Earth accelerates nearby objects toward it. From your perspective on the surface, the Earth accelerates your plumb bob "down".
Acceleration is change in rate of change of position over time.
Yep. And the Earth's gravity *is* 9.8m/s2 of acceleration on all particles. The fact that other forces may be withholding the particles from falling (e.g. our plumb bob is hanging from the ceiling) does not mean that they are not accelerating. As I said, a water bottle rocket may be made to hang in the air contrary to gravity by tying a string to the end, but it is still accelerating.
In the middle of space, with an equal gravitaional force from all directions, in a ship accelerating at 1G, two plumb bobs hanging side by side will hang parallel.
You're using one of the biggest no-nos of math. You're mixing polar coordinates with cartesian coordinates. The plumb bobs will tend toward the center of the gravity well. The gravity well pulls from a spherical region around it. (Polar coordinates) A rocket ship applies equal force across a surface area, thus has cartesian coordinates. In order to decides if the two are equivalent, you have to apply math to cancel out the polar coordinates.
Why does everyone keep talking about planets?! I didn't mention planets. I'm talking about space-faring races. These space travelers with similar frames of reference could easily continue conflicts for millions of our years.
As for supply replenishment, it doesn't matter as long as you decelerate for only a short period of time. e.g. Two ships are traveling side by side at 99.99% c. As they pass near a solar system one suddenly disappears for a second or two, then reappears from behind with new weapons, ore, food, and men. In reality, the ship that disappeared has been gone for a year, but thanks to relativity it's able to rejoin the battle with no significant loss in time.
In my living room, the bobs wont be parallel, but on the ship they will be.
The Earth is curved. Your plumb bobs will attempt to seek the center of the gravitational distortion. Thus they will not be exactly parallel. Of course, things get a little dicey the closer you get to the ground. Because every particle pulls with the same gravitational "weight" as all other particles, your results will start to get screwy. Instead of having one gravitational vector, you're going to have to start calculating for the diagonal pull of other particles. And if you go underground, you'll be pulled up, down, left, and right simultaneously. Unless you go very, very deep, you will still perceive down as down, but you may find yourself getting a bit lighter as time goes by.
I want to use two plumb bobs and the results disprove your assertion. There is an obvious measurable difference in the behaviour of the pairs plumb bobs under acceleration versus a pair of plumb bobs in gravity. Why is my experiment not valid?
Get off of Earth. Earth has gravity, therefore accelerates DOWN. So moving inside a train causes your plumb bob to point in a direction that is a sum of the two vectors. i.e. diagonal. Once you are outside of the influence of gravity fields, a rocket accelerating at 1 G would work and feel just like standing on a planet. "Up" would be the nose, "Down" would be the engines.
Oh, since my plumb bobs are unpowered, they don't attempt to accelerate toward anything.
Want to bet? Hold your plumb bob up in the air by its string. It's pointing toward the ground, right? Now let go of it. If it didn't accelerate, it should stay still. (In fact, this is exactly what would happen in deep space.) Instead, your plumb bob accelerates at 9.8 m/s2. By the time it hits the floor, it will be going significantly faster than it was when you were holding it.
The reason why the plumb bob didn't go anywhere while you where holding it was because it has insufficient acceleration to overcome its captivity. e.g. It's like tying a string to the end of a water bottle rocket. The rocket will attempt to accelerate upwards, but it will be held taught at the length of the string.
To steal from an old song, "free your mind, and the rest will follow";-)
How is this bad? This is one of the cool things about relativistic travel. One of the bigger challenges we're facing right now is keeping people alive long enough to reach their destination. The good news is, if we travel at (or approach) c, this becomes less of a problem.
It's not cool to be forever stuck in time. Actually, it could kind of suck. Relativistic effects, OTOH, tend to suck for those who are planet-bound. They could send a spaceship out to explore the Universe, but it wouldn't be back until long after civilization has fallen and our Sun has gone cold. Under Newtonian physics, our intrepid space travelers would have been able to reach other planets super-fast to both them and people on Earth. Einstein kind of pokes a hole in that idea and said that relativistic travel over extreme distances means that you'll never again see your friends, family, and possibly even the human race.
I keep hearing this, but if you hang to plumb bobs near any mass, they don't hang parallel. Hang two plumb bobs in an accelerating ship and they do. Doesn't appear "==" to me.
Attach a plumb bob to the inside of the nose of a rocket. Now accelerate at 1 G of acceleration. What happens? The plumb bob "hangs" toward the back of the rocket. If we build decks parallel to the engines of the craft, our plumb bob will be perpendicular to the floor. Now hang a plumb bob in your home. Is it perpendicular to the floor?
You see, your plumb bob is attempting to accelerate toward the mass. Thus gravity == acceleration.
Now, I'd like to also point out that there is no real reason why we can't violate causality, causality is in fact highly overrated. People always tell the metaphorical story about someone going back in time to kill his father, but they never really think about it. Quantum uncertainty indicates that each time you go back the result will be a little bit different, so there is no such thing as an infinite loop (it must break 'eventually' because quantum uncertainty will cause you to burst into flame or get hit by a bus or whatever). So, go back, kill your father, don't exist, don't go back (because you don't exist), nobody kills your father, so you exist, so you go back......get hit by a bus, and there we have it, the time line is correct again.
At the risk of getting extremely theoretical here, I'd like to point out that an extra dimension of time would solve this issue. Einstein showed that we could perceive the fourth dimension by observing the rest of the Universe while traveling at a very different 3D speed in relation to it. To a space traveler, this would become a very intuitive thing.
But how would we see two dimensions of time? Well, Quantum mechanics states that instead of true cause and effect, we have all possible events at the same time. If there were any way to perceive that extra dimension, it would be as decisions/random events splitting the timeline. Each event in the universe would give the timeline a velocity into the fifth dimension. Thus timelines would exist were you did kill your grandfather and where you didn't. Causality is intact because you simply obtained a different fifth dimensional velocity by killing your grandfather.
The difficulty is in attempting to define vectors for such a dimension. If it did exist, how might one achieve a perpendicular trajectory in relation to the fourth dimension? If one did achieve a perpendicular trajectory, what would be the results? Is there any measurable thing in the universe that already "slides" perpendicular to the fourth dimension?
These are questions that it may take another Einstein to answer. I wonder if anyone's attempted any equations for this?
Maybe it's the other way around -- a hard speed-of-light barrier essentially makes interstellar war on any scale impractical.
Poppycock! If you had colonies/armies that always traveled at high percentages of c, then they'd all be within similar enough frames of reference that they'd be able to easily carry out wars. To everyone on a "slow" planet, a war would take anywhere from hundreds to millions of years, but to the factions fighting it's all happening within real-time.
When Kepler figured out the planetary orbits, he envisioned invisible brooms sweeping the planets towards the sun. When I read "gravity is just curved spacetime" I think of Kepler's brooms as they both seem to say about as much.
Think more like a bowling ball on a trampoline. The bowling ball will "warp" the trampoline, and objects placed on the trampoline will fall toward it.
As for planetary motion, I'm sure you've seen those funnels that you put coins in. The coin spins round and round. Friction eventually slows it down enough to fall toward the center. If your coin was in a vacuum and had sufficient velocity, it could keep going around the center forever. (e.g. The Earth keeps "missing" the Sun)
Just how does mass warp space? How does space know the mass is around?
We don't know the former yet. Space knows mass is around, because at a quantum level matter and energy are inbalances in the vacuum. "Empty" space is really a bunch of wild waves called "quantum foam" that all cancel each other out.
What particle is gravity's carrier?
Gravitons are only theoretical. At this point it looks like they don't exist. In other words, gravity waves are perpetrated in a vacuum instead of by a particle like the strong force's gluon.
If there is a gravity particle, how come planets don't speed up as they plow into them orbiting the sun?
If a planet heads toward the Sun (not a good thing) it *will* speed up. The trick is that a stable orbit implies having *just enough* speed to keep missing the object.
And how come it gets to escape black holes but no other particles can come out and play?
Because there's no particle. It's the nature of space-time.:-)
We can describe gravity's effects but we can't say how it does the trick.
General Relativity says gravity == acceleration. Therefore, the presence of matter and energy "slopes" space-time in such a way as to accelerate all other particles in the Universe.
When it comes down to it, it's all about the fourth dimension. Space only appears to contract because travel through the fourth dimension has slowed. Of course, since everything is relative both space contraction and time contraction are equally valid viewpoints of the same observation.;-)
Taking into account time dilation without time contraction is an incorrect calculation.
'Tis true. But our rocketman can *think* that he's traveled faster than light because he takes the measurements before his trip. If he then uses those measurements in his speed calculation, he'll find that he's traveled faster than light. Given that it's very difficult for our rocketman to make a measurement without again involving time, he could be forgiven the mistake. His only way of measuring the distance is by measuring via light. Since time is passing slower for him, a light year appears to have contracted into a much shorter distance.
An external observer might also note that our rocketman is quickly becoming flatter than a pancake thanks to Lorentz Contraction.;-)
Actually, at the speed of light, traveling towards the arth from Alpha Centauri, light from Sol would be traveling at 600,000km/sec in relationship to him.
You're off by a factor of 2. Light travels ~300,000 km/sec to all observers.
Light originating from his ship would be travling at normal speed to him, but faster or slower in perspective to anyone (or anything) he was passing.
Nope. Light originating from his ship would travel ~300,000 km/sec to him and anyone else who might be watching.
So, the speed of incidence would be Pa + Pb, which to either photon would be rather high.
That's Newtonian physics, which Einstein disproved. The speed of the photon will always be Pb. Have you read "Elegent Universe" yet? It's the best explanation I've ever seen. In short, we're all traveling at light speed through four dimensions. By traveling faster through space, we travel slower through time. This scales so perfectly, that we will always measure light as going ~300,000 km per one of our current seconds. We may actually be reaching 99.9999% of the speed of light, but it will seem to us that light is still traveling at ~300,000 km/sec. If we manage to obtain light speed, our time dilation will become infinite and we will forever be frozen in time. Thus photons never age, because they expend their entire velocity in only 3 dimensions.
Fine. Then I'll take back my gaming libraries. After all, what use is one of the most popular Java Gaming libraries in existence from a mere "armchair manager"? But you're the one who's breaking it to the Wurm Online project. And after that, maybe I'll take back my hundreds of other contributions to compression software, SQL Server drivers, popular Look and Feels, etc.
He still cannot accelerate to or past the speed of light.
You're missing the frame of reference. Yes, you can't actually *catch* light. Light speed will always be light speed. But from a frame of reference on a rocket ship experiencing time dilation, you can most certainly accelerate to a speed that would *appear* faster than light.
So thanks to time dilation, I can make it to Alpha Centauri in 6 months. But to everyone back home, it took me 4 years. Which one is correct? The answer is that both are. To the observer on board the ship, he's traveled 8 times the speed of light without ever passing a photon. To the observers on Earth, he's never gone faster than light speed. You see, it's all relative.
An interesting aspect of our universe is that every particle is already traveling light speed. (It's in Elegent Universe. Go ahead, look it up. I'll wait.) The trick is that our trajectory is in 4 dimensions. By traveling faster in three dimensions, we travel slower through the forth. i.e. Everyone on our slow planet is aging very quickly. We just don't know it because we have no other frame of reference. But if you speed up to 99.99% of c, you will age much more slowly than people on Earth. The reason is that you are now traveling slower in the forth dimension.
If this isn't making sense to you, then you need to reread Elegent Universe.:-)
Interesting tidbit: Einstein called his theory (in original German) "The Theory of Invarients", since the speed of light was constant in all frames of reference. It was an english speaking collegue of his that dubbed it "Theory of Relativity".
Allow me to clarify. Our rocketman takes a trip from Earth to Alpha Centauri. His rocket is so powerful, that he makes it there in 6 months his time. Rounding the distance to an even 4 lightyears, means that he's traveled 8 times the speed of light! And yet on his journey, he is never actually able to pass a photon. The blasted little buggers keep running ~300,000km/sec faster than he is! He then gets back to Earth in another 6 months and finds that everyone has aged ~10 years more than he has.
He soon learns that to everyone on Earth, time has passed much more quickly. So much more quickly, that they were able to observe the fact that he never exceeded light speed. "Poppycock!", he says. "I got there and back inside a year!" Which from his frame of reference is correct. But because everything is relative and all frames of reference are equally valid, the observations that he never traveled faster than the speed of light are also correct.
Remember, everything is relative. All frames of reference are equally valid, and there is no "universal speeed limit". There is however, a universal time dilation limit. Once you reach light speed (impossible with a rocket or particle accelerator), you'll be forever frozen in time (just like a photon).
You misunderstand. To the observer on a rocket, they can travel ten, one hundred, or even one million times the speed of light. He never actually *passes* light however. It would seem to him that light speeds up just to frustrate him.
What's really going on is that time is dilating. And since our rocketman measures speed as "distance traveled per time", he calculates his speed differently than an observer watching him on Earth would. To an Earth-bound observer, his rocket ship never exceeds light speed. All that appears to happen is that his engines appear to slow down their rate of burn. To the observer on the craft, he's still accelerating at the same rate he always was. So the rocketman can jet home in ten minutes (hey, you actually CAN get anywhere in 10 minutes!), but everyone at home will have aged by however many lightyears he traveled.
Because schools nail silly ideas into people heads, and Einsteins book "Relativity: An Explaination That Anyone Can Understand" wasn't so easy to understand?
General relativity states that nothing can *accelerate* to the speed of light.
Err... I thought that was Special Relativity. General Relativity deals with the way that gravity works. i.e. Gravity is acceleration. Therefore, matter and energy must curve space-time to make a "downward" slope.
That being said, you have the "halfway" problem of accelerating to light speed. As you accelerate, time dilation increases. As time dilation increases, your engines are less effective to an external observer. Therefore it becomes a lot like drawing a line halfway to the destination, then drawing another line halfway of the remainder, ad infinitum. You'll never reach the end. And because your mass increases, you could only use a rocket (converts your near infinite mass -> energy) to make the transition. An external force like a particle accelerator doesn't have enough energy (infinite) to push you to light speed.
It says nothing about things already going the speed of light.
Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
Experiments in Photon / Quantium Tunneling have indicated that photons can apear to tunnel through barriers faster then light.
That really has more to do with Quantum Mechanics than relativity. Overall, the photon is incapable of exceeding light speed. However, it can temporarily "steal" a bit of energy from nearby particles to tunnel out of existance and into existance elsewhere. The amount stolen is then payed back, resulting in a zero sum gain in velocity.
There are many things in this universe that appear to defy light speed. Unfortunately, not one of them is capable of transmitting useful information faster than light. Considering that this holds true at all levels of physics, one would almost conclude that the universe is out to "get" us.:-)
Building a ship to go faster than the *speed* of light is (relatively, ha ha) easy. Building a ship to *pass* light is difficult. No matter how fast you chase after that light (even if you cross the universe in seconds!), it will always remain 300,000 km/sec faster than you are! And if you do manage to reach light speed (good luck) you'll be just as frozen in time as photons are. In other words, you'll get to travel the universe, but you'll never know that you did it.
Of couse, the only way we know we're travelling "faster than the speed of light" is that we can measure the time between our point of origin and our point of destination. Time dilation makes sure that we're never able to pass light. If there was nothing else in the universe but your ship and light, you'd have no way of knowing that you were moving! How annoying is that?
They could be called to testify that in their professional opinion the code is free from defects. Conflict of interest might be an issue, however. Of course, since SCO can't actually produce any evidence, I don't think things will get that far.
As it is written: "There are no good excuses for binary modules. Some of them may be technically legal (by virtue of not being derived works) and allowed, but even when they are legal they are a major pain in the ass, and always horribly buggy."
And now we come full circle to my original post:
I think it's worth pointing out that Linux would also have drivers by now if they wouldn't keep up this religious crusade to get source only drivers.
How about a little less religion and a little more compsci + logistics management + good coding practices? Making a stupid piece of code your god/way of life tends to blind one to using the intelligence that God gave them.
Nothing, it was an example for a well done interface. Just so people won't say there isn't any.
Anyone who's used KDE and OEM Gnome can say with certainty that there are nice desktops for Linux. I'm glad that OEOne is also in the fray, but third party software is the real problem.:-)
Zero Install is a step in that direction. At the very least it's distribution agnostic. But for some reason there's a huge number of about 20 apps which provide ZI packages.
Indeed. I keep waiting for Zero Install to go somewhere. I think their biggest mistake is giving it the impression of being tied to Rox. Rox is great, but not everyone wants it. Also, I think they need to downplay the repository a bit more. It should be like Apple, comes from anywhere and installs with ease.
Kernel modules (just like Windows Device Drivers) can be made kernel independent. Then all it would take is an auto-extract to the modules folder. But Linus has stated that he doesn't want to allow vendors to distribute binary only drivers. So, the ones who are willing to put up with it, distribute a binary library to be linked into the kernel with a little bit of "glue" source. Thus they have effectively circumvented Linus's intentions.
All that source-only modules accomplish is to piss off users and vendors alike.
I think it's worth pointing out that Linux would also have drivers by now if they wouldn't keep up this religious crusade to get source only drivers. It's pretty annoying when you either have to download binaries that match your kernel version (good luck) or install all the kernel sources + dev tools + libraries, just so you can compile the drivers yourself. Vendors don't want to deal with this mess. It makes for massive support costs.
It isn't linux's fault that other venders want to offer thier proprietary software in a source distrobution rather then a prepackaged binary. That analogy while valid seems to goto more of the effect that "sofware vendor aren't ready for linux on the desktop" rather then linux isn't ready.
So you're saying that our mythical "Grandma" should know how to compile from source!? That is *completely* unreasonable. Not only will installs take forever, but there are a variety of different reasons that compiles might fail on similar environments. Not to mention that Grandma is going to freak when she sees all this garbage text going by. You know what she's going to do? "Give me back my Windows, NOW!"
You don't win market share by forcing stupid religious decisions on consumers.
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Earth accelerates down?
Earth accelerates nearby objects toward it. From your perspective on the surface, the Earth accelerates your plumb bob "down".
Acceleration is change in rate of change of position over time.
Yep. And the Earth's gravity *is* 9.8m/s2 of acceleration on all particles. The fact that other forces may be withholding the particles from falling (e.g. our plumb bob is hanging from the ceiling) does not mean that they are not accelerating. As I said, a water bottle rocket may be made to hang in the air contrary to gravity by tying a string to the end, but it is still accelerating.
In the middle of space, with an equal gravitaional force from all directions, in a ship accelerating at 1G, two plumb bobs hanging side by side will hang parallel.
You're using one of the biggest no-nos of math. You're mixing polar coordinates with cartesian coordinates. The plumb bobs will tend toward the center of the gravity well. The gravity well pulls from a spherical region around it. (Polar coordinates) A rocket ship applies equal force across a surface area, thus has cartesian coordinates. In order to decides if the two are equivalent, you have to apply math to cancel out the polar coordinates.
Why does everyone keep talking about planets?! I didn't mention planets. I'm talking about space-faring races. These space travelers with similar frames of reference could easily continue conflicts for millions of our years.
As for supply replenishment, it doesn't matter as long as you decelerate for only a short period of time. e.g. Two ships are traveling side by side at 99.99% c. As they pass near a solar system one suddenly disappears for a second or two, then reappears from behind with new weapons, ore, food, and men. In reality, the ship that disappeared has been gone for a year, but thanks to relativity it's able to rejoin the battle with no significant loss in time.
In my living room, the bobs wont be parallel, but on the ship they will be.
The Earth is curved. Your plumb bobs will attempt to seek the center of the gravitational distortion. Thus they will not be exactly parallel. Of course, things get a little dicey the closer you get to the ground. Because every particle pulls with the same gravitational "weight" as all other particles, your results will start to get screwy. Instead of having one gravitational vector, you're going to have to start calculating for the diagonal pull of other particles. And if you go underground, you'll be pulled up, down, left, and right simultaneously. Unless you go very, very deep, you will still perceive down as down, but you may find yourself getting a bit lighter as time goes by.
I want to use two plumb bobs and the results disprove your assertion. There is an obvious measurable difference in the behaviour of the pairs plumb bobs under acceleration versus a pair of plumb bobs in gravity. Why is my experiment not valid?
;-)
Get off of Earth. Earth has gravity, therefore accelerates DOWN. So moving inside a train causes your plumb bob to point in a direction that is a sum of the two vectors. i.e. diagonal. Once you are outside of the influence of gravity fields, a rocket accelerating at 1 G would work and feel just like standing on a planet. "Up" would be the nose, "Down" would be the engines.
Oh, since my plumb bobs are unpowered, they don't attempt to accelerate toward anything.
Want to bet? Hold your plumb bob up in the air by its string. It's pointing toward the ground, right? Now let go of it. If it didn't accelerate, it should stay still. (In fact, this is exactly what would happen in deep space.) Instead, your plumb bob accelerates at 9.8 m/s2. By the time it hits the floor, it will be going significantly faster than it was when you were holding it.
The reason why the plumb bob didn't go anywhere while you where holding it was because it has insufficient acceleration to overcome its captivity. e.g. It's like tying a string to the end of a water bottle rocket. The rocket will attempt to accelerate upwards, but it will be held taught at the length of the string.
To steal from an old song, "free your mind, and the rest will follow"
How is this bad? This is one of the cool things about relativistic travel. One of the bigger challenges we're facing right now is keeping people alive long enough to reach their destination. The good news is, if we travel at (or approach) c, this becomes less of a problem.
It's not cool to be forever stuck in time. Actually, it could kind of suck. Relativistic effects, OTOH, tend to suck for those who are planet-bound. They could send a spaceship out to explore the Universe, but it wouldn't be back until long after civilization has fallen and our Sun has gone cold. Under Newtonian physics, our intrepid space travelers would have been able to reach other planets super-fast to both them and people on Earth. Einstein kind of pokes a hole in that idea and said that relativistic travel over extreme distances means that you'll never again see your friends, family, and possibly even the human race.
I keep hearing this, but if you hang to plumb bobs near any mass, they don't hang parallel. Hang two plumb bobs in an accelerating ship and they do. Doesn't appear "==" to me.
Attach a plumb bob to the inside of the nose of a rocket. Now accelerate at 1 G of acceleration. What happens? The plumb bob "hangs" toward the back of the rocket. If we build decks parallel to the engines of the craft, our plumb bob will be perpendicular to the floor. Now hang a plumb bob in your home. Is it perpendicular to the floor?
You see, your plumb bob is attempting to accelerate toward the mass. Thus gravity == acceleration.
Now, I'd like to also point out that there is no real reason why we can't violate causality, causality is in fact highly overrated. People always tell the metaphorical story about someone going back in time to kill his father, but they never really think about it. Quantum uncertainty indicates that each time you go back the result will be a little bit different, so there is no such thing as an infinite loop (it must break 'eventually' because quantum uncertainty will cause you to burst into flame or get hit by a bus or whatever). So, go back, kill your father, don't exist, don't go back (because you don't exist), nobody kills your father, so you exist, so you go back......get hit by a bus, and there we have it, the time line is correct again.
At the risk of getting extremely theoretical here, I'd like to point out that an extra dimension of time would solve this issue. Einstein showed that we could perceive the fourth dimension by observing the rest of the Universe while traveling at a very different 3D speed in relation to it. To a space traveler, this would become a very intuitive thing.
But how would we see two dimensions of time? Well, Quantum mechanics states that instead of true cause and effect, we have all possible events at the same time. If there were any way to perceive that extra dimension, it would be as decisions/random events splitting the timeline. Each event in the universe would give the timeline a velocity into the fifth dimension. Thus timelines would exist were you did kill your grandfather and where you didn't. Causality is intact because you simply obtained a different fifth dimensional velocity by killing your grandfather.
The difficulty is in attempting to define vectors for such a dimension. If it did exist, how might one achieve a perpendicular trajectory in relation to the fourth dimension? If one did achieve a perpendicular trajectory, what would be the results? Is there any measurable thing in the universe that already "slides" perpendicular to the fourth dimension?
These are questions that it may take another Einstein to answer. I wonder if anyone's attempted any equations for this?
Maybe it's the other way around -- a hard speed-of-light barrier essentially makes interstellar war on any scale impractical.
Poppycock! If you had colonies/armies that always traveled at high percentages of c, then they'd all be within similar enough frames of reference that they'd be able to easily carry out wars. To everyone on a "slow" planet, a war would take anywhere from hundreds to millions of years, but to the factions fighting it's all happening within real-time.
When Kepler figured out the planetary orbits, he envisioned invisible brooms sweeping the planets towards the sun. When I read "gravity is just curved spacetime" I think of Kepler's brooms as they both seem to say about as much.
:-)
Think more like a bowling ball on a trampoline. The bowling ball will "warp" the trampoline, and objects placed on the trampoline will fall toward it.
As for planetary motion, I'm sure you've seen those funnels that you put coins in. The coin spins round and round. Friction eventually slows it down enough to fall toward the center. If your coin was in a vacuum and had sufficient velocity, it could keep going around the center forever. (e.g. The Earth keeps "missing" the Sun)
Just how does mass warp space? How does space know the mass is around?
We don't know the former yet. Space knows mass is around, because at a quantum level matter and energy are inbalances in the vacuum. "Empty" space is really a bunch of wild waves called "quantum foam" that all cancel each other out.
What particle is gravity's carrier?
Gravitons are only theoretical. At this point it looks like they don't exist. In other words, gravity waves are perpetrated in a vacuum instead of by a particle like the strong force's gluon.
If there is a gravity particle, how come planets don't speed up as they plow into them orbiting the sun?
If a planet heads toward the Sun (not a good thing) it *will* speed up. The trick is that a stable orbit implies having *just enough* speed to keep missing the object.
And how come it gets to escape black holes but no other particles can come out and play?
Because there's no particle. It's the nature of space-time.
We can describe gravity's effects but we can't say how it does the trick.
General Relativity says gravity == acceleration. Therefore, the presence of matter and energy "slopes" space-time in such a way as to accelerate all other particles in the Universe.
Response is here.
;-)
When it comes down to it, it's all about the fourth dimension. Space only appears to contract because travel through the fourth dimension has slowed. Of course, since everything is relative both space contraction and time contraction are equally valid viewpoints of the same observation.
Taking into account time dilation without time contraction is an incorrect calculation.
;-)
'Tis true. But our rocketman can *think* that he's traveled faster than light because he takes the measurements before his trip. If he then uses those measurements in his speed calculation, he'll find that he's traveled faster than light. Given that it's very difficult for our rocketman to make a measurement without again involving time, he could be forgiven the mistake. His only way of measuring the distance is by measuring via light. Since time is passing slower for him, a light year appears to have contracted into a much shorter distance.
An external observer might also note that our rocketman is quickly becoming flatter than a pancake thanks to Lorentz Contraction.
Actually, at the speed of light, traveling towards the arth from Alpha Centauri, light from Sol would be traveling at 600,000km/sec in relationship to him.
You're off by a factor of 2. Light travels ~300,000 km/sec to all observers.
Light originating from his ship would be travling at normal speed to him, but faster or slower in perspective to anyone (or anything) he was passing.
Nope. Light originating from his ship would travel ~300,000 km/sec to him and anyone else who might be watching.
So, the speed of incidence would be Pa + Pb, which to either photon would be rather high.
That's Newtonian physics, which Einstein disproved. The speed of the photon will always be Pb. Have you read "Elegent Universe" yet? It's the best explanation I've ever seen. In short, we're all traveling at light speed through four dimensions. By traveling faster through space, we travel slower through time. This scales so perfectly, that we will always measure light as going ~300,000 km per one of our current seconds. We may actually be reaching 99.9999% of the speed of light, but it will seem to us that light is still traveling at ~300,000 km/sec. If we manage to obtain light speed, our time dilation will become infinite and we will forever be frozen in time. Thus photons never age, because they expend their entire velocity in only 3 dimensions.
Fine. Then I'll take back my gaming libraries. After all, what use is one of the most popular Java Gaming libraries in existence from a mere "armchair manager"? But you're the one who's breaking it to the Wurm Online project. And after that, maybe I'll take back my hundreds of other contributions to compression software, SQL Server drivers, popular Look and Feels, etc.
He still cannot accelerate to or past the speed of light.
:-)
You're missing the frame of reference. Yes, you can't actually *catch* light. Light speed will always be light speed. But from a frame of reference on a rocket ship experiencing time dilation, you can most certainly accelerate to a speed that would *appear* faster than light.
So thanks to time dilation, I can make it to Alpha Centauri in 6 months. But to everyone back home, it took me 4 years. Which one is correct? The answer is that both are. To the observer on board the ship, he's traveled 8 times the speed of light without ever passing a photon. To the observers on Earth, he's never gone faster than light speed. You see, it's all relative.
An interesting aspect of our universe is that every particle is already traveling light speed. (It's in Elegent Universe. Go ahead, look it up. I'll wait.) The trick is that our trajectory is in 4 dimensions. By traveling faster in three dimensions, we travel slower through the forth. i.e. Everyone on our slow planet is aging very quickly. We just don't know it because we have no other frame of reference. But if you speed up to 99.99% of c, you will age much more slowly than people on Earth. The reason is that you are now traveling slower in the forth dimension.
If this isn't making sense to you, then you need to reread Elegent Universe.
Bonus link on the Speed of Light.
Interesting tidbit: Einstein called his theory (in original German) "The Theory of Invarients", since the speed of light was constant in all frames of reference. It was an english speaking collegue of his that dubbed it "Theory of Relativity".
Allow me to clarify. Our rocketman takes a trip from Earth to Alpha Centauri. His rocket is so powerful, that he makes it there in 6 months his time. Rounding the distance to an even 4 lightyears, means that he's traveled 8 times the speed of light! And yet on his journey, he is never actually able to pass a photon. The blasted little buggers keep running ~300,000km/sec faster than he is! He then gets back to Earth in another 6 months and finds that everyone has aged ~10 years more than he has.
He soon learns that to everyone on Earth, time has passed much more quickly. So much more quickly, that they were able to observe the fact that he never exceeded light speed. "Poppycock!", he says. "I got there and back inside a year!" Which from his frame of reference is correct. But because everything is relative and all frames of reference are equally valid, the observations that he never traveled faster than the speed of light are also correct.
Here's a link for you on this oddity of relativity:
http://www.fourmilab.ch/cship/cship.html
Remember, everything is relative. All frames of reference are equally valid, and there is no "universal speeed limit". There is however, a universal time dilation limit. Once you reach light speed (impossible with a rocket or particle accelerator), you'll be forever frozen in time (just like a photon).
You misunderstand. To the observer on a rocket, they can travel ten, one hundred, or even one million times the speed of light. He never actually *passes* light however. It would seem to him that light speeds up just to frustrate him.
What's really going on is that time is dilating. And since our rocketman measures speed as "distance traveled per time", he calculates his speed differently than an observer watching him on Earth would. To an Earth-bound observer, his rocket ship never exceeds light speed. All that appears to happen is that his engines appear to slow down their rate of burn. To the observer on the craft, he's still accelerating at the same rate he always was. So the rocketman can jet home in ten minutes (hey, you actually CAN get anywhere in 10 minutes!), but everyone at home will have aged by however many lightyears he traveled.
Does that make sense?
Why do you humans always misquote Einstein.
:-)
Because schools nail silly ideas into people heads, and Einsteins book "Relativity: An Explaination That Anyone Can Understand" wasn't so easy to understand?
General relativity states that nothing can *accelerate* to the speed of light.
Err... I thought that was Special Relativity. General Relativity deals with the way that gravity works. i.e. Gravity is acceleration. Therefore, matter and energy must curve space-time to make a "downward" slope.
That being said, you have the "halfway" problem of accelerating to light speed. As you accelerate, time dilation increases. As time dilation increases, your engines are less effective to an external observer. Therefore it becomes a lot like drawing a line halfway to the destination, then drawing another line halfway of the remainder, ad infinitum. You'll never reach the end. And because your mass increases, you could only use a rocket (converts your near infinite mass -> energy) to make the transition. An external force like a particle accelerator doesn't have enough energy (infinite) to push you to light speed.
It says nothing about things already going the speed of light.
Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
Experiments in Photon / Quantium Tunneling have indicated that photons can apear to tunnel through barriers faster then light.
That really has more to do with Quantum Mechanics than relativity. Overall, the photon is incapable of exceeding light speed. However, it can temporarily "steal" a bit of energy from nearby particles to tunnel out of existance and into existance elsewhere. The amount stolen is then payed back, resulting in a zero sum gain in velocity.
There are many things in this universe that appear to defy light speed. Unfortunately, not one of them is capable of transmitting useful information faster than light. Considering that this holds true at all levels of physics, one would almost conclude that the universe is out to "get" us.
Building a ship to go faster than the *speed* of light is (relatively, ha ha) easy. Building a ship to *pass* light is difficult. No matter how fast you chase after that light (even if you cross the universe in seconds!), it will always remain 300,000 km/sec faster than you are! And if you do manage to reach light speed (good luck) you'll be just as frozen in time as photons are. In other words, you'll get to travel the universe, but you'll never know that you did it.
Of couse, the only way we know we're travelling "faster than the speed of light" is that we can measure the time between our point of origin and our point of destination. Time dilation makes sure that we're never able to pass light. If there was nothing else in the universe but your ship and light, you'd have no way of knowing that you were moving! How annoying is that?
They could be called to testify that in their professional opinion the code is free from defects. Conflict of interest might be an issue, however. Of course, since SCO can't actually produce any evidence, I don't think things will get that far.
As it is written: "There are no good excuses for binary modules. Some of them may be technically legal (by virtue of not being derived works) and allowed, but even when they are legal they are a major pain in the ass, and always horribly buggy."
And now we come full circle to my original post:
I think it's worth pointing out that Linux would also have drivers by now if they wouldn't keep up this religious crusade to get source only drivers.
How about a little less religion and a little more compsci + logistics management + good coding practices? Making a stupid piece of code your god/way of life tends to blind one to using the intelligence that God gave them.
Nothing, it was an example for a well done interface. Just so people won't say there isn't any.
:-)
Anyone who's used KDE and OEM Gnome can say with certainty that there are nice desktops for Linux. I'm glad that OEOne is also in the fray, but third party software is the real problem.
Zero Install is a step in that direction. At the very least it's distribution agnostic. But for some reason there's a huge number of about 20 apps which provide ZI packages.
Indeed. I keep waiting for Zero Install to go somewhere. I think their biggest mistake is giving it the impression of being tied to Rox. Rox is great, but not everyone wants it. Also, I think they need to downplay the repository a bit more. It should be like Apple, comes from anywhere and installs with ease.
Allow me to pose the question:
Why?
Kernel modules (just like Windows Device Drivers) can be made kernel independent. Then all it would take is an auto-extract to the modules folder. But Linus has stated that he doesn't want to allow vendors to distribute binary only drivers. So, the ones who are willing to put up with it, distribute a binary library to be linked into the kernel with a little bit of "glue" source. Thus they have effectively circumvented Linus's intentions.
All that source-only modules accomplish is to piss off users and vendors alike.
I think it's worth pointing out that Linux would also have drivers by now if they wouldn't keep up this religious crusade to get source only drivers. It's pretty annoying when you either have to download binaries that match your kernel version (good luck) or install all the kernel sources + dev tools + libraries, just so you can compile the drivers yourself. Vendors don't want to deal with this mess. It makes for massive support costs.
It isn't linux's fault that other venders want to offer thier proprietary software in a source distrobution rather then a prepackaged binary. That analogy while valid seems to goto more of the effect that "sofware vendor aren't ready for linux on the desktop" rather then linux isn't ready.
So you're saying that our mythical "Grandma" should know how to compile from source!? That is *completely* unreasonable. Not only will installs take forever, but there are a variety of different reasons that compiles might fail on similar environments. Not to mention that Grandma is going to freak when she sees all this garbage text going by. You know what she's going to do? "Give me back my Windows, NOW!"
You don't win market share by forcing stupid religious decisions on consumers.