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ArthurTX

Mysteries of the Sun

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I was just wondering and it's been bugging me for a long time.
We know gravity affect time and the strongest source of gravity is the sun in our solar system. 
If the sun photons from the center takes thousands of years to escape the Sun's gravity, we have to assume
time is slower at the center of the Sun than at the edge. If that is so, is that why it's taking so long
for the particles to escape the Sun because they're at a slower time rate than normal space. (Scientist say it's gravity)
As the particles escape the Corona sphere there is a phenomenon where the temperature is at
its highest. Could this be because time is becoming normal so that their particles produce 
the most heat at the edge of the sun's hemisphere?
Just my thoughts on the mysteries of the Sun.
 

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Hi Arthur,

Time might be slower, but what about length contraction?. Lorentz factor which slows time is the same factor for length contraction

Just a thought from my side too :)

 

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The Sun's gravity is very mild in cosmic terms and hardly affects time and space. Photons only take a long time to reach the surface because there's a lot of hydrogen in the way, so the photons bounce about randomly.

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3 minutes ago, Ags said:

The Sun's gravity is very mild in cosmic terms and hardly affects time and space. Photons only take a long time to reach the surface because there's a lot of hydrogen in the way, so the photons bounce about randomly.

Isn't "C" a constant?. Should it matter what medium carries them?

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Firstly, c varies according to medium - that's how refractors work. The figure for c is the speed of light in a vacuum.

Secondly, the light in the sun is still going nearly that fast, but it is taking a very long route, not a straight line.

Edited by Ags

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6 minutes ago, Ags said:

Firstly, c varies according to medium - that's how refractors work. The figure for c is the speed of light in a vacuum.

Secondly, the light in the sun is still going nearly that fast, but it is taking a very long route, not a straight line.

Thanks for the elaboration ?

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I have a picture of it being the density of particles in the core/radiative zone that causes the photons to take so long to make it to the photosphere, not gravity. As Agnes writes above, ‘there’s a lot of hydrogen in the way’ and the photons interact with other particles as they meet.

Your walk round the block takes longer if it’s crowded and you keep meeting other people. Similar for the photon. Not so much to do with time being slowed, more to do with lots of obstacles to get past.

p.s. Welcome to SGL, Arthur.

Edited by Floater
Clarify radiative zone
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There's an excellent program explaining all this in the Discovery Channels " How the Universe Works " series, they usually show up on Y'Tube eventually.

Dave

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7 hours ago, Floater said:

I have a picture of it being the density of particles in the core/radiative zone that causes the photons to take so long to make it to the photosphere, not gravity. As Agnes writes above, ‘there’s a lot of hydrogen in the way’ and the photons interact with other particles as they meet.

Your walk round the block takes longer if it’s crowded and you keep meeting other people. Similar for the photon. Not so much to do with time being slowed, more to do with lots of obstacles to get past.

 

I would bet this is bang on,  i'm pretty sure the phenomenon of time dilation is directly related to speed, and not gravitational pull.

Photons making their way out of the sun are like someone finding their way out of the Amazon, with a blindfold on, banging into trees a million times, before by chance, finally exiting.

Edited by Sunshine
typo
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2 hours ago, Floater said:

Your walk round the block takes longer if it’s crowded and you keep meeting other people. Similar for the photon. Not so much to do with time being slowed, more to do with lots of obstacles to get past.

Indeed. As far as I am aware, the estimates of how long it takes photons to travel from the sun's core is not even based any direct measurement. It is calculated based on our knowledge of the physical properties of the medium it has to travel through and our understanding on how photons interact with matter.   In fact there is so much interaction going on through absorption/emission/elastic and inelastic energy exchange etc that the (visible) photons which exit the sun cannot in any real sense even be considered to be the same (gamma ray) ones that left the core. 

Robin

 

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11 hours ago, Ags said:

The Sun's gravity is very mild in cosmic terms and hardly affects time and space. Photons only take a long time to reach the surface because there's a lot of hydrogen in the way, so the photons bounce about randomly.

Yes!

Here's a helpful illustration:

P1060406.JPG

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The constancy of light is due to the fact that all observers (regardless of their own velocity) will measure light as travelling at the same speed. The actual figure they record will change depending on what medium the light is travelling thorough.  It travels slower through water, which is why you see the "broken" straw effect.

You are correct that gravity causes time dilation,  but as mentioned above,  it's due to it being a crowded place in the core of the sun. The photon itself doesn't experience the passage of time,  due to the fact that it is travelling at the speed of light. 

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Could only find this in this wide screen format or a version with faulty sound

Dave

 

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There seems to be some confusion in this thread with different effects getting mixed up.

In GR variations in the curvature of space time do indeed cause time dilation. They are normally mixed together but can be separated in simple cases.

Firstly, light travelling from the bottom of a building on earth in a vacuum will be red shifted due to the lower gravity at the top compared to the bottom. (Clock runs slower at the bottom compared to those at the top)

Secondly, light from a distant source will be red shifted due to the metric expansion of space in our expanding universe. (This is not normally taken as a change it clock rate but as metrical expansion.)

Thirdly,  light can be red or blue shifted as the emitter move through space-time with a velocity relative to the receiver - Relativistic Doppler effect, but this includes a time dilation effect due to the clocks moving relative to each.

Fourthly, in a medium of refractive index n the speed of light is reduced to c/n and will have a different wavelength compared to that in a vacuum 

These effect are real and the first and third need to be taken into account to make the GPS system work accurately.

However, none of these has a significant effect on the time it take the energy released in the form of gamma rays in the solar interior to reach the top of the photosphere.  Robin explains it well here.

17 hours ago, robin_astro said:

Indeed. As far as I am aware, the estimates of how long it takes photons to travel from the sun's core is not even based any direct measurement. It is calculated based on our knowledge of the physical properties of the medium it has to travel through and our understanding on how photons interact with matter.   In fact there is so much interaction going on through absorption/emission/elastic and inelastic energy exchange etc that the (visible) photons which exit the sun cannot in any real sense even be considered to be the same (gamma ray) ones that left the core. 

 In effect the em radiation does a random walk (with a very short mean free path between interactions) as it diffuses outward from the core under the thermal gradient from core to surface, before finally getting into "free" space.  

In addition some of the light emitted from the photosphere is carried toward the surface by other mechanisms e.g. convection.

Regards Andrew

Edited by andrew s

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On 02/08/2018 at 19:36, ArthurTX said:

I was just wondering and it's been bugging me for a long time.
We know gravity affect time and the strongest source of gravity is the sun in our solar system. 
If the sun photons from the center takes thousands of years to escape the Sun's gravity, we have to assume
time is slower at the center of the Sun than at the edge. If that is so, is that why it's taking so long
for the particles to escape the Sun because they're at a slower time rate than normal space. (Scientist say it's gravity)
As the particles escape the Corona sphere there is a phenomenon where the temperature is at
its highest. Could this be because time is becoming normal so that their particles produce 
the most heat at the edge of the sun's hemisphere?
Just my thoughts on the mysteries of the Sun.
 

Hey, Arthur! Where you gone? ??

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