Relativity and the speed of light

In summary, this conversation is discussing how sound and light waves travel and how they are measured. The sound waves travel through the air and the light waves travel through the ether. The sound waves and light waves are measured to be the same for all observers, and there is no such thing as the ether.
  • #1
mrcotton
120
0
It is a general question just to boost my understanding
speedoflight_zps62f28a13.jpg


With a stationary boat both observers hear the horn at the same time as they are the same distance away from the horn.

In the bottom picture of the three pictures above:
If I make the boat move forward through the air at one block per time interval to the right, (the air is the medium the sound wave travels through). The observers are still the same distance away from the horn. The sound waves travel at two blocks per time interval in both directions.

So person 1 hears the sound in one time interval and person 2 hears the sound in 3 time intervals.

Is this above logic sound, (sorry)

speedoflight2_zps3877b0d0.jpg


But with light both observers see the light at the same time and record the same speed for the light wave as it has traveled the same distance to each in the same time interval.

Hope this all makes sense.
Is this logic so far correct.
Thanks
 
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  • #2
Your explanation for the sound is coorect

mrcotton said:
But with light both observers see the light at the same time
Yes. The two observers and the source are all in the same inertial frame, so there is nothing special whether the boat is moving or not.

mrcotton said:
and record the same speed for the light wave as it has traveled the same distance to each in the same time interval.
They will always measure the same speed of light: it is the one thing that is constant for all observers.

And there is no such thing as the ether...
 
  • #3
So this situation is ok for explaining that the light waves are not propagating through any medium. So no ether. I suppose I need to go off next and think about the Michelsom Morley experiment. If I understand correctly that experiment was set up to look for the ether. Thanks for your help Dr Claude
 

FAQ: Relativity and the speed of light

1) What is the theory of relativity?

The theory of relativity is a fundamental theory in physics that describes the relationship between space and time. It was developed by Albert Einstein in the early 20th century and has been tested and confirmed through numerous experiments and observations.

2) What is the speed of light?

The speed of light is a fundamental physical constant that represents the speed at which light travels in a vacuum. It is approximately 299,792,458 meters per second, or about 186,282 miles per second.

3) How does the theory of relativity explain the speed of light?

The theory of relativity states that the speed of light is the same for all observers, regardless of their relative motion. This means that no matter how fast an observer is moving, they will always measure the speed of light to be the same value. This is known as the principle of the constancy of the speed of light.

4) What is the relationship between the theory of relativity and time dilation?

The theory of relativity predicts that time is relative and can be affected by factors such as gravity and velocity. This means that time can appear to pass at different rates for different observers depending on their relative motion. This phenomenon is known as time dilation and has been confirmed through various experiments and observations.

5) How does the theory of relativity impact our understanding of the universe?

The theory of relativity has significantly impacted our understanding of the universe by providing a more accurate and comprehensive description of the laws of physics. It has also led to the development of various technologies, such as GPS, that rely on the principles of relativity. Additionally, the theory has played a crucial role in the study of cosmology and understanding the origins and evolution of the universe.

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