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This first part is perfectly correct. This part isn't right. By this logic, the tidal force would make you weigh more when the Moon is directly underfoot. It doesn't. The tidal force from the Moon when the Moon is directly underfoot is nearly equal in magnitude to that when the Moon is directly overhead. However, it is directed away from the center of the Earth in both cases. The tidal force from the Moon does make you a tad heavier when the Moon is on the horizon, in which case the magnitude is about half that when the Moon is directly overhead or directly underfoot. The tidal acceleration due to the Moon at some point on the surface of the Earth is the difference between the gravitational acceleration toward the Moon at the point in question and the gravitational acceleration of the Earth as a whole toward the Moon.

Try it. What does inverting the digits and adding one do to 1111 1111 1000 0000 ?

Tides? Come off it! Think about it for just a second. Tides are a meter high, more or less. The equatorial bulge is 20 kilometers high. insane_alien and swansont are closer to the mark -- maybe. You two didn't look at the whole picture. The ice piled on top of Greenland and Antarctica presses the rock on which that ice lies deeper into the Earth. As that ice melts the land rises; this is called post-glacial rebound. As rock is about 3 times as dense as water, melting of the ice might mean that mass is transferred poleward rather than toward the equator. Another effect that might transfer mass poleward is the heating of the oceans. The southern Pacific has a lot of open water, as does the Arctic Ocean (the Arctic ice cap is still water). Heating of the oceans will expand the ocean volume, so this too might transfer mass poleward. On the other hand, global warming will raise the height of the troposphere, and this effect will be greatest at the equator. So what do scientists have to say about this? Let's ask a few climatologists. Landerer, F. W., J. H. Jungclaus, and J. Marotzke (2007), Ocean bottom pressure changes lead to a decreasing length-of-day in a warming climate, Geophys. Res. Lett., 34, L06307, doi:10.1029/2006GL029106. http://www.agu.org/pubs/crossref/2007/2006GL029106.shtml Thus, ocean warming and the ensuing mass redistribution change the length-of-day by −0.12 ms within 200 years, demonstrating that the oceans are capable of exciting nontidal length-of-day changes on decadal and longer timescales. de Viron, O., V. Dehant, H. Goosse, and M. Crucifix (2002), Effect of global warming on the length-of-day, Geophys. Res. Lett., 29(7), 1146, doi:10.1029/2001GL013672. http://www.agu.org/pubs/crossref/2002/2001GL013672.shtml we reach the following conclusions: (1) the models globally agree to an increase of the LOD of the order of 1 μs/year, (2) the effect is mostly associated with an increase of the mean zonal wind, of which about one third is compensated by a change in mass repartition. Well, that didn't help much. The day will get shorter by 120 microseconds in a couple of hundred years. But then again, it might get longer by a microsecond. The affect will be small. We've already had some global warming. What does the data say? This plot show variations in excess length of day from 1966 to 2001. (Length of day is the length of one day, UT1-R. Excess length of day is length of day less 86400 seconds TAI.) Source: http://www.iers.org/images/figc.png The data don't say much. The recent smoothed trend is that length of day is shortening. However, the longer trend is all over the place, including a multi-decadal oscillation that nobody knows the cause of (yet). The looong term effect, the transfer of angular momentum from the Earth's rotation to the Moon's orbit, can't be seen on this graph. It's too short a time span. To see that you would need a graph that spans a couple hundred years or so. A couple final points. Those season variations are one example of how climate affects the Earth's rotation. The Earth has more land in the Northern Hemisphere, more water in the Southern Hemisphere. Snow accumulates on the land during Northern Hemisphere winter, transferring mass poleward, and then melts, transferring mass toward the equator. Another example: Look at the residual oscillation plot. There is a huge spike in 1982-83. That is the worst El Nino on record. Changes in climate most certainly can have an effect on Earth rotation. Finally, I'll put words in Mooey's mouth. "Hey DH! I thought you said tides are tiny. What is that noisy-looking graph labeled 'Effects of zonal tides, periods up to 35 days'?" Fair point. Firstly, that's basically a zero mean noise signal. Second, those are zonal tides. The Moon raises tides in the Earth itself as well as in the oceans. The Earth tides, rather than the ocean tides, are the primary component of these zonal tides.

Nimit, you missed the point. I suggested you read about transformers because transformers are an application of mutual inductance. You ignored mutual inductance to arrive at your paradox. Do you think that mutual inductance goes away just because you are using direct current?

newphysics, You want us to open a Word document posted by someone with one whole post under behind their name? Do you think we're insane? Besides, this has nothing to do with the speed of gravity.

That's an outer product. Now what are you going to do with it? (In other words, what are you really asking in this thread?)

So? Do you think you have found a flaw in the laws of physics? Hint: You haven't. Google the phrase "dynamic pressure" to see why.

'Nuff said?

Oh please, enough with the hyperbole, Pangloss! Five years? It was only 3 1/2. So, 1000 people for 3.5 years, and "over 800,000 lines of code." (Wikipedia reports 900,000 lines of code.) Take the average, more-or-less: Call it 840,000 lines of code in Grand Theft Auto IV. What does that equate to? Let's say that with holidays, sick days, and vacation time an average person works 240 days a year (52 weeks less 4 weeks times 5 days per week). Doing the math, [math]\frac {840,000\,\text{lines of code}}{1000\, \text{people}*3.5\,\text{years}*240\,\text{working days/year}}[/math] Drum roll please: One line of code per person per day. That is typical of big projects, and that, in a nutshell, exemplifies the difference between big projects and small ones.

He gave one a while ago, the wikipedia page. The interesting thing about that page is the associated discussion page. The wiki editors are questioning the validity of the page. Should it stay (neat stuff) or should it go (pseudoscience). Per the discussion page, it's pseudoscience.

Not quite the same thing, though. The cross product is a vector (well, almost; it's a pseudo-vector); the wedge product is not a vector, period. The cross product as such can be defined in R3 and R7 only. Think of it as an offshoot of the imaginary part of the quaternion and octonion product. Why not R15, R31, ...? The sedenions aren't even alternative. While the Cayley–Dickson construction goes on forever, after a few iterations (reals, complex numbers, quaternions, octonions) its pretty much useless.

The cross product is defined for 3-vectors period. It does not generalize directly. The tensor product has the same constraints as the inner product. Dimensions have to match.

It's not defined.

The general form for relativistic velocity addition is [math] \mathbf u + \mathbf v = \frac {\mathbf u + \mathbf v_{\parallel} + \sqrt{1-u^2/c^2}\,\mathbf v_{\perp}} {1+\mathbf u\cdot\mathbf v/c^2} [/math] where [math]\mathbf v_{\parallel}[/math] and [math]\mathbf v_{\perp}[/math] are the components of [math]\mathbf v[/math] parallel and perpendicular to [math]\mathbf u[/math]. This obviously commutes only when the two velocities are parallel. When they aren't parallel you get Thomas precession.

"Many" ships disappear in the Bermuda triangle for a very simple reason: Many, many ships go through it. The key question is not the number of ships that disappear, but rather, the percentage of ships that disappear there. In that light there is nothing there. The shipping insurance industry knows what waters are abnormally dangerous and charge premiums for ships that sail through such waters. You want to sail a ship through the Gulf of Aden? Be prepared to pay a piracy premium. Near Antarctica? There's an emergency evacuation premium for that. The premium charge for sailing through the Bermuda triangle: nothing.

Sorry to be blunt, but that one word pretty much sums up how I would classify your writing. Let's take a look. No, we don't. Read up on mutual inductance. I also suggest reading up on transformers.

You got the point. Europeans still exist because not all of them migrated to North America. Only a tiny fraction did that. The rest lived on as Europeans. Some but not all Asians similarly migrated to the Americas 15 thousand years ago or so. When a sub-population splits off from a large population that sub-population and its parent population can follow separate evolutionary paths. The sub-population evolves into something else. The common ancestor of the apes and monkeys was most likely something different from apes and monkeys. We don't know what that common ancestor looked like; it happened too long ago and the fossil record is too sparse. Whatever it was, its descendants followed different paths, some becoming monkeys, some apes. In comparison, the last common ancestor of humans and other apes was an ape. That pre-human ape came out of the forest. Just because our ancestor came out of the forest did not force all apes to do so. Most stayed in the forests where their descendants still live to this day.

You have been duped by a false argument, forufes. A question: They say most North Americans are descended from Europeans. By why are Europeans still alive then? If you can answer this question, you will have the answer to why apes and monkeys are still alive now.

Scientists assess the mass of the Sun by observing how things orbit the Sun. This gives the product of solar mass and the gravitational constant. Note well: The Sun's composition does not come into play in determining the solar gravitational coefficient. All it takes is observing planetary motion. The solar mass is simply the solar gravitational coefficient divided by the gravitational constant. The Sun's composition does not come into play in determining G, either. Bottom line: What we know of the Sun's mass has nothing to do with what we know of the stuff that forms the Sun. You have not found the source of dark matter. ====================== That's very nice, Widdekind. This of course has nothing to do with Andromeda and the Milky Way. They did not start at rest with respect to one another at essentially infinite distance.

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Did you read my post? There is a huge amount of stuff in between. How to write real programs, as opposed to toy ones, is essentially what software engineering is all about.

I have to disagree, Jill. "Real" programs add a several dimensions that either do not exist or are trivially small in small programs. Requirements: For a small program, there might be but one requirement that can be written in the form of a sentence or two. The hacker's mantra, "we don't need no stinkin' requirements" has sunk many large programs. Keeping track of what is required of a project and ensuring that the project truly satisfies all things required of it takes on ever more importance as the project grows in size. Design: The same goes for design. In a large project, requirements often map to multiple design components, and a design component can (partially) satisfy multiple requirements. What is a simple one-to-one relationship in a small project can easily become a many-to-many nightmare if the requirements and design are not well thought out. Testing: Cap'n talked about Firefox. Something like Firefox needs a specialized team of testers, people who are good at poking holes. Get something really wrong in a small program and you have at worst made the user push the computer's restart button. Get something really wrong in something like Firefox and the user has just leaked state secrets to their enemy. Testers are of a different mindset than developers. In my experience, really good testers are often incredibly lousy developers, and vice-versa. Documentation: Someone needs to say how the big monster program works, and that someone is definitely not the developer. Architecture: Someone needs to see the big picture and ensure that the project moves forward. A small program does not require a system architect. A big project dies without one. Management: Anarchy works great for a team of one. It works fairly good for a team of two or three, OK for four or five. Beyond that, someone needs to be in charge. In real projects, some people find other jobs, some people retire, some people get promoted. How do you keep the team as a whole moving along and properly staffed?

I give up.

The short answer is, how the speed of light is not a part of the definition of how we measure time. I am having a very hard time understanding why you cannot, at least temporarily, just accept those premises to be true. Doing so is a standard practice in law, logic, mathematics, science, and even the movies. For example, proof by contradiction in mathematics works by temporarily assuming a premise is true but then showing that this leads to a contradiction. The only way to arrive at the contradiction is to first accept the premise as true. Movies: If you cannot suspend your disbelief it is very hard to enjoy any movie. You just suspend your disbelief and go with it. Granted, some movies, like the worst SF movie of all times, The Matrix, make it very hard to suspend ones disbelief. The premise at hand isn't anything like The Matrix. Where in "the second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom" do you see any reference to the speed of light? Compare this to "the metre is the length of the path travelled by light in vacuum during a time interval of 1⁄299,792,458 of a second". The reference to the speed of light here is very clear. How we measure time has nothing directly to do with the speed of light. How we measure distance has everything to do with the speed of light.

No. You cannot assume that in general and you must not assume that in this particular case. Once again, one item at a time Premise: There exists some deeper, truer definition of distance than our current speed-of-light based definition. Premise: Using this deeper definition of distance the speed of light changes over time. Consequent: The time it takes light to traverse a constant distance (constant in terms of this better definition of distance) will change over time. Consequent: The distance as measured by our current (presumably faulty) definition of distance will change over time. Do you see that the two consequents are an immediate result of the two premises?