What do you think relative to The theory of relativity?
123716
as many others have said, the first chicken was the offspring of a genetic "proto-chicken." Certain genetic mutations changed the child from the parent and made the offspring different from the parent and officially a chicken. By definition, the offspring of a chicken has a chicken parent.
396662
Nobody really knows.  Einstein's special theory of relativity posits gravity as a warp of space-time caused by the object's mass, but that only pushes the question one layer further down.  All we know for sure is that gravity exists, is pervasive, and can be important.
364105
hyperbolic plane, you can check what the different models for hyperbolic geometry are.\n\nanotherone, would be Riemannian geometry, which is the basis for relativity theory.\n`
601335
That question goes in line with my latest thought on einstein theory of relativity.  If something approaches the speed of light (or at the speed of light) time slows for it but not the observer, so how do we measure it if the light itself is time compressed?
514460
Simultaneity in Special Relativity is based on 2 assumptions:\n\n- the laws of physics apply equally to all inertial reference frames\n- the speed of light in empty space is constant and independent of the relative motion of its source\n\nThis implies that there is no absolute simultaneity, meaning that two events that happens at the same time in one inertial frame may not happen at the same time in another inertial frame.\n\nSo Einstein is NOT defining Simultaneity based on the invariance of the speed of light in all inertial frames, but instead the failure of absolute Simultaneity is a consequence of the invariance of the speed of light in all inertial frames.\n\nSo why does the invariance of the speed of light in all inertial frames imply the lack of Simultaneity? The argument for this is exactly the same as why there can be no absolute reference frame if we assume that the speed of light is constant in all reference frames.\n\nThe only way for the speed of light to be constant in all reference frames is for distance and time to be relative and be a function of speed of the reference frame, i.e. speed = distance/time implies that distance must contract and time must dilate if the reference frame is moving with a certain speed.\n\nSo if distance and time is different in one reference frame than another, then there is no way that two observers, each in separate reference frames, can agreed on when some event has happened. Thus simultaneity is violated.
314479
Einstein’s Special Theory of Relativity started with two postulates: 1) that the laws of physics are observed to be the same in any non-accelerated reference frame and 2) that the speed of light (c) is observed to be the same for all observers.\n\nThe first assumption isn’t too worrisome, but the second seems trickier.  It’s certaonly not intuitively obvious, but it makes sense from both a theoretical and an observational perspective.  Observational because the Michelson-Morley experiment (and others) detected no change in the velocity of light when measured from a moving frame of reference; theoretical because Maxwell’s Equations yield a specific value for the velocity of light.\n\nWhen Einstein considered Maxwell’s Equations, he realized that they don’t allow for a “standing wave” solution, which is what a light wave would look like if you were travelling at the speed of light.  So he already sensed there would be a problem with travelling at very high speeds.  Indeed, when you re-work the addition of velocities, it comes out to be not simple addition, but a fraction that never gets larger than c.  \n\nThus, in the photon-photon collision you describe, each photon would “see” the other one travelling toward it with a velocity c.  (Although measuring velocities from a photon’s perspective is a little non-intuitive; you have to take the limit of the aforementioned addition formula, which causes some trepidation.)\n\nOh, and the ten-dimensional idea is just one among many…  No way yet to prove (or disprove) that one.\n\n\nRyan Wyatt\nRose Center for Earth & Space\nNew York, New York
211587
That version of Einsteins theory of general relativity is only for particles with 0 momentum.  for ones that do wave momentum but no mas it is\nE= pc (p=momentum, c= speed of light)\n\nbut yes, it is only applicable for at the speed of light hence it only has c, the speed of light, and not v, another speed.
272050
All a theory does is attempt to explain evidence.  If it does a good job explaining evidence, and if it stands up to being able to predict the results of future experiments, then it has a lot going for it.  Relativity theory does a good job of explaining a lot of experimental evidence that had 19th century physicists scratching their heads.  Special relativity helped explain the results of the Michelson-Morley experiment, which showed that the speed of light is essentially the only thing on which any two inertial observers can agree; general relativity was able to predict the curving of light around the sun and explain the precession of the perihelion of Mercury's orbit, and a myriad of other phenomena since.  Unfortunately, general relativity and quantum mechanics don't play very well together.  Since quantum mechanics ALSO does a good job of explaining a lot of things, we start to look for ways of describing the universe which include both the relativistic and quantum viewpoints.  (One can loosely think of relativity describing "big" objects and distances, and quantum theory describing "small" objects and distances.)  There have been big inroads made in this effort (quantum field theory), but no firm answers yet.  What is needed to validate a theory is to take the theory's predictions and compare them to experimental results.  I'm not a physicist, and I don't know where the current state of research is as regards testing such predictions.  Just bear in mind that, even if some flavor of QFT becomes the "new" relativity theory so to speak, it doesn't completely invalidate relativity theory.  After all, we still use the techniques of Newtonian physics for many things (the first quarter of any freshman level physics class in college is largely thanks to Newton!), because even though Newtonian techniques don't provide the correct answer (as say, compared to the techniques of general relativity), the error produced is often so small that it would be darn near impossible to tell the difference.
143939
Wow, great question(s)!  You're brooding over something called the 'twin's paradox', read more about it in the link below.  Basically, what you're fretting over are a couple of the (wierd) implications of special (and general) relativity.  You (and what some others have said) are right, all velocity is relative, which comes from the simple fact that there is no special place that we can call 'still' which we could measure our velocity against.  The single exception to this lies in the speed of light, which is constant for everyone everywhere, no matter what their speed is relative to anything else.  (Note: light isn't special, the only reason it's able to travel at the upper speed limit is because it's particles, photons, have no mass.  Nothing with mass can ever travel AT the speed of light, only near if it is pumped up with huge amounts of energy.)  Think about the wierd implications of this; even if you were able to travel at 99.999999% the speed of light, and your friend would also be able to travel the same speed in the opposite direction, if you shined a light back toward your friend and could measure the photon's speed as they travelled between you the photons would STILL be travelling at the speed of light.  Ok, what does that mean?  The speed of light is just a speed, like any other, but is a constant that can not be exceeded.  Well, like any other speed, c (the usual symbol for the speed of light) is definded as the ratio of the distance travelled (call it 'x') by the time it took to travel it (call it 't'), or c=x/t.  But if 'c' can't change (because it's a constant) what is changing?  There's only two other things in the equation, x (the distance, a measure of space) and t.  Time and space enter into Einstien's equations here, the only way to keep c constant is for x and t to somehow collaborate to change together to make it so.  This is why time (and space) are so 'relavent' to velocity.  And as a matter of fact, time is 'relavent' to gravity as well, as Einstein pointed out so much better than I can.  For Einstein, the breakthrough came when he realized that there is no measurable way to distinguish between gravity and acceleration (a.k.a. the rate of change of velocity with respect to TIME), or more importantly, between the lack of gravity (say a person floating in space) and a particle (or person) in a falling box, they're indistinguishable.  From these two simple ideas (the constancy of c, and the equivalence of gravity and acceleration) Einstein formulated the theory of general relativity, one of the crowning achievements of human thought.  You ask good questions, keep wondering!
629597
Einstein's law of gravitation. It certainly looks nicer than Newton's :P
179727
Ask around if any of your friends have a GPS system.  There is your example of a daily-life example of the theory of relativity.  The Global Positioning System would not be able to give you very accurate locations if it did not take the corrections to time and distance from both special, and general reletivity into account.  I am pretty sure that it is the first piece of public consumer-grade equiptment that relies on our understanding of General Relativity.
568320
there is a important factor that appears in the theory of relativity:\nit's called "gamma" (we use the greek letter usually).\nFor a body moving with the velocity v, we have \ngamma=1/squareroot(1-v^2/c^2) , where c is the velocity of light.\nas you can check, as v increases (but always being lower than c), gamma becomes bigger and bigger, tending towards infinity as v tends to c. You can also check than when v=0, gamma=1.\n\nIn non relativistic theory, the mass of a rod for example is called "m" and its length "L". In the point of view of the rod, m and L are constant. For an outside observer also...\nBut what the theory of relativity shows is that for the outside observer, the mass and length of a rod moving with a velocity v is no more m and L, but gamma*m and L/gamma.\nThus, if the velocity is much smaller than c (everyday experience), gamma~1 and nobody can see the difference, if the velocity increased a lot, gamma->iinfinity, and thus the mass also tends towards infinity and the length tends towards 0...  for the outside observer!    If you are the rod, your velocity compared to yourself is 0, so your "own gamma" is 1 and your length and mass, in YOUR point of view, is constant.\n\nthe theory of relativity shows that "basic" things such as the length, the mass (and even the time between two events) of an object depends on the observer. \n\nI hope I've been a bit helpful. Go on with your reading, don't be afraid if you do not understand everything at the first and even the tenth reading, that comes with experience...
112252
yeah, you get a bit off on a deep tangent towards the end there... but I don't think Einstein asserted anything more than the idea that time, space, and matter are related and not independant.  two systems of matter travelling in wildly different velocities relative to one another also have different processions of time and different masses, from the perspective of the other.  It only applies to things moving close to the speed of light- I think it's the Schroedinger Equation that covers the inter-relation.  But there's no real analogy to it in the observable world, unless you work at a particle accelerator, so I leave it to the doctorates of physics to debate.
47816
i like to contemplate the coming together of Heisenberg"s uncertainty principle, string theory, and the theory of relativity (special edition).\n\ni feel it was best described and visualized in the TV series farscape.\nthe explanation was wonderful.\nthe visuals helpful.\nputting aside fiction, i think the universe maker breaker force is essential to defining the glue of everything.\n\n\n"In quantum physics, the Heisenberg uncertainty principle states that one cannot assign, with full precision, values for certain pairs of observable variables, including the position and momentum, of a single particle at the same time even in theory. It furthermore precisely quantifies the imprecision by providing a lower bound (greater than zero) for the product of the standard deviations of the measurements. The uncertainty principle is one of the cornerstones of quantum mechanics and was discovered by Werner Heisenberg in 1927.\n\nIt is sometimes called the Heisenberg indeterminacy principle (a name preferred by Niels Bohr)."\n\n"string theory \n \ndescription of elementary particles based on one-dimensional curves, or "strings," instead of point particles. Superstring theory, which is string theory that contains a kind of symmetry known as supersymmetry, shows promise as a way of unifying the four known fundamental forces of nature. The strings are embedded in a space-time having as many as 10 dimensions–the three ordinary dimensions plus time and seven compactified dimensions. The energy-scale at which the stringlike properties would become evident is so high that it is currently unclear how any of the forms of the theory could be tested.\n\nSee P. C. W. Davies and J. Brown, ed., Superstrings (1988)."\n\n"Special Relativity\nNewton's laws of motion give us a complete description of the behavior moving objects at low speeds. The laws are different at speeds reached by the particles at SLAC. \n\nEinstein's Special Theory of Relativity describes the motion of particles moving at close to the speed of light. In fact, it gives the correct laws of motion for any particle. This doesn't mean Newton was wrong, his equations are contained within the relativistic equations. Newton's "laws" provide a very good approximate form, valid when v is much less than c. For particles moving at slow speeds (very much less than the speed of light), the differences between Einstein's laws of motion and those derived by Newton are tiny. That's why relativity doesn't play a large role in everyday life. Einstein's theory supercedes Newton's, but Newton's theory provides a very good approximation for objects moving at everyday speeds. \n\nEinstein's theory is now very well established as the correct description of motion of relativistic objects, that is those traveling at a significant fraction of the speed of light.\n\nBecause most of us have little experience with objects moving at speeds near the speed of light, Einstein's predictions may seem strange. However, many years of high energy physics experiments have thoroughly tested Einstein's theory and shown that it fits all results to date."
17012
einstein's theory of relativity.  in the frame of reference of the car, you are stationary, the fly is stationary, and everything else in the car or moving with the car is stationary. this is why if you are in a car and drop a book onto the seat, it goes straight down, not toward the back. it is going at the same speed as the car and therefore is still relative to the car. there is no force acting on it to make it behave otherwise.  that's why you don't feel anything in a car unless you're accelerating or decelerating. so you feel like you're pushed forward when the car is coming to a sudden stop. because then there's a force stopping the car, and therefore you, so you feel it. in this case, the fly would also go flying(no pun intended) to the front of the car.\n\nif this is still unclear, think of the earth. the earth is rotating with a speed of over 1000 m/s, but you don't feel it. that's because you're moving at that same speed, you're stationary relative to the earth so you feel stationary because your frame of reference is the earth.
4021
well yeah... \nwell we dont have any definitive start or end point, so it's only relative to itself meaning that you can only measure a change in time, not how much of it you actually have. \nyour actual question is a little ambiguous, if this isnt what you meant, you can add some to the question,  are you looking for an explanation of how high velocities distort time or something, because I can explain that if you would like, just add it onto the question or make a new one or something.
271887
Einstein postulated that the speed of light would remain the same regardless of the inertial frame in which it is measured.  This contradicts classical physics, since if an object is moving at a velocity v, as measured in an inertial frame, and that inertial frame is moving with a velocity v2 with respect to a second inertial frame, then you should take the vector sum of the two velocities to determine the velocity of that object with respect to the second inertial frame.\n\nEinstein postulated that within an inertial frame the laws of classical physics held.  So, to make things work out Einstein calculated that time and space are distorted with velocity.  It is as though you and your brother are of different heights, but you both want to be the same height, so you take a rubber ruler and stretch it so you get the same measurement for the two of you.\n\nIn this way you always measure the speed of light as the same value, no matter how fast the source of the light is moving with respect to you.  You adjust the rubber ruler so that what you want to believe remains true.