Re:Wait a sec, this story isn't about "dark matter
on
Dark Matter Discovered
·
· Score: 1
Part one: I like cynical people, in general. They tend to question assumptions such as above. My answer: My degree (and interests) = Orbital Mechanics related.
Part two: True. Then there is the tedius point that I was lazy and didn't write 'unknown forms of matter that only interact gravitationally and not in any other way' etc and instead wrote 'Non-baryonic matter'. Which I think we both know is horribly, horribly wrong.
I'm too tired to explain why, and this is slashdot, so nobody cares anyway.
If 'greenhorn' C++ developers can make an app that is even ONE PERCENT faster, then the Java Developers WERE NOT 'highly skilled'. Period. But TWICE as fast? As in, C++ takes 1/2 the time to execute 'x' as the Java version? No way. Not even if we are talking linear algebra code*.
An experienced Java programmer knows you have to memory manage large apps. Yes, Java will *always* use more memory than an equally well written C++ app; however, unless you are working *exclusively* with *huge* arrays, java will be damn near as fast, and often faster than equivilent C++ code. Hell, if those arrays have to be collected in C++, Java will be faster. *UNLESS* you optimize the living crap out of your C++ code and ignore optimizations on your Java code.
I have *plenty* of issues with Java (for instance, who the f*ck decided on a 64MB default max memory space for the JVM?). Speed has always been one of my Java PLUS points.
* A quote for the lazy: "For example, IBM Watson's Ninja project showed that Java can indeed perform BLAS matrix computations up to 90% as fast as optimized Fortran."
You may not be able to "overflow" some data buffer in Java, but you can always write garbage to it.
Erm, the point of overflowing a buffer is to dump executable data into the stack, hopefully somewhere that will get executed. Or to change a value *which is not associated with said buffer*. Obviously if you working with some particular buffer you can overwrite data in it. That hardly matters and cannot be considered a bug.
FWIW I don't agree with Gosling. I don't use.NET and do use Java, but it really is mostly a comfort issue. I don't feel comfortable with MS taking over the world by yet another increment;~)
Since the point of the ability to execute insecure code is to allow for importing of archaic code, I agree with it as a concept. Anyone intentionally coding out of the sandbox with.NET on new code should simply be shot. There are other languages for that kind of thing. If you need low-level access, learn to write real low-level code; use C (or whatever). If you *think* you need low level access, and you don't know C, you don't f*ing need low-level access.
As always, a hasty generalization created for/. on a whim:~)
An interesting thought -- while I 'knew' that I didn't think about it consciously in regard to my post.
The thought: Who says that for a constant subtended angle, area varies with the inverse square of distance? Newton does.
What does Einstein have to say in the matter?
Why, I think he is going to say that area is going to be a function of both the local mass and the time [A = f(m,t)]. Not very rigorous, but you get the idea.
To further the parent's point: A city government has a moral obligation to do 'what is right' for the city. What is right should ideally be defined by a huge number of things, but 'what the masses want' would be high up there.
In this sense, it is easily possible that the masses don't want 'x', but they do want 'y'. And sometimes, doing 'x' will help you get to 'y'. For instance, if you want to grow the income base of your city, you might do well to attract a lot of higher-paying jobs.... Like, maybe, build-out a wireless WAN. Provided that the citizens don't actively NOT WANT 'x', the city government (or perhaps the people, if by vote) should seriously weigh the benifits.
a, but there is no explanation about why the force of gravity should change over vast distances.
YOu gotta admit, though... There really isn't a good explanation of why gravity SHOULDN'T change over vast distances.:~D
F=ma = G*M*m/(r^2) -- 'G' is derived observationally. Only a few hundred years of observation tell us that it is a constant. Only a few dozen of those actually FROM SPACE -- Perhaps a few hundred years more will show that it is proportional to some (presumambly negative) exponent of 'r' (distance). Perhaps not.
I admit to preferring MOND over imaginary matter. However, what I like the most is that the guys have open minds... unlike the typical 'scientist' favoring NB matter -- a bad hypothesis usually treated as sound theory. If NB matter were treated with the caution that MOND is, I would enjoy reading about it. Instead most authors treat it as assumed fact and build upon it. Bah. Excel can curve fit data; doesn't mean I assume a random scatter plot can be modeled by a 4th order equation.
Re:Wait a sec, this story isn't about "dark matter
on
Dark Matter Discovered
·
· Score: 2, Interesting
Because none of it exists within our own solar system. Else it would have played merry games with our orbital calculations, and we would know where to look for it -- up close and personal.
Seriously: We can model the solar system quite well using only the derived* masses of planets to within a few percentage points per thousand years... Yet supposedly the universe has some random form of gravitational energy which accounts for over 80% of the 'mass'. Get real.
Non-baryonic matter is the luminiferous aether of today.
If I'm wrong, great. But the whole theory stinks of hand-waving. Just becuase you don't have a clue doesn't mean you invent some wild theory -- not when there are dozesn of equally (or more) likely, simple explinations.
Every few years somebody finds another few percent of the 'missing' matter. I'm just waiting.... For some good evidence to satisfy my cynacal nature, or for them to get up to about 90% so that I can openly mock the concept.
For now I do admit that, in general, I don't know more about physicsthan the average masters holder therein; I do, however, know a LOT about gravity -- enough to make me question everything about non-baryonic matter anyway.
*It would be incredibly unlikely that we could 'accidentally' account for any matter/mass from the observational methods by which we derived the present, assumed masses for the planets.
Position, mostly. Developers would be able to make cooler games if they knew that they could query the controller for the angle it is being held at.
The price of a gyro system is cheap enough (as witnessed by the Gyration) that it makes little sense to spend as much or more money on a MEMS system and the higher computing power (and battery consumption) that it would entail.
I went to Uni at a very good school for aerospace. Most of the professors used either Matlab (it has its issues, but it isn't Fortran) or FORTRAN (it may be Fortran NOW, but they use FORTRAN;~).
My first exposure to FORTRAN was a project where we were supposed to figure out what section of code needed to be modified to get a wing-lift calculation routine to work as-per-the assignment. Maybe a thousand lines of code in the section we were to focus on, and around 2K lines total. At this point I'd been working with Java in a paid position for about a year, so programming basics caused no issues.
However, I made it to a section something like this (I don't remember the details exactly):
100 if(lots of math = lots more math)
goto 120 110 evenMoreMath 120 ugly code with no comments
If you read through that code it isn't to bad. But think of the entire 70 char limit filled with equations relating to math you don't quite fully understand. The if statement filled two or three lines. It was BAD.
About eighty lines and 4 hours later I found the 'goto 110' line that an experienced FORTRAN user would expect to find after reading that code.
Needless to say, I hate FORTRAN with a passion now. Yes, the language, like any, is not at fault. But, since it is typically used in an engineering or scientific environment, FORTRAN is usually written by people who should never be allowed to program in the first place; people who are at once smart enough to write 4K lines of code using only three letter variable names, and yet somehow stupid enough to actually do it.
IAARS, and have looked into the use of accelerometers for a few different things; armature satellite use, for one. They simply do not have the resolution you need. Gyros WORK, and are insanely accurate over a very wide range. Accelerometers work for large accelerations (> 0.1G is what I found) but not small, or have a very narrow bandwidth -- they either saturate at high acceleration or don't respond to low acceleration.
In game terms, what this generally means is that for the 'Oh crap I am about to wreck' spastic twitch response the controller would respond. For the 'Controlled entrance into a long turn' you would get nothin'.
Another VERY important aspect of gyros is that they can sense orientation as well as acceleration; in fact, a gyro WORKS by sensing displacement over time, where as a MEMs accelerometer works by sensing the voltage generated by a displacement, the displacement being proportional to the acceleration applied, and the displacement only exists while the system is actually undergoing acceleration.
Key point is that you have to integrate to get position for the MEMS, as opposed to HAVING position and HAVING acceleration; both being essentially equally accurate because you are physically measuring them. The gyro simply cannot saturate (in this use!). Even if you exceed the resolution (# of times you sample position per second) of the device, it still 'knows' that it was displaced, say, 30 degrees between position read at time A and position read at time (A + 0.01). If you saturate the MEMS it has no idea where it is. Thus you couldn't use the MEMS controller in something like a flight simulator, where the controller orientation is the orientation of the airplane, or where the orientation of the controller indicates the turning angle of a race car; you would have to have a 'recalibrate' button on the controller, just in case you jerked the controller too hard (or dropped it).
* More accurate re: measurements:
-- The error in the MEMS is caused by the error in the reading of the voltage vs displacement -- The error in the Gyro is from the accuracy of the measurement of position; this is more well known and varies less with environmental factors such as temperature and humidity. Typically going to be easier to have a high read accuracy. -- Both* also have a bit of clock error based on the sampling rate.E.g. if your sample rate is 100Hz, you may really be sampling 99 or 101 times per second. For the gyro this does NOT have anything to do with the position, just the acceleration. --> Gyro acceleration error is proportional to (position error + clock error). There are some error coefficients in there, but they are constants. --> The MEMS acceleration error is proportional to (acceleration error + clock error) Here is the problem with MEMS: --Gyro position error is simply the position error. However: -- MEMS position error is proportional to (acceleration error + clock error)*(# of samples). Ouch.
* You have to remember that there is a derivative of acceleration as well; sampling rate DOES matter for the MEMS.
Mine was 20 dollars. Still a bit of a markup from 6 bucks....
MonsterCable et. al. is a joke, with prices to match. Sure, you can buy complete crap cables; but that has always been true. Never heard of anyone buying 'Monster!!! IDE Cables!!' Or 'MONSTER! Aftermarket SVGA HD15 Cables!!'
let us say that the chance of your home getting struck by lightning is 2% (Thats really, high, but hey).
Let us pretend that the home becomes 4% likely to be struck by lightning after being painted.
Looks like it squared.
Ah! But a percent is a fraction...
so: 0.02^x = 0.04.
x = 2*ln(5)/ln(50) =~ 0.822816
A function can vary at any rate. The probability of an event can vary by any of infinite number of rates, and in general the rate at which any one particular event occuring RIGHT NOW would be essentially chaotic due to all the variables in question (e.g., the chance of your computer exploding at THIS INSTANT depends on the temperature, the humidity, if it is on, the proximity of your glass of orange juice, etc) -- thus usually requiring a piecewise function. Hence, the rate the probability of 'X' happening in 'Y' seconds can be exponential from time 'a' to 'b', linear from b to c, etc.
The function can't increase exponentially forever; but he only referred to two points on the curve.
fun stuff. As to the 3rd derivative of an exponential function... d(d(y^x,x,x) = y^x*ln(y))^2 = The rate of change of the rate of change of the rate of change in probability, e.g. the 4th derivative of a probability curve.;~)
The integral of the curve would have more meaning;~)
Speak and spell was the bomb. It it a cop out for the parents? Yeah, sort of. I mean, as a parent you *could* sit there all day with your kid and pronounce random words for them, and have them spell them back to you.
Or you can make dinner while your kid screws with the damn toy, and has a blast learning. An insideous ploy, you must admit.
I remember being learning on the speak and spell, and the math version also. My sister and I also had alphabet blocks and puzzles, and parents that read. No, not read to US, although they did; but they would read in the evenings. So we both wanted to read also. Which is an affirmation to your comments PalmKiller; we both did respect our parents for precisly the reason you described, and thus wanted to emulate them.
I disagree however that technology does nothing for improving learning. It is only an aid, but it IS an aid. Just like alphabet puzzles and legos, the pen in question is an educational toy; someting that a kid can play with and learn with at the same time. Is Wiki/Digital Encyclopedia) any better for a kid than the paper set of Britanica (aside from the fact that Wiki will probably never fall off the shelf and maim them for life)? Not really. But what about Number Munchers and Word Munchers!! Those were sweet.
Thing about MineSweeper is that if you have to think about it, you won't be any good at all.
I say this as a someone who sucks at minesweeper.
I used to watch my gf play (until it made me sick with shame). She could hold full, normal conversations, minus any form of eye contact, and still beat my record time on large by about, oh, 10 minutes -- she would usually take less than 5 min to beat the large ones. I'd say two, but its been forever and I can't remeber well. When she blew up a mine it was almost always a clicking error.
The cameras would be more robust than a human eye, and could turn off until safe to re-open.
And it isn't like you need to be able to see OUT to land on a commercial jet -- a camera pointing DOWN would tell the pilot all that the instruments can't.
Or just push the 'Land' button. Planes have been landing using autopilot for quite some time now.
True enough. However, I felt the need to point out that a truly static field would not rotate as it compressed. Much like an ice-skater standing on ice with her arms out will not magically begin to spin when she pulls her arms in.
Its just easier to visualize a rock passing by and stirring up motion than a super-nove 200K light-years away doing the same:~)
My very good friend often refers to herself as an astronomer; her degree says astrophysics. Could you kindly explain the difference so I can make her say "I'm an astrophysicist" when people ask?;~)
(She isn't, really; she does have the degree, but she doesn't practice yet -- working on a Phd in a related field.)
On a solar system scale, the spin of the central body plays a large role in this, but it is still a kind of a game of chase-the-tail.
When the whole system is still gas, something starts it spinning -- a simple thing like a star passing nearby gives objects (the gas particles) a bit of angular moment, which is thus transferred to the system as a whole over eons of time through collsions, gravity, magnetic forces, etc.
Now, if a LARGE object passed by in the XY plane, and a SMALL object passed by in the YZ plane, you will end up with a spin *mostly* in the XY plane, but the *WHOLE SYSTEM* will balance out with a single plane of spin somewhere in between.
Eventually the smaller objects become larger objects, which collide less, thus distributing the angular moment less efficiently. There may be one central body spinning in the XY plane, but a few of the large objects can have a wildly different orbital plane. But not many objects will HAVE this wildly different orbital plane, because back when the system was being formed, the angular moment transfer WAS very efficient.
Also, 'circular' orbits, like the earths or mars or Jupiters, are fairly rare on a random scale of things; and if you have a bunch of objects orbiting in different planes with highly ellipical orbits, they have a much higher chance of smacking into each other (or some larger object, like jupiter) than the same object would if it were in a more circular orbit which happened to be in a different plane than that of the central masses spin. Don't forget the time scales in question here!
Now, finally, in systems like that of the Earth and its huge moon, you get tidal interactions; while the moon will never shift in its orbit enough to be in an equatorial orbit, it *does* shift more closely to one every day, thanks to the 'gravity drag' between itself and Earth. Really what is happening is that the Earths spin is accelerated in the direction of the moons travel (really, this is slowing our spin rate down, think acceleration in the physics sense). Earth has already done this to the moon; hence the 'tidal lock' which has the moon presenting the same side to Earth at all times.
Were you to watch the Earth moon system forever, eventually what you would see is two bodies rotating about a central point, both with the axis of spin of each body being parallel to the axis of rotation about said central point (hope you can visualise that!). In reality this won't occur in any amount of time, the influence of the sun, and the fact that the moon would actually leave earths gravitation influence before alignment could occur prevent it. (The orbit of the moon gets larger as it steals earths rotational momentum).
Slashdot Mirror
Part one:
I like cynical people, in general. They tend to question assumptions such as above. My answer:
My degree (and interests) = Orbital Mechanics related.
Part two:
True. Then there is the tedius point that I was lazy and didn't write 'unknown forms of matter that only interact gravitationally and not in any other way' etc and instead wrote 'Non-baryonic matter'. Which I think we both know is horribly, horribly wrong.
I'm too tired to explain why, and this is slashdot, so nobody cares anyway.
I call bullshit.
If 'greenhorn' C++ developers can make an app that is even ONE PERCENT faster, then the Java Developers WERE NOT 'highly skilled'. Period. But TWICE as fast? As in, C++ takes 1/2 the time to execute 'x' as the Java version? No way. Not even if we are talking linear algebra code*.
An experienced Java programmer knows you have to memory manage large apps. Yes, Java will *always* use more memory than an equally well written C++ app; however, unless you are working *exclusively* with *huge* arrays, java will be damn near as fast, and often faster than equivilent C++ code. Hell, if those arrays have to be collected in C++, Java will be faster. *UNLESS* you optimize the living crap out of your C++ code and ignore optimizations on your Java code.
I have *plenty* of issues with Java (for instance, who the f*ck decided on a 64MB default max memory space for the JVM?). Speed has always been one of my Java PLUS points.
* A quote for the lazy:
"For example, IBM Watson's Ninja project showed that Java can indeed perform BLAS matrix computations up to 90% as fast as optimized Fortran."
You may not be able to "overflow" some data buffer in Java, but you can always write garbage to it.
.NET and do use Java, but it really is mostly a comfort issue. I don't feel comfortable with MS taking over the world by yet another increment ;~)
.NET on new code should simply be shot. There are other languages for that kind of thing. If you need low-level access, learn to write real low-level code; use C (or whatever). If you *think* you need low level access, and you don't know C, you don't f*ing need low-level access.
/. on a whim :~)
Erm, the point of overflowing a buffer is to dump executable data into the stack, hopefully somewhere that will get executed. Or to change a value *which is not associated with said buffer*. Obviously if you working with some particular buffer you can overwrite data in it. That hardly matters and cannot be considered a bug.
FWIW I don't agree with Gosling. I don't use
Since the point of the ability to execute insecure code is to allow for importing of archaic code, I agree with it as a concept. Anyone intentionally coding out of the sandbox with
As always, a hasty generalization created for
Cheers
An interesting thought -- while I 'knew' that I didn't think about it consciously in regard to my post.
The thought: Who says that for a constant subtended angle, area varies with the inverse square of distance? Newton does.
What does Einstein have to say in the matter?
Why, I think he is going to say that area is going to be a function of both the local mass and the time [A = f(m,t)]. Not very rigorous, but you get the idea.
My head hurts now.
To further the parent's point: A city government has a moral obligation to do 'what is right' for the city. What is right should ideally be defined by a huge number of things, but 'what the masses want' would be high up there.
In this sense, it is easily possible that the masses don't want 'x', but they do want 'y'. And sometimes, doing 'x' will help you get to 'y'. For instance, if you want to grow the income base of your city, you might do well to attract a lot of higher-paying jobs.... Like, maybe, build-out a wireless WAN. Provided that the citizens don't actively NOT WANT 'x', the city government (or perhaps the people, if by vote) should seriously weigh the benifits.
just my 2 cents
Actually, you are wrong. Or you are right. Or you would be wrong if it were 5 years ago. Or.. OR AHHHHH
Dark matter was originally used to refer to matter that was not yet accounted for. Non-baryonic matter being a subset of Dark Matter.
The issue has been beaten to death so badly by poor authors that 'Dark Matter' is becoming assumed to refer to NB matter.
It is hard to argue that you are wrong, but equally hard to win an argument saying you are correct.
a, but there is no explanation about why the force of gravity should change over vast distances.
:~D
YOu gotta admit, though... There really isn't a good explanation of why gravity SHOULDN'T change over vast distances.
F=ma = G*M*m/(r^2) -- 'G' is derived observationally. Only a few hundred years of observation tell us that it is a constant. Only a few dozen of those actually FROM SPACE -- Perhaps a few hundred years more will show that it is proportional to some (presumambly negative) exponent of 'r' (distance). Perhaps not.
I admit to preferring MOND over imaginary matter. However, what I like the most is that the guys have open minds... unlike the typical 'scientist' favoring NB matter -- a bad hypothesis usually treated as sound theory. If NB matter were treated with the caution that MOND is, I would enjoy reading about it. Instead most authors treat it as assumed fact and build upon it. Bah. Excel can curve fit data; doesn't mean I assume a random scatter plot can be modeled by a 4th order equation.
Because none of it exists within our own solar system. Else it would have played merry games with our orbital calculations, and we would know where to look for it -- up close and personal.
Seriously: We can model the solar system quite well using only the derived* masses of planets to within a few percentage points per thousand years... Yet supposedly the universe has some random form of gravitational energy which accounts for over 80% of the 'mass'. Get real.
Non-baryonic matter is the luminiferous aether of today.
If I'm wrong, great. But the whole theory stinks of hand-waving. Just becuase you don't have a clue doesn't mean you invent some wild theory -- not when there are dozesn of equally (or more) likely, simple explinations.
Every few years somebody finds another few percent of the 'missing' matter. I'm just waiting.... For some good evidence to satisfy my cynacal nature, or for them to get up to about 90% so that I can openly mock the concept.
For now I do admit that, in general, I don't know more about physicsthan the average masters holder therein; I do, however, know a LOT about gravity -- enough to make me question everything about non-baryonic matter anyway.
*It would be incredibly unlikely that we could 'accidentally' account for any matter/mass from the observational methods by which we derived the present, assumed masses for the planets.
I haven't followed laptops for a while, and surprised to see that resoltions aren't improving.
They won't improve until you see vector graphics and fonts in the primary OS.
Guess who we should be lighting the fire under?
(god I love euphemisms that can be taken literally)
Position, mostly. Developers would be able to make cooler games if they knew that they could query the controller for the angle it is being held at.
The price of a gyro system is cheap enough (as witnessed by the Gyration) that it makes little sense to spend as much or more money on a MEMS system and the higher computing power (and battery consumption) that it would entail.
Or so I believe.
I went to Uni at a very good school for aerospace. Most of the professors used either Matlab (it has its issues, but it isn't Fortran) or FORTRAN (it may be Fortran NOW, but they use FORTRAN;~).
My first exposure to FORTRAN was a project where we were supposed to figure out what section of code needed to be modified to get a wing-lift calculation routine to work as-per-the assignment. Maybe a thousand lines of code in the section we were to focus on, and around 2K lines total. At this point I'd been working with Java in a paid position for about a year, so programming basics caused no issues.
However, I made it to a section something like this (I don't remember the details exactly):
100 if(lots of math = lots more math)
goto 120
110 evenMoreMath
120 ugly code with no comments
If you read through that code it isn't to bad. But think of the entire 70 char limit filled with equations relating to math you don't quite fully understand. The if statement filled two or three lines. It was BAD.
About eighty lines and 4 hours later I found the 'goto 110' line that an experienced FORTRAN user would expect to find after reading that code.
Needless to say, I hate FORTRAN with a passion now. Yes, the language, like any, is not at fault. But, since it is typically used in an engineering or scientific environment, FORTRAN is usually written by people who should never be allowed to program in the first place; people who are at once smart enough to write 4K lines of code using only three letter variable names, and yet somehow stupid enough to actually do it.
haha. Please ignore my horrible typos: for one, I have never worked on an armature satellite. Only an amateur one.
IAARS, and have looked into the use of accelerometers for a few different things; armature satellite use, for one. They simply do not have the resolution you need. Gyros WORK, and are insanely accurate over a very wide range. Accelerometers work for large accelerations (> 0.1G is what I found) but not small, or have a very narrow bandwidth -- they either saturate at high acceleration or don't respond to low acceleration.
In game terms, what this generally means is that for the 'Oh crap I am about to wreck' spastic twitch response the controller would respond. For the 'Controlled entrance into a long turn' you would get nothin'.
Another VERY important aspect of gyros is that they can sense orientation as well as acceleration; in fact, a gyro WORKS by sensing displacement over time, where as a MEMs accelerometer works by sensing the voltage generated by a displacement, the displacement being proportional to the acceleration applied, and the displacement only exists while the system is actually undergoing acceleration.
Key point is that you have to integrate to get position for the MEMS, as opposed to HAVING position and HAVING acceleration; both being essentially equally accurate because you are physically measuring them. The gyro simply cannot saturate (in this use!). Even if you exceed the resolution (# of times you sample position per second) of the device, it still 'knows' that it was displaced, say, 30 degrees between position read at time A and position read at time (A + 0.01). If you saturate the MEMS it has no idea where it is. Thus you couldn't use the MEMS controller in something like a flight simulator, where the controller orientation is the orientation of the airplane, or where the orientation of the controller indicates the turning angle of a race car; you would have to have a 'recalibrate' button on the controller, just in case you jerked the controller too hard (or dropped it).
* More accurate re: measurements:
-- The error in the MEMS is caused by the error in the reading of the voltage vs displacement
-- The error in the Gyro is from the accuracy of the measurement of position; this is more well known and varies less with environmental factors such as temperature and humidity. Typically going to be easier to have a high read accuracy.
-- Both* also have a bit of clock error based on the sampling rate.E.g. if your sample rate is 100Hz, you may really be sampling 99 or 101 times per second. For the gyro this does NOT have anything to do with the position, just the acceleration.
--> Gyro acceleration error is proportional to (position error + clock error). There are some error coefficients in there, but they are constants.
--> The MEMS acceleration error is proportional to (acceleration error + clock error)
Here is the problem with MEMS:
--Gyro position error is simply the position error. However:
-- MEMS position error is proportional to (acceleration error + clock error)*(# of samples). Ouch.
* You have to remember that there is a derivative of acceleration as well; sampling rate DOES matter for the MEMS.
Because everything art-related has more value when you are dead. ;~)
Mine was 20 dollars. Still a bit of a markup from 6 bucks....
MonsterCable et. al. is a joke, with prices to match. Sure, you can buy complete crap cables; but that has always been true. Never heard of anyone buying 'Monster!!! IDE Cables!!' Or 'MONSTER! Aftermarket SVGA HD15 Cables!!'
Ugh. Marketing makes me sick.
omfg I've never laughed so hard at a /. post in my life.
let us say that the chance of your home getting struck by lightning is 2% (Thats really, high, but hey).
;~)
;~)
Let us pretend that the home becomes 4% likely to be struck by lightning after being painted.
Looks like it squared.
Ah! But a percent is a fraction...
so: 0.02^x = 0.04.
x = 2*ln(5)/ln(50) =~ 0.822816
A function can vary at any rate. The probability of an event can vary by any of infinite number of rates, and in general the rate at which any one particular event occuring RIGHT NOW would be essentially chaotic due to all the variables in question (e.g., the chance of your computer exploding at THIS INSTANT depends on the temperature, the humidity, if it is on, the proximity of your glass of orange juice, etc) -- thus usually requiring a piecewise function. Hence, the rate the probability of 'X' happening in 'Y' seconds can be exponential from time 'a' to 'b', linear from b to c, etc.
The function can't increase exponentially forever; but he only referred to two points on the curve.
fun stuff. As to the 3rd derivative of an exponential function... d(d(y^x,x,x) = y^x*ln(y))^2 = The rate of change of the rate of change of the rate of change in probability, e.g. the 4th derivative of a probability curve.
The integral of the curve would have more meaning
Speak and spell was the bomb. It it a cop out for the parents? Yeah, sort of. I mean, as a parent you *could* sit there all day with your kid and pronounce random words for them, and have them spell them back to you.
Or you can make dinner while your kid screws with the damn toy, and has a blast learning. An insideous ploy, you must admit.
I remember being learning on the speak and spell, and the math version also. My sister and I also had alphabet blocks and puzzles, and parents that read. No, not read to US, although they did; but they would read in the evenings. So we both wanted to read also. Which is an affirmation to your comments PalmKiller; we both did respect our parents for precisly the reason you described, and thus wanted to emulate them.
I disagree however that technology does nothing for improving learning. It is only an aid, but it IS an aid. Just like alphabet puzzles and legos, the pen in question is an educational toy; someting that a kid can play with and learn with at the same time. Is Wiki/Digital Encyclopedia) any better for a kid than the paper set of Britanica (aside from the fact that Wiki will probably never fall off the shelf and maim them for life)? Not really. But what about Number Munchers and Word Munchers!! Those were sweet.
Thing about MineSweeper is that if you have to think about it, you won't be any good at all.
I say this as a someone who sucks at minesweeper.
I used to watch my gf play (until it made me sick with shame). She could hold full, normal conversations, minus any form of eye contact, and still beat my record time on large by about, oh, 10 minutes -- she would usually take less than 5 min to beat the large ones. I'd say two, but its been forever and I can't remeber well. When she blew up a mine it was almost always a clicking error.
100% subconcious.
The cameras would be more robust than a human eye, and could turn off until safe to re-open.
And it isn't like you need to be able to see OUT to land on a commercial jet -- a camera pointing DOWN would tell the pilot all that the instruments can't.
Or just push the 'Land' button. Planes have been landing using autopilot for quite some time now.
He had a 100 dollar Fiber testing laser.
True enough. However, I felt the need to point out that a truly static field would not rotate as it compressed. Much like an ice-skater standing on ice with her arms out will not magically begin to spin when she pulls her arms in.
:~)
Its just easier to visualize a rock passing by and stirring up motion than a super-nove 200K light-years away doing the same
Cheers,
My very good friend often refers to herself as an astronomer; her degree says astrophysics. Could you kindly explain the difference so I can make her say "I'm an astrophysicist" when people ask? ;~)
(She isn't, really; she does have the degree, but she doesn't practice yet -- working on a Phd in a related field.)
Slip a magnet next to his wallet.... see what he says the next class session.....
On a solar system scale, the spin of the central body plays a large role in this, but it is still a kind of a game of chase-the-tail.
When the whole system is still gas, something starts it spinning -- a simple thing like a star passing nearby gives objects (the gas particles) a bit of angular moment, which is thus transferred to the system as a whole over eons of time through collsions, gravity, magnetic forces, etc.
Now, if a LARGE object passed by in the XY plane, and a SMALL object passed by in the YZ plane, you will end up with a spin *mostly* in the XY plane, but the *WHOLE SYSTEM* will balance out with a single plane of spin somewhere in between.
Eventually the smaller objects become larger objects, which collide less, thus distributing the angular moment less efficiently. There may be one central body spinning in the XY plane, but a few of the large objects can have a wildly different orbital plane. But not many objects will HAVE this wildly different orbital plane, because back when the system was being formed, the angular moment transfer WAS very efficient.
Also, 'circular' orbits, like the earths or mars or Jupiters, are fairly rare on a random scale of things; and if you have a bunch of objects orbiting in different planes with highly ellipical orbits, they have a much higher chance of smacking into each other (or some larger object, like jupiter) than the same object would if it were in a more circular orbit which happened to be in a different plane than that of the central masses spin. Don't forget the time scales in question here!
Now, finally, in systems like that of the Earth and its huge moon, you get tidal interactions; while the moon will never shift in its orbit enough to be in an equatorial orbit, it *does* shift more closely to one every day, thanks to the 'gravity drag' between itself and Earth. Really what is happening is that the Earths spin is accelerated in the direction of the moons travel (really, this is slowing our spin rate down, think acceleration in the physics sense). Earth has already done this to the moon; hence the 'tidal lock' which has the moon presenting the same side to Earth at all times.
Were you to watch the Earth moon system forever, eventually what you would see is two bodies rotating about a central point, both with the axis of spin of each body being parallel to the axis of rotation about said central point (hope you can visualise that!). In reality this won't occur in any amount of time, the influence of the sun, and the fact that the moon would actually leave earths gravitation influence before alignment could occur prevent it. (The orbit of the moon gets larger as it steals earths rotational momentum).
That was fun.