it would be more efficient in terms of energy used and less pollution. However most, if not all of these brilliant urban planners who dream up stuff like this don't consider the value of people's time and convenience. In Europe, everything is much closer together than in the US, especially the western parts. There and in the core of the largest US cities transit works pretty well.
Even if it takes X amount of time on transit or the same in a car stuck in traffic, many will opt to still take their car for the door to door comfort and quiet of a modern automobile. In the end, this will only be the equivalent of another tax on motorists which the politicians will be able to spend on purposes having little or nothing to do with transportation.
....to get features that are standard on PCs......
So what features, other than an expansion slot does a "standard" PC have that an iMac or Mac mini doesn't? If you already have a nice monitor and keyboard, get a Mac mini. If you have a valid copy of Windows, the 2.0Ghz duo will run that quite well with a virtualization program at he same time as OSX10.5 in case you have some Windows apps you really need. You can also use the included Bootcamp program to install Windows, just as you would on any PC.
Forget about high graphics games however. Basically you then would have two machines in one. A virus free Mac and a Windows box for all your favorite programs you may already own. You can even add your favorite flavors of Linux to fool around with if you use a virtualization program, such as Parallels 3.0. I've read that anyone moderately skilled with tools should be able to open the mini to install more RAM and a bigger HD.
The printed $1/watt solar panels could certainly help with our energy problems.
Do you really think that "political correctness" in hiring is more important than hiring the right person for a job? If you do, your investors, if any, may be left holding the bag.
.....There is no 'Mind', and it is therefore meaningless to speculate on what that 'Mind' might want.......
You don't KNOW that, but you believe it because you WANT to believe that there is no God. You hope it lets you out of your responsibility to Him as your Creator.
I do respect your decision to reject God. God has given you the freedom to reject Him. He could have made us like a deterministic, highly intelligent computer, but then we would not be capable of love. You know that if suddenly there appeared on you computer screen: "I love you --- (your name)" that someone was messing with that computer and that it means nothing to you. On the other hand if your spouse or child expresses that love, you respond very differently. The computer doesn't have the capability of love. You do, first of all toward your fellow humans and by extension toward God. All this has nothing to do with religion, but how we are all wired. When someone expresses this love by sacrificing his/her life, they are acting against all principles of "the survival of the fittest" as formulated by Darwin.
Maybe, if you live long enough, you'll begin to understand that there is more to life than science can explore and reduce to a mathematical formula.
.....Still makes just as much sense, and is just as believable.......
Indeed true! That's why, at the core, science is just as much based, at the root, on FAITH. Human rules or laws come from human minds. So then what MIND thought up the laws of nature? You can give that Mind any name you wish. Call it evolution maybe even. There is no way science can observe the existence or non-existence of this Mind. Evidently, this Mind doesn't want to be proven, but rather BELIEVED and trusted.
All children tend to believe their parents and other adults they get to know. Only after they have been lied to by someone they initially trusted, especially by someone who hates or dislikes a parent, do they become doubters and distrustful. They may even come to hate their parents, though these may have done an above average job in their parenting.
In Genesis we read about the first parent, God. There too, the kids first trusted their parent. We are told that another entity came and lied to these children of God and they believed the lie. Most of mankind still believes the lie about their Creator. The central idea of this lie is that man is an independent, sovereign creature in no way accountable to or dependent on a higher Power, their Creator and ultimate parent.
Goebbels once said: "If a lie is bold enough, outrageous enough and repeated loud and often enough, then those who believe that lie will believe it to be the truth.
....I'd naturally have to consider it in light of other, more plausible explanations........
It depends on whether you WANT to believe or not. Jesus said that even if someone were to come back from the dead, those kind of people would not believe whatever such a returnee would say. NOTHING can convince someone to believe anything they don't want to believe. Don't confuse me with the facts, my mind is made up.
......There are only three "articles of faith" for a scientist. The first is that everything in the universe can be explained in terms of a set of rules, regardless of the extent to which we know and understand the rules. The second is that these rules apply without exception to everything in the universe. The third is that the rules are unchangeable..........
There are only three "articles of faith" for a Believer. The first is that everything in the universe can be explained in terms of God, regardless of the extent to which we know and understand the Him. The second is that God controls without exception everything in the universe. The third is that the God is unchangeable.
There, changed it slightly for you. I could add that, like human rules, someone made them. Maybe God is the one that made the "rules" that scientists BELIEVE in.
....but still priced well above the entry level models.....
Give only one good reason why Apple should get into the low profit rock bottom profit killing entry level computer business? If you can't afford a shiny brand new Mac, look around on ebay. A two year old G5 will likely be still better than a rock bottom new Windows system.
.....Every other major manufacturer manages to produce a cheap machine.....
Is it so hard to grasp that Apple doesn't build cheap stuff? Is it so hard to figure out that BMW doesn't make cheap cars? If you can't afford a Mac Pro get a cheap Dell. If you can't afford a BMW, a Yugo. A Dell computes (most of the time) and a Yugo will usually get you across town.
.......Does the employer have the right to know if a potential employee is gay? Muslim? A Democrat? A non-vegetarian?.....
You did not read my post very carefully. None of the things you mention above affect job performance in most situations. Probably, a church would not hire a gay or Muslim because such a person would, by definition, have a world view opposed to that of most churches. Some churches might not hire a Democrat:-) ! If one employer feels that a certain drug doesn't affect the job then that employer should be free to hire such a drug using employee. If another employer feels just the opposite, they should be free to reject such a drug user. It should in no case be the government that forces employers either pro or con in that particular issue. Anything that affects a person physiologically, WILL affect their job performance. Even off the job drug use can. Now, an employer may not care about that and therefore should be free to hire a druggie if it is not a safety issue. I certainly would not get on an airplane, if I knew the pilot is a druggie.
On the other hand, the government SHOULD have a say against job discrimination on grounds that a person cannot change, such as sex, race or national origin etc. Even there, a fire department should not be forced to hire a 90lb woman for a job that might require carrying a 200lb man out of a burning structure. Some common sense and discretion ought to be used in certain situations.
....Don't tell me that you are justifying workplace drug testing on the basis of "productivity"........
Don't tell me that someone using drugs (legal or illegal) is a more desirable, more productive worker than someone who doesn't use or need those? Don't you think that an employer should have the right to know and intelligently choose between a drug user and someone who does not use nor need such things, just as a person has the right to use or not use drugs? Nobody holds a gun to a person's head and forces them to become a druggie or alcoholic. The use of these substances clearly affects a person, both on the job and off the clock. As a person sows, to they shall also reap.
Slashdot Mirror
....Most likely incorrect.....
The force of gravity between masses and the force of electricity between charges are distinct and separate. Experimentally and observationally, the electric force is tied firmly to the speed of light. This has NOT been observationally established for gravity, but has only been theorized. It has been theorized by no one less than Einstein, but is still nevertheless an unverified aspect of his generally verified theories. Relativity only begins to have practical effects at relative speed much greater than any orbital velocities. At the actual measured orbital speeds, Newton is firmly in charge. The original article states that this highly sensitive LIGO detector specifically designed to detect gravity waves, so far has detected nothing. The fact than no one has so far managed to make any kind of shield or barrier to gravity shows that the force of gravity is fundamentally different and distinct from the electric interaction to which the speed limit of light applies. Newton clearly says that gravity is independent of time. So far, there are a number of theories and fancy mathematical constructs that say differently, but no experiments or observations to back these theories up.
.......we're talking about gravitational radiation.......
Can you point me to an actual experiment or observation of such radiation being detected? I'm not talking about somebody's THEORY, even Einstein's, but real scientific measurements here. In the original article it was stated that no gravity waves were detected with a very advanced instrument built especially for this purpose. Not detecting something is often just as important and finding it. The Aether's existence, as postulated back then was disproved by showing its absence.
Measurements and observations must ALWAYS take precedence over *any* theory, no matter how widely held it is or how famous its originators are. Dark matter/energy are another theoretical construct that have never been observed. The Oort cloud as the source of comets is another theoretical fiction that has never been shown to exist. The red shift is well observed and measured, but its cause being theorized as the doppler effect is pure assumption, (belief) just as much as any belief of a religion.
For example, we know by experiment and every day practice, that gamma and x-rays are produced by the acceleration of charges. If the theorized bodies, such as neutron stars and other objects are NOT electrically neutral toward each other, then enormous electric fields could serve to accelerate charged particles, usually electrons, to immense energies. We also know by every day experiments that moving electric charges produce magnetic fields. We also observe that these magnetic fields tend to force these charges to NOT travel in a straight line, thereby releasing synchrotron radiation, ie. gamma rays. These fields also tend to focus these charged currents into narrow beams. You can sometimes see this effect in a neon sign. We also commonly observe that when fast moving charged particles suddenly slam into an obstacle they also produce large quantities of radiation. Could it be that such well known, researched mechanisms might be responsible for these radiation outbursts we observe? Could it be that gravity is not in the least involved in this and that's why we have not observed gravitational waves from this or any other source? If bodies, such as the sun and the planets are not electrically neutral, and there is evidence (solar wind) that they are not, the electric fields and currents around and between them would certainly affect electromagnetic radiation passing through those fields and currents. Thus what is thought to be "gravitational lensing" deflecting electromagnetic radiation, could also be caused by the electric and magnetic fields surrounding highly charged objects, such as the sun, such as in Eddington's observation during the solar eclipse. He observed a deflection of light, but he INTERPRETED that observation as being due to gravity.
(...information has traveled faster than light. Which is not possible....)
Information and its carrier are distinct. If there is a carrier that can go faster than the speed of light, then so can information. It is theorized by no one less that Einstein that gravity too is subject to the speed limit of light. However this has not been EXPERIMENTALLY or observationally verified. Gravity is a very weak force, quite distinct from the other forces of matter. It arises out a still mysterious property of matter we call mass. Until we know what it is about matter that causes it to have this thing we call mass, gravity will not be understood. We do know that both gravity and the electric interaction are long range forces and therefore can and do affect the universe as a whole.
It is NOT science when one makes up theories that have no basis in actual repeated observation or experiment. Einstein's theories have many aspects. Some of these aspects have been experimentally verified to many decimal places of accuracy. Others, such has some of his ideas about gravity have not, at least as far as I know. He did not like quantum science all that much, until experimental evidence piled up. Questioning Einstein is akin to heresy in religion, but I am under the impression that science is different, that it is based on observation and experiments. Maybe I am wrong about that.
..... clocks running slower in higher gravitational fields......
What force governs these clocks? Is it not the electric force that governs atoms? Of course, we know that gravity affects atoms and atomic behavior. That's why light that travels close to the sun gets deflected slightly. Also, if the sun in its entirety is not electrically neutral, any charge it carries could also affect electromagnetic radiation in a very small way. There is evidence that the sun is NOT electrically inactive, by the measured fact of large solar magnetic fields. We know of no source of magnetism apart from the movement of charges.
The motions of heavenly bodies is way too slow against each other to be materially affected by relativity concerns. Yes, your watch runs slower atop Mt. Everest than at sea level but it is a trivially small effect. In equations you not only have to look at the math, but also the relative sizes of the numbers involved. Relativity doesn't change the orbits of planets or galaxies in any amount we'd be able to measure. In the world we actually live in, relativity can be safely ignored in most instances.
....arguing gravity is instant using Newton is pointlessly wrong......
There are very few, if any masses, that give rise to appreciable gravity, that are moving anywhere near fast enough to allow relativity to come into play. Yes, theoretically, there is an effect, but it is trivially small. For all practical purposes, the solar system and the galaxy motions are governed by Newton. Einstein doesn't get into the act until you get near the speed of light. No mass subject to gravity moves very fast compared to light. Also, nobody has ever MEASURED a speed factor for gravity. Maybe gravity is not instant, but just faster than we can measure, just as light speed was so fast it also could not be measured until our technology got good enough. Until somebody actually DOES measure it, I think it is safe and practical to go with Newton and assume that for present purposes, gravity is not subject to time, at least not in our present frame of reference.
(.....Relativity applies everywhere....)
As far as we know it does. However, physicists still have a hard time fitting gravity into the framework of quantum science and the other forces of nature. We know is that mass somehow gives rise to a force we call gravity that accelerates mass. We can measure gravity and time, but don't really know yet what either of these really are and how they fit the puzzle of our universe. BTW, there is no law of physics we know of that demands that the speed of light be constant. That is an assumption we make. It is tied with another assumption that the red shift we observe is due to the doppler effect. Increasingly, data from modern advanced telescopes and space probes puts both of these assumptions on an ever shakier base. If the red shift is due to a fundamental change in the properties of space, as the universe expanded, the red shift would be telling us that the speed of light is much less now than it was when the universe was smaller and denser. There is nothing as constant as change. We have to very carefully examine our uniformitarian assumptions, even if they seem very comforting to us.
....Space (distance) and time are rather intricately linked in Relativy,....
The equations of gravity are simple and do NOT contain a time element.
Force of Gravity = G*(m1*m2)/r^2
where G = gravitational constant, m1 and m2 are the masses of the objects and r= distance between them. There are NO time values, which would imply speed. Electromagnetic equations DO have time values in them. Also, the constant G is a dimensionless number, whereas the "constants" that apply to electromagnetic interactions (c and it inversely related h) have time attached to them. Now the ACCELERATION produced by gravity DOES have a time unit, but gravity itself does not. Thus, the FORCE that two orbiting bodies experience via gravity must be instantaneous, or at least incredibly fast.
Since the orbital speeds are very much less than the speed of light, relativity doesn't enter the picture.
....But reality is Non-Newtonian.....
For the electromagnetic interaction, relativity has been experimentally shown, but gravity is still pretty much a mystery. We know that matter somehow gives rise to an acceleration we call gravity. There is no way to tell the difference between this acceleration due to gravity and the acceleration of matter by some means. There is no experiment you could do inside, if you were sealed into a closed rocket, to tell whether your cabin was being accelerated through space at 32ft/sec/sec or if that cabin was simply parked on the launch pad on earth.
We also know by experiment, that the gravitational interaction is some 36 orders of magnitude smaller than the electric interaction. Two neutron stars or black holes in close proximity, could have way more influence on each other and the radiation emitted, by way of the electric interactions between them, than by gravity.
Sure, the theory of relativity asserts that gravity is also subject to the speed of light, but that part of relativity has never been experimentally verified. Newtonian mechanics mandate that gravity ITSELF not be in any way be impacted by time. Only the ACCELERATION produced by gravity has a time value. Since the planets and galaxies don't move relative to each other at anywhere close to the speed of light, relativity doesn't enter into the picture here.
..... it has been observed that the system loses energy (causing the stars to get closer together) at a rate exactly equal to the predicted production of gravitational waves.......
We measure a rate of energy loss that happens to correlate with the theory of how gravity waves might be generated. So, since when does correlation guarantee causation? Is it possible that the energy loss, even though it correlates with present theory, nevertheless has a different, perhaps yet unknown cause? Maybe there are other forces at work, besides gravity? After all, gravity is the weakest of all known forces by which matter and energy interact.
...It is integral to the equations that model electromagnetic phenomenon.....
True. It is however NOT integral to equations that describe gravity! There is no time value in them. That could mean that gravity is independent of time and therefore speed. Therefore, if someone turned on a gravity generator or suddenly removed a gravity shield, the effects of that should be instantaneous, or at least very fast over large distances. Until Mr. Roemer first measured the speed of light, it too was thought to be instantaneous. Maybe someday the speed of gravity will be measured. If it is, the speed of light will be at snails pace comparatively.
The sun and the center of our galaxy are in gravitational "touch" with each other NOW, not how they were thousands of light years ago.
..... As far as we know, there is no way for information to travel faster than light......
And just WHERE do you get that idea? The speed at which information can travel is limited to the speed of its carrier. If you can find a carrier that travels faster than light and put the information thereon, that information can arrive much faster. What is the speed of gravity? What about the speed of thought? Gravity must be instantaneous or at least very fast. The sun and the earth "feel" each other where they are NOW, not where they were 8 minutes ago. Gravity itself seems to be only dependent on mass and distance. Nowhere does time enter into its operation. Now the equivalent ACCELERATION of gravity does have a time element.
..... It basically means you're assuming that causality exists ......
Why do you jump to that conclusion? Gravity has to work either instantaneously or incredibly fast. The sun holds the earth in place where it is NOW, not where it was eight minutes go. Gravity doesn't involve time, only mass and distance.
.....there is a fundamental and unproved ASSUMPTION in Physics that gravity waves must travel at the speed of light......
If gravity WERE as slow as the speed of light, the sun would have long ago lost its planets and itself would have left the galaxy. The equations for gravity don't have time values. That should tell us something.
....The General Theory of Relativity says they should move at the speed of light......
If gravity is confined to the speed of light, the Sun should have lost its planets long ago. For example, simple Newtonian math tells us that the Sun and Jupiter "KNOW" about each other right NOW or in a very short amount amount of time, not 43 minutes later. the Earth and the Sun "feel" each other's gravity instantaneously, not with an eight minute delay. The sun and the center of our galaxy communicate by gravity without a many light year time delay. Otherwise, the galaxy would fly apart.
Matter and electromagnetic energy have a speed limit, but gravity either doesn't have a limit at all, or it is incredibly high. Gravity equations do not contain any time values, only mass and distance.
.....Normally such bursts arise from well known phenomena,.......
A well known way of generating x-rays and gamma rays is to accelerate fast moving charges, usually electrons. Instead black hole collisions, could it be that immense galactic electric fields accelerate huge quantities of free electrons to stupendous energies? These electric currents then give rise great magnetic fields which force the electrons to emit intense synchrotron radiation which we can detect? We routinely do this sort of thing at places like the Synchrotron Radiation Lab at Stanford. They can generate the most intense gamma radiation bursts made on Earth.
Maybe the fast moving electrons collide with an object, abruptly slowing them down like a target in a cosmic x-ray machine? Bremstrahlung effects like this would not leave any gravitational signature, since there are no large masses, such as black holes involved.
.....comes with a built in monitor that cannot be kept after the end of the macs usefull life........
The useful life and resale value of Macs is considerably higher than a similar aged PC. Check out e-bay for that. I bought my younger daughter a Macbook to replace her G4 iBook so she could also use Windows at her university. I now use her old iBook G4 as a very capable media machine connected to a digital projector and our stereo system in the living room. It plays back DVD's and iTunes material. I gave my 7 year old Titanium G4 Powerbook to a friend of limited means and he is as happy as a lark. He is using its built in S-Video connection with his Sony TV to show movies and photos, as well as mail and web surfing via the built in wireless. His much newer, faster Windows desktop machine has fallen into disuse, gathering dust, despite the fact that the old Mac is rather slow. The PC will not connect to his TV set without added hardware and software.
(.....has space for only one internal hard drive though it is a proper desktop model......)
I have a portable 500G firewire HD which will connect to any Mac. It will transparently boot any of them in case there is a problem and also serves as a backup for the data on all of our Macs and one PC. Being external, it only gets powered on when actually needed, rather than running all the time like a built in drive would. This means it should last a long time. Even though firewire is spec'd slightly slower than USB2.0, in practice it is faster. I have never heard of an external HD setup for PCs that will boot any laptop and also any desktop system. They have system specific setups. I've used this capability to restore damaged file systems on some other people's Macs. Being able to buy a family license for 5 Macs for not much more than one legal copy of Windows XP Professional or Vista, as well as avoiding all activation hassles is no small potatoes either.
I don't go in for games, but everything I've read, Macs don't have many good games available for them. For all other uses, their graphics is more than adequate. My teenage son likes games, so I bought him an x-box for those. He can also run Windows on his Macbook, but he doesn't use it for games. Over the long term, Macs are more economical, even though they cost more to buy initially, than Windows systems.
......That's not even getting into how inefficient it will be.....
Oh yes, it would be more efficient in terms of energy used and less pollution. However most, if not all of these brilliant urban planners who dream up stuff like this don't consider the value of people's time and convenience. In Europe, everything is much closer together than in the US, especially the western parts. There and in the core of the largest US cities transit works pretty well.
Even if it takes X amount of time on transit or the same in a car stuck in traffic, many will opt to still take their car for the door to door comfort and quiet of a modern automobile. In the end, this will only be the equivalent of another tax on motorists which the politicians will be able to spend on purposes having little or nothing to do with transportation.
....to get features that are standard on PCs......
So what features, other than an expansion slot does a "standard" PC have that an iMac or Mac mini doesn't? If you already have a nice monitor and keyboard, get a Mac mini. If you have a valid copy of Windows, the 2.0Ghz duo will run that quite well with a virtualization program at he same time as OSX10.5 in case you have some Windows apps you really need. You can also use the included Bootcamp program to install Windows, just as you would on any PC.
Forget about high graphics games however. Basically you then would have two machines in one. A virus free Mac and a Windows box for all your favorite programs you may already own. You can even add your favorite flavors of Linux to fool around with if you use a virtualization program, such as Parallels 3.0. I've read that anyone moderately skilled with tools should be able to open the mini to install more RAM and a bigger HD.
......management position in any of the algae to biofuel startups......
Sorry, but I am a now retired electronics engineer. I don't know much about bio-fuels.
If I were going into the energy business, I'd try this:
http://hardware.slashdot.org/article.pl?sid=07/12/21/1627206
or this:
http://science.slashdot.org/article.pl?sid=08/01/09/2310232
The printed $1/watt solar panels could certainly help with our energy problems.
Do you really think that "political correctness" in hiring is more important than hiring the right person for a job? If you do, your investors, if any, may be left holding the bag.
.....There is no 'Mind', and it is therefore meaningless to speculate on what that 'Mind' might want.......
You don't KNOW that, but you believe it because you WANT to believe that there is no God. You hope it lets you out of your responsibility to Him as your Creator.
I do respect your decision to reject God. God has given you the freedom to reject Him. He could have made us like a deterministic, highly intelligent computer, but then we would not be capable of love. You know that if suddenly there appeared on you computer screen: "I love you --- (your name)" that someone was messing with that computer and that it means nothing to you. On the other hand if your spouse or child expresses that love, you respond very differently. The computer doesn't have the capability of love. You do, first of all toward your fellow humans and by extension toward God. All this has nothing to do with religion, but how we are all wired. When someone expresses this love by sacrificing his/her life, they are acting against all principles of "the survival of the fittest" as formulated by Darwin.
Maybe, if you live long enough, you'll begin to understand that there is more to life than science can explore and reduce to a mathematical formula.
.....Still makes just as much sense, and is just as believable.......
Indeed true! That's why, at the core, science is just as much based, at the root, on FAITH. Human rules or laws come from human minds. So then what MIND thought up the laws of nature? You can give that Mind any name you wish. Call it evolution maybe even. There is no way science can observe the existence or non-existence of this Mind. Evidently, this Mind doesn't want to be proven, but rather BELIEVED and trusted.
All children tend to believe their parents and other adults they get to know. Only after they have been lied to by someone they initially trusted, especially by someone who hates or dislikes a parent, do they become doubters and distrustful. They may even come to hate their parents, though these may have done an above average job in their parenting.
In Genesis we read about the first parent, God. There too, the kids first trusted their parent. We are told that another entity came and lied to these children of God and they believed the lie. Most of mankind still believes the lie about their Creator. The central idea of this lie is that man is an independent, sovereign creature in no way accountable to or dependent on a higher Power, their Creator and ultimate parent.
Goebbels once said: "If a lie is bold enough, outrageous enough and repeated loud and often enough, then those who believe that lie will believe it to be the truth.
....I'd naturally have to consider it in light of other, more plausible explanations........
It depends on whether you WANT to believe or not. Jesus said that even if someone were to come back from the dead, those kind of people would not believe whatever such a returnee would say. NOTHING can convince someone to believe anything they don't want to believe. Don't confuse me with the facts, my mind is made up.
......There are only three "articles of faith" for a scientist. The first is that everything in the universe can be explained in terms of a set of rules, regardless of the extent to which we know and understand the rules. The second is that these rules apply without exception to everything in the universe. The third is that the rules are unchangeable..........
There are only three "articles of faith" for a Believer. The first is that everything in the universe can be explained in terms of God, regardless of the extent to which we know and understand the Him. The second is that God controls without exception everything in the universe. The third is that the God is unchangeable.
There, changed it slightly for you. I could add that, like human rules, someone made them. Maybe God is the one that made the "rules" that scientists BELIEVE in.
....but still priced well above the entry level models.....
Give only one good reason why Apple should get into the low profit rock bottom profit killing entry level computer business? If you can't afford a shiny brand new Mac, look around on ebay. A two year old G5 will likely be still better than a rock bottom new Windows system.
.....Every other major manufacturer manages to produce a cheap machine.....
Is it so hard to grasp that Apple doesn't build cheap stuff? Is it so hard to figure out that BMW doesn't make cheap cars? If you can't afford a Mac Pro get a cheap Dell. If you can't afford a BMW, a Yugo. A Dell computes (most of the time) and a Yugo will usually get you across town.
.......Does the employer have the right to know if a potential employee is gay? Muslim? A Democrat? A non-vegetarian? .....
:-) ! If one employer feels that a certain drug doesn't affect the job then that employer should be free to hire such a drug using employee. If another employer feels just the opposite, they should be free to reject such a drug user. It should in no case be the government that forces employers either pro or con in that particular issue. Anything that affects a person physiologically, WILL affect their job performance. Even off the job drug use can. Now, an employer may not care about that and therefore should be free to hire a druggie if it is not a safety issue. I certainly would not get on an airplane, if I knew the pilot is a druggie.
You did not read my post very carefully. None of the things you mention above affect job performance in most situations. Probably, a church would not hire a gay or Muslim because such a person would, by definition, have a world view opposed to that of most churches. Some churches might not hire a Democrat
On the other hand, the government SHOULD have a say against job discrimination on grounds that a person cannot change, such as sex, race or national origin etc. Even there, a fire department should not be forced to hire a 90lb woman for a job that might require carrying a 200lb man out of a burning structure. Some common sense and discretion ought to be used in certain situations.
....Don't tell me that you are justifying workplace drug testing on the basis of "productivity"........
Don't tell me that someone using drugs (legal or illegal) is a more desirable, more productive worker than someone who doesn't use or need those? Don't you think that an employer should have the right to know and intelligently choose between a drug user and someone who does not use nor need such things, just as a person has the right to use or not use drugs? Nobody holds a gun to a person's head and forces them to become a druggie or alcoholic. The use of these substances clearly affects a person, both on the job and off the clock. As a person sows, to they shall also reap.