how many phases can light propagate, and would it travel faster or slower in some of them?
211982
Greetings,\n\nKinda outta my league, but perhaps the link I posted can be of some use to you.\n\nDiscover had an article last year about a couple of inflation cosmology theorists who believed the speed of light, while constant now, was not constant in the very early universe, it was in fact slower.  Not sure about all that, but thought you might want to go digging for the article.\n\n-matt
502472
There are basically 4 theories of light\n\n01. The Corpuscular Theory of Light\n02. The Wave Theory of Light\n03. The Electromagnetic Theory of Light\n04. The Quantum Theory of Light\n\n\n01. The Corpuscular Theory of Light\n-----------------------------------------------\nNewton proposed this theory that treats light as being composed of tiny particles. We use this theory to describe reflection.   While the theory can explain the primary and secondary rainbows, it cannot explain the supernumerary bow, the corona, or an iridescent cloud.\n\n\n02. The Wave Theory of Light\n---------------------------------------\nProposed by Huygens, this theory describes light as waves that spread out from the source that generates the light.   Each color is a different wavelength. Supernumerary bows are explained by assuming that light is a wave.\n\n\n03. The Electromagnetic Theory of Light\n----------------------------------------------------\nMaxwell's theory describes light as having electric and magnetic properties--electromagnetic waves. It is an improvement over the wave theory in that it explains how light is generated.   Visible light is only one type of electromagnetic wave. This theory is very math intensive.\n\n04. The Quantum Theory of Light\n-------------------------------------------\nThis theory is more mathematical than Maxwell's equations! It is similar to the corpuscular theory of Newton, except that instead of describing light as particles, light is composed of 'packets of energy' or photons. The energy of the photon determines the color \n\nThe dual theory of light says that it has corpuscular as well as wave properties.\n\nThe speed of light is determined as follows\nVelocity = Frequency x Wavelength\n\nTransparent Objects are  those which pass light through them. Opaque objects are those which doesn't pass light through them.  Translucent objects are between them.
123758
I'm sure you are spekaing strictly hypothetically, but don't forget the closer you get to the speed of light (c), the slower time moves around you.  So if you were to go like 90% of c for 1 year, more than 1 year would pass for everyone else.
4945
It's true that the speed of light is constant no matter what speed at which you or the source is moving.  This is a fundamental postulate of relativity, and there is no explination.  It's just accepted because our experiments indicate that it is true.  You used the formula "lights speed + X = actual speed"  this type of velocity addition is called "Galilean".  It turns out that speeds don't actually add that way.  Far out.\n\nWhere is the rest of the energy? Good question.  The frequency of the light you observe from the sun DOES depend on how fast you and it are moving.  The energy of each photon is given by E = hf, where f is the frequency of light.
25100
to answer your question it is possible to go faster the the speed of light. The speed of light is 186,000 miles per second.\n\nIf zooming beyond the local speed limit is punishable by law, then some scientists may have a gargantuan speeding ticket to pay. \n\nIn a controversial experiment reported in this weeks journal Nature, scientists at the NEC Research Institute in Princeton, New Jersey claim to have broken the ultimate speed limit -- the speed of light. Though hotly contested, some say this achievement could dramatically increase the speeds at which we can send and receive information. \n\nTaught in physics classes the world over, Albert Einsteins theory of special relativity holds that no object or information can move faster than the speed of light in a vacuum, or 186,000 miles (300,000 kilometers) per second. But NECs Lijun Wang says he created an experiment in which a light beam raced through a gas-filled chamber so quickly, it exceeded the speed of light by a factor of 300. Whats more, the light pulse appears to have left the confines of the chamber before it even entered a seemingly impossible occurrence according to theories of causality, which predict that causes must always precede their effects. \n\n"It sounds crazy, but this can actually occur," said Raymond Chiao, a physicist at the University of California at Berkeley. Chiao, one of a group of researchers who have been working to break the speed-of-light limit, explained that although a common object such as a baseball could never be flung faster than the speed of light, pulses of energy with certain complex properties have been known to bend the rules. \n\n\n\n"It sounds crazy, but it actually can occur." \n\n\n\n\nIn fact, several recent experiments, including one done by Chiao earlier this year, have pointed to energy pulses zooming faster than light speed. Yet each of these experiments has been encumbered by severe limitations on measurement or observation of the energy pulses. In contrast, this latest experiment is being touted by some as the most dramatic example yet of light breaking its own speed barrier. \n\n"The effects are much larger and more spectacular" than previous observations, said Chiao. \n\nIn Wangs experiment, a pulse of light passed through a small chamber filled with atoms of elemental cesium. A light beam traveling through such a medium has two different velocities a velocity for the individual light waves in the beam and a group velocity for the entire beam. Oddly, some light waves in the beam can actually travel backward for miniscule amounts of time, creating a sort of "tail" behind forward-moving waves. As such, a light wave and its tail can leave the gas cavity at different times, creating the effect that the light beam has left the cavity before its even entered. \n\nConfused? Youre not alone. In fact, even scientists who are familiar with this area of study are unsure about the details of Wangs experiment. And many scientists said the experiments results are still open to interpretation. \n\nWilliam Happer, a physicist at Princeton University argued that several specific problems exist with the experiment, including the fact that pulses get distorted when passed through any media other than a vacuum, or empty space. In addition, he said Wang and his colleagues performed the experiment in a way that doesnt tell the whole story, and that it can be interpreted incorrectly. "This is anything but dramatic," said Happer. "If you look at the data, theres essentially no evidence that [the beam] is going faster than the speed of light." \n\nWhats more, most scientists agree that even if such a beam can be proved speedier than light, it would probably not be able to carry any information. Such a feat could conceivably allow data to be sent back in time, thus violating laws of causality and sending quantum physics into disrepair. \n\nOthers are more optimistic as to the possible
416276
In theory, yes.  Because the light particles that were traveling slower than you would have been slower.  Very good question.  However, speeding past the speed of light would mean the fundamentals of E = Mc^2, would cease to make sense.
554672
I think I understand your experiment.  I'm standing at the anulus observing.  I see the light from the lighthouse.  Exactly one second later, I see the next flash of light from the lighthouse, no matter the radius of the anulus.  To satisfy (1) the perimeter of the anulus must be 186,000 miles, the diameter 186,000 miles / pi or 59,206 miles, and the radius d/2 = 29,603 miles.  That's about 7.47 times the earth's radius.  For (2), if you double the radius, you double the circumference.  Keeping the time the same, that doubles the speed.  You already knew that.\n\nFor (3), at the lighthouse you see the reflection of the lighthouse beam.  To reduce confusion, you could do what real lighthouses or bouys sometimes do:  alternating rotations are a different color.  But what you would see is the reflection, but delayed by 1/pi seconds, or 318 milliseconds.\n\nI'm guessing at your response.  At z=2D, this 'intersection' is travelling at twice the speed of light.  There's no physics problem with that.  It's not conveying either matter or information faster than the speed of light.  You have just contrived two events closer in time to each other than the time light would take to go between them.
655326
#1: It doesn't. The frequency of a beam of light remains constant regardless of the medium through which it travels, although the wavelength may change.\n#2: Absolutely nothing, for the same reason as #1.\n#3: Not for a mirror. The focal length of a mirror is determined by reflection, not refraction, and the angle of reflection is equal to the angle of incidence, regardless of the medium.\n#4: 1:1. The velocity of light does not depend on wavelength*\n\n*okay, for some materials the index of refraction, and therefore the speed of light in that material, depends slightly on wavelength, which is why a prism can be used to separate light into its various colors. However, the question did not specify a particular medium, so I assumed it meant in vacuum, where the velocities of all light rays are indeed the same.
410980
Frequency = velocity of propagation / wavelength.\n\nFor light, we assume it is moving in a vacuum, so vp is 3e8 m/s.  The wavelength of 310nm is 310e-9 meters.  Then we plug the numbers in, and we get (3e8 m/s) / (310e-9 m) = 967.742e12 Hz because 1/s is the same as cycles/sec, which is a Hertz.
238090
The atmosphere is made up of several layers,each one with a varying density.Thus,the speed of light differs in different layers of the atmosphere and the light gets refracted(deviated from its path when it travels from one medium to another)when passing from one layer of atmosphere to another.Due to this refraction of light in the different layers of the atrmosphere,stars appear to twinkle
645535
The proof is red-shift.\n\nAs things recede from each other at a high fraction of c (speed of light), the waves stretch out; visible light takes on a higher red content.  The SPEED of light remains the same, but the frequency changes.\n\nConversely, when things approach each other, they blue-shift; the light becomes more blue.
136919
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/fast_light.html\n\nhave a look at this website
263348
with travelling electrons.depending on their wavelength,colours are formed
40042
Yeah I think you misread what scientists "say".  In the equation, the speed of light is inversly proportional to mass.  So the faster something is, the more infinitly small in mass it has to be.  Light is measured in particles called photons, that have 0 mass.  Since everything we see has a mass, it can never go the speed of light which has none.  Oh and is light really that fast?  It takes 8 minutes for a photon from the sun to get here.  And yeah, photons Smash into us all the time.  Its a whole quantum chemistry thing, but you can feel the warmth of the sun on your skin.  Thats cuz your being bombarded with light.
66960
>>>>why can nothing excede the speed of light?\n\nLots of things can and do exceed the speed of light.\n \nNo information or mass can exceed the speed of light. Why? Because the speed of light is our one reference point. If anything exceeded the speed of light it would arrive at its destination BEFORE it was sent.\n\nIt's exactly like recieving a letter the day before it is written. It's impossible and  it makes no real sesne to ask why it can't happen. Cause has to preceed effect.\n\n>>>>if radio waves are slower than light\n\nRadio waves are just electromagnetic radiation. They travel at lightspeed just like all other EMR.\n\n>>>>>then wouldnt gama and X rays be faster?\n\nNo, they also travel at C. They just have higher freqencies.\n\n>>> or do all waves travel at the same speed and the light >>> part is just a term\n\nWaves have all sorts of speeds. \nOcean waves travel at variable speeds, often les than 10  kms.hr. \nSound waves travel at a bit over 1000km/hr. \nLight waves travel at the speed of light.\n\n_______________\nInfinity said:"By the way, the quote "Lots of things can and \n>>>>>>do exceed the speed of light" is entirely false.\n\nI really, really wish people would do some basic research before attempting to adress points they clearly don't understand.\n\nThe expansion of the universe itself is faster than the speed of light (see the link below).\n\nAnd as wd5gnr and Hound both said it is perfectly possible for non-information bearing events to propagate faster than lightspeed. We recently had an in depth discussion on the experiments which have managed to produce pahse vlocities hundreds of times faster than light.\n\nAnd of course there are many many other events that travel at speeds well in excess of C.\n\nReally Infinity, you should at least take the time to do some research before correcting others. It saves you embarassment of this kind. More importantly it prevents you misleading others and spreading your ignorance.
550857
light is (in a nutshell) waves of energy. Waves (in general) travel in a straight line. stars are so far away that not much of their energy or waves hit the planet.
677105
Light always travels at the same speed in a vacuum, the speed changes ever so slightly when it has to go through a different medium (water e.g.) but its so fast to begin with you wouldn't really notice it. 300,000 kilometers per second is beyond human comprehension, I mean you can only imagine how fast that is, you can't experience it or 'know' it.