I wasn't questioning it's status as a real thing. I'm questioning (and this is directed toward N101N 🙂), it's 'practical/tangible' existence. Perspectives live in our mind, however useful they may be. But they are merely thought processes.
A photon entering a medium other than a vacuum encounters atoms. If it interacts with an atom aka is absorbed by it, it excites it (cue the entendres). The atom returns to it original pre-excitation state by re-emitting a photon. In the process, some of the photons energy is lost, and the the re-emitted photon is at a lower frequency (energy). This excite<>re-emit process slows down the passage of the photon through the medium. Once the photon exits the medium and back into a vacuum, it continues at c. But at a lower frequency.
It takes a photon emitted in the Sun’s core 1 million years to get to the surface. It starts out down there at energy levels equivalent to 15 million K and leaves the Sun at c. 5600 Kelvin.
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Sorry I didn make it clear. I'm pretty sure I understand why something's momentum diminishes when meeting a denser medium. You didn't address the part I am interested in. Why does a photon instantaneously accelerate when re-entering vacuum? Does it expend a power source to do this, and if so, where is the power source and mechanism?
If not, is it entering a different sort of space, that alters out perception of its speed?
It does not accelerate. It's already moving at c on emission. If it didn't, it wouldn't be light.
"Let there be light"
and it was
"Let there be light"
and it was
I thought I'd explained that.
Light does not actually slow down when it enters an optically denser medium.
The light travels at speed c in the vacuum outside of the medium and while travelling through the spaces (more vacuum) between the molecules of the medium.
The light only appears to travel more more slowly in the medium because its photons are absorbed then re-emitted by the molecules of the medium. This interaction with the molecules introduces a time lag to the passage of the photons through the medium.
Not once it re-emerges. Just at a lower frequency as Bonsai stated. You I'm sure are aware that sound travels at it's specified speed depending on sea level and air temp. It doesn't make any difference what frequency it's traveling at. It can be 1hz or 20khz, it will move at the same speed regardless. So when a photon re-emerges out of the said medium, it is for all intents and purposes, re-created albeit at a less than original frequency but nonetheless as effectual.
There are more complicated explanations for the slowing down of light when it enters an optically denser medium.
It's a hot topic for discussion, but none of the explanations that I've read make enough sense to me to summarise here!
Here's an example: Why do photons slow down and refract in transparent matters, specifically from a microscopic point of view? Have fun! 😀
It's a hot topic for discussion, but none of the explanations that I've read make enough sense to me to summarise here!
Here's an example: Why do photons slow down and refract in transparent matters, specifically from a microscopic point of view? Have fun! 😀
You and I have discussed GPS before in the 'black holes and white holes' thread! 😎
black holes and white holes
Read our contributions on pages 6, 7 and 8.
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Ok.... I forgot.
And I see I did not give the answer to: Why GPS position calculation needs data from 4 satellites.
Three is not enough because the receiver does not have a clock accurate enough, with no drift, as good as the clocks on board the satellites.
With 4 satellites you get with ultimate accuracy, the 3 coordinates and the time.
Well, our universe is 4 dimentional. A point actually has 4 coordinates: x,y,z,t.
And I see I did not give the answer to: Why GPS position calculation needs data from 4 satellites.
Three is not enough because the receiver does not have a clock accurate enough, with no drift, as good as the clocks on board the satellites.
With 4 satellites you get with ultimate accuracy, the 3 coordinates and the time.
Well, our universe is 4 dimentional. A point actually has 4 coordinates: x,y,z,t.
Is it reasonable to conclude that the existence of a singularity is a given considering the existence of black holes is now accepted as fact? If there 'must' be a singularity in the center of a black hole where compression renders matter to non-existent status, how could there be the possibility of another universe where physical laws are different? Going from existence to non-existence is absolute. Unless there could be a different definition for existence itself, we have deciphered the formula of it's requirements. So if there is another universe, it must then be subject to the same laws which we refer to as natural laws of science, no?
Well I went to page 6 and 7 of that link you provided.
I saw singularity mentioned. sheeesh 🙄
I saw singularity mentioned. sheeesh 🙄
It has been suggested that a singularity, which contains matter compressed to an infinite density, could become a Big Bang, creating an entire new universe within the black hole
If that is so, then the new universe might have slightly different physical properties from the one that made the black hole in the first place.
Liken that to the random mutation that allows a coronavirus to become a different strain.
Right, time for my beauty sleep and, boy, do I need it!
Wasn't the singularity a construct based on our math (Divide by zero)? One also could assume that a singularity is impossible based on the basic constants (Planck) in the universe and our quantum mechanics.
Do you always stay up til 4am? Insomnia?It has been suggested that a singularity, which contains matter compressed to an infinite density, could become a Big Bang, creating an entire new universe within the black hole
If that is so, then the new universe might have slightly different physical properties from the one that made the black hole in the first place.
Liken that to the random mutation that allows a coronavirus to become a different strain.
Right, time for my beauty sleep and, boy, do I need it!
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