[jsaldea12 (OP)]

Because of Michelson-morley experiment that ight is any where it is pointed, the speed of light is186,000 miles  per second.thus it was concluded by the3 scientific world,,  including  Einstein, that light is independent from source.!!! Is that correct? What is the correct explanation. jsaldea 4.1.19 ,..

[alancalverd]

Once launched, any missile, be it a photon or a rock, becomes independent of its source - definition of a missile! As far as we know, several of the stars we "see" at night have died or moved long ago!

[jsaldea12 (OP)]

It is like this: A spaceship, moving  at speed of 100,000 miles per sec.,will have the same speed,whether, forward motion, backward motion, sideward motion.. In short, forward motion is 186,000 miles sec., rear motion still will move at 186,000 miles /sec.!! Why? jsa  4.1.19

[Colin2B]

It is like this: A spaceship, moving  at speed of 100,000 miles per sec.,will have the same speed,whether, forward motion, backward motion, sideward motion.. In short, forward motion is 186,000 miles sec., rear motion still will move at 186,000 miles /sec.!! Why? jsa  4.1.19

This was answered in the other thread, please read it https://www.thenakedscientists.com/forum/index.php?topic=76589.msg571399#msg571399

[Janus]

It is like this: A spaceship, moving  at speed of 100,000 miles per sec.,will have the same speed,whether, forward motion, backward motion, sideward motion.. In short, forward motion is 186,000 miles sec., rear motion still will move at 186,000 miles /sec.!! Why? jsa  4.1.19

It's a fundamental attribute of the way the universe works.  "Why?" questions like this, even when answered, just lead to another "why?" question.
Why does a ball when I'm throwing it keep moving forward after I let go and not just drop straight to the ground?
Because momentum is conserved.
Why is momentum conserved?
Due to Newton's Laws of motion.
Why do Newton's Laws of Motion hold true?...

After a point it just becomes fruitless to continue down the "Why?" rabbit hole, and is more productive to work out the consequences of the behavior.  "Why" the universe has a finite invariant speed built into it is a question we may never have an answer to.  But we can work out how the universe is expected to behave in given scenarios when taking this attribute into account.

Is it intuitive that I measure the speed of light as being c relative to myself no matter what speed the source is moving while at the same time the source measures it as moving at c relative to itself?  No.   But there is no rule that says the universe must obey my, or anyone else's, intuition.

[geordief]

  No.   But there is no rule that says the universe must obey my, or anyone else's, intuition.

Is there any hope or method whereby we might improve our intuition in this area?

Education,education,education perhaps?

[jsaldea12 (OP)]

Here is the answer: it is because the whole outer space has electro-magnetic property..that whereever it is tapped, switched, makes no difference whether the source  is moving forward, or at its rear, or at its  side, the light that source produces moves at same speed of 186,000 miles/sec. IN ALL DIRECTION BECAUSE THE WHOLE OUTER SPACE IS ELECTRO-MAGNETIC. 

[jsaldea12 (OP)]

light is never independent from source
« on: Today at 09:31:44 »
Here is the answer: it is because the whole outer space has electro-magnetic property..that whereever the source is tapped, switched, makes no difference whether the source  is moving forward,  its rear, its  side, the light that source produces moves at same speed of 186,000 miles/sec. in all direction, forward, rear, and sides!!.(Taken from article of undersigned:”Why gravity o earth is all attraction, no repulsion” ) jose s. aldea roxas 4.2.19

[evan_au]

the light that source produces moves at same speed of 186,000 miles/sec. IN ALL DIRECTION BECAUSE THE WHOLE OUTER SPACE IS ELECTRO-MAGNETIC.

I would prefer to say that all of space is filled with an electromagnetic field.
Light propagates at 186,000 miles/second because of the properties of this electromagnetic field.

And because of time dilation due to velocity and gravitational curvature of spacetime, all observers measure light at this speed in their own lab, regardless of what speed they are doing relative to each other, or where they are in a gravitational field.

[evan_au]

light is never independent from source

I would say that as soon as light has propagated away from the source, it becomes independent of the source.
- Far enough so it is "far field", and subject to the inverse square law
- Not "near field"

Once light has propagated away from the source, the source can change, without changing the characteristics of the emitted light. The source can:
- Stop transmitting
- Start transmitting at a different frequency
- Accelerate and change direction
- Move up or down in a gravitational field

...and none of this will change the characteristics of the light which has already been emitted.

So I would say that light rapidly becomes independent of the source - say when it has propagated more than 100 wavelengths away from the source.

[evan_au]

I merged 2 threads with the same title: " light is never independent from source".

Please don't create multiple threads on the same subject.
   Evan - moderator

[yor_on]

you're wondering why light always will be measured to have a same speed, no matter relative motion of source and/or observer. That's the first postulate Einstein made in SR, and from that time dilation's and LorentzFitzgerald contraction's came as a natural consequence.

It fits all observations, but we don't know why it behaves this way.

[geordief]

you're wondering why light always will be measured to have a same speed, no matter relative motion of source and/or observer. That's the first postulate Einstein made in SR, and from that time dilation's and LorentzFitzgerald contraction's came as a natural consequence.

It fits all observations, but we don't know why it behaves this way.

Could a universe be designed without this feature (the invariance of c) ?   Could there be (as a musing possibility ,not as observed) a universe where the speed of light (or c)  actually  depended on one's inertial frame of reference ?

Would contradictions show up? Would there have to be an "ether" of some kind?

Imagine you were building a universe from scratch** ...would the invariance of c appear in all models?

Any other features that would be essential?

**it would have to be a simulation  as any physical "new universe" would just be a sub set of this one.

[yor_on]

A good observation Geordef. It should have a importance.
=

You will have to make what is called a self consistent 'toy universe' and see where it takes you.