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cobrastrike
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Is it possible to go faster than the speed of light? And why do some scientists say you can't?
Thanks -_-!
Thanks -_-!
cobrastrike said:Is it possible to go faster than the speed of light? And why do some scientists say you can't?
Thanks -_-!
DaveC426913 said:Nothing with mass can accelerate to the speed of light. The closer you get to it, the more energy it will take to get closer. It is an asymptotic limit.
No, this does not follow.Cosmos2001 said:Hence, anything without mass can be faster than light: velocity of phase/group of EM waves, gamma-ray burst, neutrinos,
Light does not accelerate. It is emitted at c.Cosmos2001 said:and also initial acceleration of light (m/s² → v/t ), light’s initial acceleration shouldn’t exceed an acceleration of c (v/t), but it exceeds because it has no mass.
It can't.Cosmos2001 said:Extending this thought, if something has no mass then it can be faster than light,
No. Fields are pervasive - as in: they already exist everywhere. Changes to those fields are propogated at the speed of light.Cosmos2001 said:hence I thought it is logic the theory, that is said already observed in practice, that static fields (magnetic and electric) are at least 20 billion times faster than light.
Cosmos2001 said:As well, http://www.youtube.com/watch?v=Z8Hwqg9_oA8", which can be mathematically verified (f≥c/L)
Acceleration is the rate of change of velocity over time (∆v/∆t), hence, how could the light be emitted, with instantaneous speed up to c, without initial acceleration?DaveC426913 said:Light does not accelerate. It is emitted at c.
From what I have understood, then, is there a kind of “slot” that always travels at c, independently whether it is occupied by a photon or not?f95toli said:Because light does not follow the usual "rules" that apply for e.g. footballs. Light just "is" and always travel at c.
(a more scientific answer is that a photon is just an excitation of a tempora-spatial mode, i.e. that mode -which "travels" at c- either is or isn't occupied)
T=0 therefore v/t= undefinedCosmos2001 said:Acceleration is the rate of change of velocity over time (∆v/∆t), hence, how could the light be emitted, with instantaneous speed up to c, without initial acceleration?
FredT said:A friend of mine posed the question that if light is affected by the gravity of a black hole, couldn't the slingshot effect accelerate light?
Dremmer said:Yes, it is. Space does it all the time.
Cosmos2001 said:From what I have understood, then, is there a kind of “slot” that always travels at c, independently whether it is occupied by a photon or not?
I think it is not undefined; it is infinity.russ_watters said:T=0 therefore v/t= undefined
Cosmos2001 said:I think it is not undefined; it is infinity.
v/t ⇒ S/t²
lim (1/t²) = +∞
t→0
http://en.wikipedia.org/wiki/List_of_limits#Simple_functions
However, observers experience time. Would an observer see an emitted photon as it had acquired instantaneous velocity c in a time close to zero, observing infinity acceleration?DaveC426913 said:Regardless, the photon moves at c and only c. Photons do not experience time.
Cosmos2001 said:However, observers experience time. Would an observer see an emitted photon as it had acquired instantaneous velocity c in a time close to zero, observing infinity acceleration?
In quantum electrodynamics, yes. The state of a traveling photon always exists. When you "create" a photon, you merely excite that state. That's called the second quantization of electromagnetic field. So in a way, looking at it as something that always travels at c and you simply flip it on and off is consistent with our understanding of electromagnetic wave.Cosmos2001 said:From what I have understood, then, is there a kind of “slot” that always travels at c, independently whether it is occupied by a photon or not?
K^2 said:Just keep in mind that you're getting very close to the slippery edge of a rabbit hole that is quantum gravity.
DaveC426913 said:Light does not accelerate. It is emitted at c.
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AdkinsJr said:hmmmm, that's interesting. So if light is slowed down as it passes through a medium, does this mean that it isn't accelerating although there's a change in velocity? That's rather strange to me...
If light can't accelerate, then forces cannot act on light, is that true? The definition of a force (as I know it) is something that causes an acceleration...
In medium, the actual photons still travel at the speed of light. They are simply constantly absorbed and re-emitted. That gives you phase shifts equivalent to light wave slowing down. So the particles never decelerate. I know it sounds like a dirty fix to a serious problem, but it was invented by nature, not scientists.AdkinsJr said:hmmmm, that's interesting. So if light is slowed down as it passes through a medium, does this mean that it isn't accelerating although there's a change in velocity? That's rather strange to me...
If light can't accelerate, then forces cannot act on light, is that true? The definition of a force (as I know it) is something that causes an acceleration...
Infinity is not a number - that's why it is undefined.Cosmos2001 said:I think it is not undefined; it is infinity.
v/t ⇒ S/t²
lim (1/t²) = +∞
t→0
http://en.wikipedia.org/wiki/List_of_limits#Simple_functions
Acceleration is a change in the vector velocity. it can be a change in speed (the magnitude of the velocity vector) or a change in direction (or both). Light always travels at speed c. Acceleration can only change its direction.FredT said:A friend of mine posed the question that if light is affected by the gravity of a black hole, couldn't the slingshot effect accelerate light?
Excuse me, but always I read it; it sounds like dogmas to me that cannot be proven or disproven."Nothing with mass can accelerate to the speed of light. The closer you get to it, the more energy it will take to get closer. It is an asymptotic limit."
"No. Anything with no mass travels AT the speed of light. E.g. light."
"Light does not accelerate. It is emitted at c."
"Regardless, the photon moves at c and only c. Photons do not experience time."
"As I mentioned earlier, the individual photons still travel at c."
"In medium, the actual photons still travel at the speed of light."
Your ignorance of the experimental results does not imply that the experimental results do not exist. See the sticky on the experimental basis of SR for a good concise overview. Many experiments involve high speed neutrinos and neutrons from various nuclear reactions, so your assertions about only using charged particles are incorrect. There are also experiments with large objects like satellites and planes which are also electrically neutral.Cosmos2001 said:it sounds like dogmas to me that cannot be proven or disproven.
Well, the minimum amount of energy required to accelerate a neutron close to speed of light:DaleSpam said:Your ignorance of the experimental results does not imply that the experimental results do not exist. See the sticky on the experimental basis of SR for a good concise overview. Many experiments involve high speed neutrinos and neutrons from various nuclear reactions, so your assertions about only using charged particles are incorrect. There are also experiments with large objects like satellites and planes which are also electrically neutral.
Is this your attempt to overturn the "dogma" that massive objects cannot reach or exceed c?Cosmos2001 said:Well, the minimum amount of energy required to accelerate a neutron close to speed of light:
neutron=1.67493×10-27 kg
c=299792458 m/s
E=½mv²
EJ=½(1.67493×10-27)(299792458)² =75.26760×10-12J
EeV=75.26760×10-12/1.60218×10-19 = 469.78242×106 = 470MeV
The average energy released in fission of one Pu-239 atom is 210MeV, emitted neutrons 5.9MeV which is very far from 470MeV, there is not enough energy to emit neutron close to speed of light.
http://en.wikipedia.org/wiki/Plutonium-239#Nuclear_properties
My question is: are there atomic nucleuses that emit neutrons having kinetic energy exceeding 470MeV?