Speed of light pulse if you have a velocity of c

In summary, the concept of a light pulse being emitted in an inertial frame while the observer is moving at a constant velocity of c away from the pulse and initially 10m away from it may seem illogical, but it is actually inevitable due to the fact that the speed of light is invariant in all inertial frames. Whether the light pulse will reach the observer or not depends on their relative positions and movements, but the velocity of the light will always be measured as c regardless.
  • #1
ed2288
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Homework Statement



A light pulse is emitted in an inertial frame. You are moving at a constant velocity of c AWAY from the pulse, and initially 10m away from the pulse. Will the pulse reach you, and what velocity will you measure for c?



Homework Equations





The Attempt at a Solution



Well I know that c is invariant in inertial frames so I'm going to say yes the pulse will reach me and it'll be traveling at velocity c, but surely this is the most illogical answer ever? My classical brain wants to say, No the pulse will not reach me and will remain 10m away. Any thoughts? Thanks
 
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  • #2
Who wrote this?? :confused:
ed2288 said:
A light pulse is emitted in an inertial frame.

This makes no sense.

Nothing happens in a frame.

A frame is what you observe things from. The same thing can be observed from every possible frame (both inertial and non-inertial). This light pulse, however it was created, can be observed in every possible frame.
You are moving at a constant velocity of c AWAY from the pulse, and initially 10m away from the pulse.

This is the opposite of making no sense. This is so inevtiable true that it contains no information at all. Your speed will always be c relative to light. And if you're moving away from the light, then it's moving away from you.
 
  • #3
But how is it possible for the light pulse to catch up to you if you're 10m ahead of it and both traveling a c?
 
  • #4
Just to clarify, by light pulse, I mean for example a bulb is switched on and off sending out a sphere of light.
 
  • #5
ed2288 said:
Just to clarify, by light pulse, I mean for example a bulb is switched on and off sending out a sphere of light.
ed2288 said:
But how is it possible for the light pulse to catch up to you if you're 10m ahead of it and both traveling a c?

You can't travel at c relative to the bulb.

The light travels at c relative to everyone. It inevitably travels at c relative to you, and you inevitably travel at c relative to it, even if you're just standing there.

Assuming the bulb emits light in only one direction, it will either miss you or hit you, and it will only hit you if you're in the way! :rolleyes:
 

1. What is the speed of light pulse if you have a velocity of c?

The speed of light pulse, or electromagnetic radiation, is always traveling at the speed of light in a vacuum, which is approximately 299,792,458 meters per second. This is known as the universal speed limit and is denoted by the symbol "c". No matter the observer's frame of reference or velocity, the speed of light remains constant.

2. How is the speed of light pulse determined?

The speed of light pulse is determined by the fundamental properties of electromagnetic waves, such as wavelength and frequency. These properties are related by the formula c = λν, where c is the speed of light, λ is the wavelength, and ν is the frequency. This relationship was first derived by physicist James Clerk Maxwell in the 19th century.

3. Can anything travel faster than the speed of light pulse?

According to the current laws of physics, nothing can travel faster than the speed of light. This is because as an object's velocity approaches the speed of light, its mass and energy increase exponentially, making it impossible to reach the speed of light. This is known as Einstein's theory of special relativity.

4. How does the speed of light pulse compare to other forms of energy?

The speed of light pulse is the fastest known form of energy and is often used as a benchmark for measuring the speed of other objects. For example, the speed of sound in air is much slower, at approximately 343 meters per second. The speed of light is also much faster than other forms of electromagnetic radiation, such as radio waves or microwaves.

5. What practical applications rely on the speed of light pulse?

The speed of light pulse has many practical applications, such as in telecommunications, where it is used to transmit information through fiber optic cables. It is also crucial in astronomy, as it allows us to measure the distance between celestial objects. Other applications include laser technology, medical imaging, and even the measurement of time through atomic clocks.

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