Was the bending of a light ray to gravity per Einsteinn's formulation really a curved light ray?
436707
Yes.\n\nBending of light is most easily observed during gravitational lensing, where a dense, distant object bends light sufficiently that you can image an object directly behind it.  In these scenarios, the phase changes exhibited by the light (a distance dependent-phenomenon) are entirely consistent with the smooth, curved path expected from theory, not a sudden sharp change.\n\n[Edit]\n\nAnd in response to your edit - yes.  Light is bent by gravity, even infinitesimally - and since there is mass, and hence gravity, in the universe, light rays are bent - just not noticeably on a local scale!
456899
because its the shortest path. light does not bend with gravity, spacetime bends with gravity, changing the shortest path.
13615
Great question.\n\nYou're looking for something physical, but nothing physically warps.  As you said, there's no aether or medium.\n\nThe "warping" is kind of a metaphor for what happens in a mathematical model.  They talk about that and the rubber mat to help people visualize something that's really difficult to grasp, or even believe.\n\nWe've all learned from Newton that an object in motion will continue moving in the same direction and speed unless acted upon by another force.  Well, you can describe gravity as an outside force, as Newton did, and that's pretty easy to understand.  A comet comes flying by the Earth, but the Earth's gravity continually pulls on the comet, and changes its course.\n\nGeneral Relativity takes a different approach to describing the effect of gravity.  It says that gravity isn't a force.  In its version of reality, the comet keeps moving in a perfectly straight line.  Except that a mass can bend the lines.  Yeah.  No aether or medium.  But straight lines are bending.  It's a model to describe how gravity has the effect it has.\n\nWhy do scientists buy into this?  Well, experiment has shown that gravity bends light, and our current understanding of light says that light has no mass.  So the old model of gravity, which acts only on mass, can't explain this.
425047
There was a problem with his theory. See the rest of the article at:\n\nNewton's aether model\nFrom Wikipedia, the free encyclopedia\nhttp://en.wikipedia.org/wiki/Newton's_aether_model\n\n"In his book Optiks Isaac Newton described a model that attempted to unify descriptions of light, matter and gravity by describing that both the action of gravity on light and the action of matter on light as effects of variations in lightspeed relate to the density of an underlying aetherial medium. This is referred to as Newton's aether model.\n\nNewton described light as starting to bend before it reaches the boundary of an air/glass surface, and related this deflection towards the region of greatest density to the tendency of paths to be deflected towards a gravity-source (again, to a region of greater mass-density). According to the model, particles and waves would be deflected in the same way, matter could be said to be "refracted" by the lightspeed gradient associated with gravity. Newton's postulated light-corpuscles - and the associated "wavelike" effects that he suggested were responsible for steering them - would be deflected in the same way. In modern language, we can say that Newton's aether model was an early attempt at a "geometrical" theory of gravity, or a curved-space model."\n\n"Critically, Newton had mistakenly inverted the relationship between lightspeed and refractive ability: he thought that light had an affinity for regions of higher rather than lower lightspeed. This meant that instead of saying that the aether was the gravitational field and/or the mass density (as with general relativity, Einstein 1920), Newton had to say that his medium was progressively displaced by the gravitational field and by matter, which was a less satisfying concept."
673110
Albert Einstein was the one who popularized the idea of curved space in his theory of general relativity (if you can call that 'popular').  As part of his theory Einstein assumed that light worked the same in space as it does on Earth, namely that it ALWAYS moves in straight lines.  This was an assumption on his part, but as part of trying to prove his theory (either right or wrong) astronomers photographed stars during a solar eclipse, tracking their motion to see if they were where they were supposed to be as their light grazed past the sun (the most massive object we have nearby).  Sure enough, the star's light wasn't exactly where it was supposed to be.  Think of it this way:  if light ALWAYS moves in a straight line (which it must for the general theory of relativity to work, which it does very well) and we see it curve, then the straight line must be curved.  It's space (along the light beam's path of travel) that comes out as the only element that can curve.  Just one more of the funny implication of living in a universe where everything tugs on everything else.\n\nWhat does it curve into?  Your guess is as good as anybody else's.
1005885
Suppose you travel over the earth surface with an aeroplane. Traveling you never meet a boundery, because the earth has been curved.\nIn the same way our universe has been curved as well (only one dimension higher) and a lightbeam never meets a boundery (except objects as as star or a space rock). If  the intensity of the beam is strong enough, it 'circles' the universe.
810449
Technically, no since a photon is a massless quanta of light or electromagnetic radiation.  However, the whole wave-particle duality must come into play.  Energy from the Sun can impart a force upon objects--hence the whole solar sail project.\nAnother reason a photon cannot have any mass is because only a massless object can move at the speed of light.  Now, if you're wondering how can light rays be "bent" by gravity if gravity only affects mass, the light rays simply travel straight lines, unaffected by gravity.  However, since gravity warps or curves space, sometimes those straight lines get bent.
1159614
The property of light is that it takes the shortest route possible between 2 pts. IT IS A WRONG IDEA THAT THIS PATH IS A STR LINE. A str line is the shortest dist in Eucidean Goem, the geom of the Universe is NOT EUCLIDEAN IN NATURE. As for your other ideas, I pt out that a photon never stops travelling unless it gives up its energy. DO NOT USE NEWTON'S LAWS ON THE PROPAGATION OF LIGHT. THE PROPAGATION OF LIGHT IS EXPLAINED BY 2 THEORIES-\nMAXWELLS THEORY OF ELECTROMAGNETISM, speaking of the WAVE ASPECTS\nEISTEIN'S GENERAL THEORY OF RELATIVITY, speaking of the particle nature. GO through these when you r of the proper age to do so, let me warn you that studying the true nature of light requires a huge pre-knowledge of physics and it is very difficult and controversial.
374885
The answer is no. Isaac Newton had assumed that light was made up of numerous small particles, in order to explain features such as its ability to travel in straight lines and reflect off surfaces. This theory was known to have its problems; although it explained reflection well, its explanation of refraction and diffraction was less pleasing. In order to explain refraction, in fact, Newton's Opticks (1704) postulated an "Aethereal Medium" transmitting vibrations faster than light, by which light (when overtaken) is put into "Fits of easy Reflexion and easy Transmission" (causing refraction and diffraction). Newton believed that these vibrations were related to things like heat radiation, saying:\n\nIs not the Heat of the warm Room convey'd through the Vacuum by the Vibrations of a much subtiler Medium than Air, which after the Air was drawn out remained in the Vacuum? And is not this Medium the same with that Medium by which Light is refracted and reflected, and by whose Vibrations Light communicates Heat to Bodies, and is put into Fits of easy Reflexion and easy Transmission? \nThe modern understanding, of course, is that heat radiation is light, but Newton considered them two different phenomena (believing heat vibrations to be excited "when a Ray of Light falls upon the Surface of any pellucid Body"). He wrote that "I do not know what this Aether is", but that if it consists of particles then they must be "exceedingly smaller than those of Air, or even than those of Light: The exceeding smallness of its Particles may contribute to the greatness of the force by which those Particles may recede from one another, and thereby make that Medium exceedingly more rare and elastick than Air, and by consequence exceedingly less able to resist the motions of Projectiles, and exceedingly more able to press upon gross Bodies, by endeavoring to expand itself."
234235
Light has no rest mass, since it can't be stopped without absorbing it, but it does have a mass equivalence due to its energy.  The energy of a photon of a particular wavelength of light is given by E=(h-bar)(nu) and the mass equivalence of energy is E=MC^2, so (h-bar)(nu)=MC^2, solve for M, and you get M=(h-bar)(nu)/C^2 as the mass equivalence for an individual photon.  It's a really, really small number, even for high energy wavelengths of light, plus light moves very fast past an object which could assert a gravitational pull on in, so light only bends by an observable amount in really high gravitational fields.
229251
Your dad was right: space-time curvature is not something you can really understand outside from the mathematics framework of general relativity.\nHowever, the concept of the space bending can be intuitively pictured by a simple thought experiment: imagine we lived in a 2-dimensional world, that is, on a flat surface. This means we live completely within the surface, never escaping from it, maybe not even knowing that there are other dimensions. Then suppose this surface is bent due to some effect (gravity, in our case). If the bending is strong enough (if there is enough mass in the universe), the surface may be so curved to close on itself, for example forming a sphere.\nIn this imaginary scenario, you may build a spaceship and travel in a straight line from your viewpoint. But remember, you are traveling within the sphere surface. Seen from a 3D observer, your straight line is a circle. Therefore, in the end you will get at the starting point of the circle.
474280
General relativity is the geometrical theory of gravitation published by Albert Einstein in 1915. It unifies special relativity and Isaac Newton's law of universal gravitation with the insight that gravitation is not viewed as being due to a force (in the traditional sense) but rather a manifestation of curved space and time, this curvature being produced by the mass-energy content of the spacetime.\n\nmore info for you :)
828289
It is exactly that question that inspired Einstein to formulate his theory that nothing can ever travel faster than light. I am not saying the Einstein had a goal to make a theory saying nothing can travel faster than light. I am saying that the question made him think about how to explain what would happen in such a case and then the math lead him to a theory of motion in general which says nothing can travel faster than light.
977539
On the contrary, a light beam would merely percieve that it travelled instantly inbetween origin and destination. Space would be warped to Zero distance in the direction of travel, not Zero space. I know it seems like a sleight-of-hand trick with the mathematics, but the distinction is important.
561186
First of all, it is fundementally impossible to go at the speed of light. Therefore, the question as stated is invalid.\n\nHowever, it may or may not surprise you that, indeed, it is THAT VERY QUESTION that Albert Einstein surmised in 1896.  Here is his quote:\n"If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest.  However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations.  From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest.  For how, otherwise, should the first observer know, i.e., be able to determine, that he is in a state of fast uniform motion?  One sees that in this paradox the germ of the special relativity theory is already contained.  Today everyone knows, of course, that all attempts to clarify this paradox satisfactorily were condemned to failure as long as the axiom of the absolute character of time, viz., of a simultaneous, unrecognizedly was anchored in the unconscious.  Clearly to recognize this axiom and its arbitrary character really implies already the solution to the problem."\n\nTherefore, In 1905 he realised how it could be that light always goes at the same speed no matter how fast you go.  Events that are simultaneous in one reference frame will happen at different times in another that has a velocity relative to the first.  Space and time cannot be taken as absolute.  On this basis Einstein constructed the theory of special relativity, which has since been well confirmed by experiment.\n\nNow, I can't explain any more than that.  So there :P
6001
yes!!\n\nBlack holes are predictions of Albert Einstein's theory of general relativity. In particular, they occur in the Schwarzschild metric, one of the earliest and simplest solutions to Einstein's equations, found by Karl Schwarzschild in 1915. This solution describes the curvature of spacetime in the vicinity of a static and spherically symmetric object, where the metric is\n\n    ds^2 = - c^2 &#92;left( 1 - {2Gm &#92;over c^2 r} &#92;right) dt^2 + &#92;left( 1 - {2Gm &#92;over c^2 r} &#92;right)^{-1} dr^2 + r^2 d&#92;Omega^2,\n\nwhere d&#92;Omega^2 = d&#92;theta^2 + &#92;sin^2&#92;theta&#92;; d&#92;phi^2 is a standard element of solid angle.\n\nAccording to Schwarzschild's solution, a gravitating object will collapse into a black hole if its radius is smaller than a characteristic distance, known as the Schwarzschild radius. Below this radius, spacetime is so strongly curved that any light ray emitted in this region, regardless of the direction in which it is emitted, will travel towards the center of the system. Because relativity forbids anything from travelling faster than light, anything below the Schwarzschild radius – including the constituent particles of the gravitating object – will collapse into the center. A gravitational singularity, a region of theoretically infinite density, forms at this point. Because not even light can escape from within the Schwarzschild radius, a classical black hole would truly appear black.\n\nThe Schwarzschild radius is given by\n\n    r_s = {2&#92;,Gm &#92;over c^2}\n\nwhere G is the gravitational constant, m is the mass of the object, and c is the speed of light. For an object with the mass of the Earth, the Schwarzschild radius is a mere 9 millimeters — about the size of a marble.\n\nThe mean density inside the Schwarzschild radius decreases as the mass of the black hole increases, so while an earth-mass black hole would have a density of 2 × 1030 kg/m3, a supermassive black hole of 109 solar masses has a density of around 20 kg/m3, less than water! The mean density is given by\n\n    &#92;rho=&#92;frac{3&#92;,c^6}{32&#92;pi m^2G^3}\n\nSince the Earth has a mean radius of 6371 km, its volume would have to be reduced 4 × 1026 times to collapse into a black hole. For an object with the mass of the Sun, the Schwarzschild radius is approximately 3 km, much smaller than the Sun's current radius of about 700,000 km. It is also significantly smaller than the radius to which the Sun will ultimately shrink after exhausting its nuclear fuel, which is several thousand kilometers. More massive stars can collapse into black holes at the end of their lifetimes.\n\nMore general black holes are also predicted by other solutions to Einstein's equations, such as the Kerr metric for a rotating black hole, which possesses a ring singularity. Then we have the Reissner-Nordström metric for charged black holes. Last the Kerr-Newman metric is for the case of a charged and rotating black hole.\n\nThere is also the Black Hole Entropy formula:\n\nS = &#92;frac{Akc^3}{4&#92;hbar G}\n\nWhere A is the area of the event horizon of the black hole, &#92;hbar is Dirac's constant (the "reduced Planck constant"), k is the Boltzmann constant, G is the gravitational constant, c is the speed of light and S is the entropy.
126640
In general relativity, mass affects space and time, causing what we call gravity, and time dilation. The equations predicted that clocks in a gravity field would run more slowly, although the effect is very slight for most masses that we are familiar with, like the Earth. It has been measured and agrees well with predictions.\n\nSimilarly, the equations predicted that light would be bent around a mass, like the sun, and this has also been proved to be correct. In fact, strong gravity sources can create illusions, sometimes splitting the image of a light source behind a high-gravity object so it appears to us to be two separate images.\n\nA new discovery is that the rotation of a gravity source, like the sun or a galaxy, causes "frame dragging", that is, distorts spacetime like water around a spinning ball, also predicted by Einstein's theory.\n\nThere are a lot of good science sites on the web for this information.