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shivakumarvv75
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dear sir, light travels with constant speed of 3 x 10^8 m/s. does that mean light is in absolute motion irrespective of the its source?
I mean absolute motion as apposite of absolute rest.Orodruin said:What do you mean by ”absolute motion”?
shivakumarvv75 said:i need help in understanding physics as it is
With respect to what? Light has a constant relative speed of 299792458 m/s with respect to whoever is measuring it.shivakumarvv75 said:dear sir, light travels with constant speed of 3 x 10^8 m/s. does that mean light is in absolute motion irrespective of the its source?
shivakumarvv75 said:dear sir, light travels with constant speed of 3 x 10^8 m/s. does that mean light is in absolute motion irrespective of the its source?
True, but the question is not totally meaningless, if he re-states or edits it + the title. E.g. "can light be seen at rest?"PeterDonis said:Then you need to learn how to use its terminology correctly. In relativistic physics, there is no such thing as "absolute motion" or "absolute rest". So the question you are asking is meaningless.
But that's not what he means. We can give him a chance to restate ... He will learn in the process (from it) ...Dale said:I am with @PeterDonis on this. “Absolute X” usually refers to X as measured with respect to the absolute reference frame. Since that doesn’t exist the question doesn’t make sense.
Maybe not, but the only clarification he gave was “as apposite of absolute rest” which refers to being at rest in the absolute frame. So it may be exactly what he means.Stavros Kiri said:But that's not what he means.
He sais that he lacks knowledge of Physics (and perhaps confuses terminology). 'Absolute' as 'complete' is I think what he means (e.g. "complete motion" * vs "complete rest" *). Perhaps it's a problem of correct language too.Dale said:Maybe not, but the only clarification he gave was “as apposite of absolute rest” which refers to being at rest in the absolute frame. So it may be exactly what he means.
Ibix said:Light is always moving in all frames of reference, it is true.
I said that too. E.g.PeterDonis said:@Stavros Kiri please do not speculate on what the OP means. It's up to the OP to clarify his question.
It's a common students' misuse of terminology that I've seen with foreigner students.Stavros Kiri said:But, you're right. Unless he verifies those, there's nothing we can do ...
+ Welcome to PF and good luck in your Journey! ...shivakumarvv75 said:thank you sir.now I think I have joined the journey of understanding understanding physics.
I'm afraid there is no such a thing. I suggest that you first study thoroughly and validly the terms 'relative motion' versus 'absolute motion' as used in Physics/Mechanics/Relativity etc. .shivakumarvv75 said:can the inertial frame of reference with respect to center of universe be found?
Note also that we should add:shivakumarvv75 said:with the fact that speed of light is invariant
As far as we know there is no center of the universe. However, at every point there is a reference frame where the universe is isotropic.shivakumarvv75 said:sir, with the fact that speed of light is invariant, can the inertial frame of reference with respect to center of universe be found?
The universe doesn't have a centre, as far as we are aware. And, in fact, the meaning of "relativity" in the sense of the theory of relativity is that you can use any frame of reference you like, and no frame has any more significance than any other. A frame might be convenient for some particular task, but you can always use any frame.shivakumarvv75 said:sir, with the fact that speed of light is invariant, can the inertial frame of reference with respect to center of universe be found?
Is there always such an "isotropic" frame? Is is unique (at each point)? How would one know that he was in such a frame? I am truly unsure about all of the above...Dale said:As far as we know there is no center of the universe. However, at every point there is a reference frame where the universe is isotropic.
If our cosmological model is correct, yes.hutchphd said:Is there always such an "isotropic" frame? Is is unique (at each point)?
One would carefully measure the cosmic microwave background radiation. If there is no dipole anisotropy then one is at rest in that frame. If there is dipole anisotropy then you can use it to determine how fast and in which direction you are moving with respect to that frame.hutchphd said:How would one know that he was in such a frame?
However, there is the "CMBR Axis of Evil" (CMBR = Cosmic Microwave Background Radiation) ...Dale said:If our cosmological model is correct, yes.
One would carefully measure the cosmic microwave background radiation. If there is no dipole anisotropy then one is at rest in that frame. If there is dipole anisotropy then you can use it to determine how fast and in which direction you are moving with respect to that frame.
Stavros Kiri said:However, there is the "CMBR Axis of Evil" (CMBR = Cosmic Microwave Background Radiation) ...
Note that the axis of evil, even if it does exist, does not prevent the detection of the dipole anisotropy. It is a different form of anisotropy.Stavros Kiri said:However, there is the "CMBR Axis of Evil" (CMBR = Cosmic Microwave Background Radiation) ...
PeterDonis said:This is still being analyzed
Both well said! I do not disagree. It's still an open subject/problem. We have to wait for more evidence etc.Dale said:However, I am also skeptical without more evidence.
The velocity of light, denoted as c, is a fundamental constant in physics that represents the speed at which light travels in a vacuum. In other words, it is the maximum speed at which energy, information, and matter can travel through space.
The first successful measurement of the velocity of light was done by Danish astronomer Ole Rømer in the late 17th century. He observed the moons of Jupiter and noticed a time difference in their eclipses depending on the distance between Earth and Jupiter. This led him to estimate the velocity of light to be approximately 220,000 kilometers per second.
The velocity of light is a crucial constant in many fields of science, including physics, astronomy, and engineering. It serves as a universal speed limit in the universe and plays a vital role in theories such as Einstein's theory of relativity. It also helps us understand the behavior of electromagnetic radiation and has practical applications in technologies such as fiber optics and GPS systems.
According to the theory of relativity, it is impossible for an object to travel faster than the speed of light. As an object approaches the speed of light, its mass increases exponentially, making it more and more difficult to accelerate. Therefore, the velocity of light is considered to be the ultimate speed limit in the universe.
Absolute rest, also known as absolute rest frame, is a theoretical concept in physics that describes a state of complete rest or zero motion. It is a reference frame in which an object has zero velocity and is not affected by any external forces. However, since all objects are constantly in motion in the universe, the concept of absolute rest is not observed in reality and is only used as a theoretical reference point.