The speed of light

[m_m]

Hello to everyone.

I  have questions, if you don't mind me asking.

Are we moving or standing still in relation to light? And what about light in relation to the Earth? And what about the Earth in relation to light?

 

[iNow]

Just now, m_m said:

Are we moving or standing still in relation to light?

Light doesn’t have a valid rest frame so the question is meaningless. 

See also: How many times does zero go into Swiss cheese when doing division. 

[m_m]

Does light move?

[iNow]

Just now, m_m said:

Does light move?

By definition and it’s equally by definition never at rest 

[m_m]

Just now, iNow said:

By definition and it’s equally by definition never at rest 

So does the Earth. That's why I ask.

[Sensei]

Almost all matter emits photons and all matter absorbs photons. The question is at what energies/wavelengths/frequencies.

What is emitted with energy/wavelength/frequency f₀ from one object does not reach with the same energy/wavelength/frequency to another object, which is in a different reference system than the emitter.

 

https://en.wikipedia.org/wiki/Relativistic_Doppler_effect

Photons with inappropriate energies/wavelengths/frequencies can pass through matter treating it as a transparent object.

[Kassander]

49 minutes ago, m_m said:

Hello to everyone.

I  have questions, if you don't mind me asking.

Are we moving or standing still in relation to light? And what about light in relation to the Earth? And what about the Earth in relation to light?

 

This question deals with the core of the theory of relativity. According to Einstein, light in a vacuum always travels at the same speed, regardless of whether the light source or the observer is moving. That is why the theory of relativity is called the theory of relativity. So from the point of view of an observer, light always moves at the speed of light.

In relation to light: From our perspective, light always travels at the speed of light. This is a fundamental property of the universe and does not depend on our motion relative to other objects.

In relation to the Earth: The Earth is moving through space, both orbiting the Sun and traveling within the Milky Way. However, this motion does not affect the speed of light relative to us because the speed of light remains constant for all observers.

In relation to ourselves: Whether we are moving relative to other objects or standing still, we always observe light traveling at the same speed. This is the core principle of the special theory of relativity: the speed of light is constant for all observers, regardless of their relative motion.

Edited Sunday at 05:22 PM by Kassander

[m_m]

Just now, Sensei said:

Almost all matter emits photons and all matter absorbs photons. The question is at what energies/wavelengths/frequencies.

What is emitted with energy/wavelength/frequency f₀ from one object does not reach with the same energy/wavelength/frequency to another object, which is in a different reference system than the emitter.

 

https://en.wikipedia.org/wiki/Relativistic_Doppler_effect

Photons with inappropriate energies/wavelengths/frequencies can pass through matter treating it as a transparent object.

So, does the Earth move or stand still in relation to light?

[iNow]

2 hours ago, m_m said:

So does the Earth.

False. Frame of reference for earth is valid. Frame of reference for light is not. 

1 hour ago, m_m said:

So, does the Earth move or stand still in relation to light?

Undefined since light isn’t a valid reference frame.

Again, you may as well be asking: “How loud is potato divided by zero, and express the answer in units of Celsius”

Edited Sunday at 06:46 PM by iNow

[swansont]

2 hours ago, m_m said:

So does the Earth. That's why I ask.

Movement is always in relation to some reference. The earth moves relative to the sun, for example. The earth does not move relative to some building resting on its surface.

Light moves relative to any object in an inertial frame of reference. Because light does not have some fixed frame of reference, asking if the earth moves relative to light can be problematic; you can say it does, relative to any photon, but since photons can move in different directions, “in relation to light” suffers from being too vague of a statement.