Light & Space: Investigating the Unknown

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SUMMARY

This discussion centers on the nature of light and gravity, specifically addressing the misconception of aether as a medium for light travel. The Michelson–Morley experiment definitively disproved the existence of aether, establishing that light does not require a medium to propagate. The conversation also explores the concept of spacetime, emphasizing that gravity results from the curvature of spacetime rather than a physical medium. Observations of light behavior and gravitational lensing provide strong evidence for these theories, reinforcing the understanding of light's consistency across vast distances.

PREREQUISITES
  • Understanding of the Michelson–Morley experiment
  • Familiarity with the concept of spacetime in general relativity
  • Knowledge of gravitational lensing and its implications
  • Basic principles of light propagation and electromagnetic waves
NEXT STEPS
  • Research the implications of the Michelson–Morley experiment on modern physics
  • Study gravitational lensing and its applications in astronomy
  • Explore the concept of spacetime and its role in general relativity
  • Investigate the speed of light and experiments verifying its constancy in a vacuum
USEFUL FOR

Physicists, astronomy enthusiasts, students of general relativity, and anyone interested in the fundamental principles of light and gravity.

  • #61
like I said earier, I'm thinking bigger than my tiny brain can handle. thank you for the info you have shown me
 
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  • #62
You might find this is interesting,
 
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  • #63
john-of-the-divine said:
. if you can explain, without math, exactly what causes the effect of gravity and how it effects light, I will understand
I cannot explain it without math. What good reason could you possibly have for rejecting a valid answer simply on the grounds that it contains math?

john-of-the-divine said:
. if you can't explain without numbers, then what makes the math so infallible?
Because the math accurately predicts the results of our best physical experiments and astronomical observations. How do you expect to predict something quantitative without math?

john-of-the-divine said:
just because the math works doesn't make it anything less then a best guess
That is why we do experiments too. To ensure that the math correctly describes part of nature.

john-of-the-divine said:
I just wanted to know how do you know %100
"100%" is math. So you can clearly do some math

john-of-the-divine said:
like I said, we won't know for sure till we go out there and look.
And when we do go out there and look we will have to use math to understand what we see.

Frankly, your anti math stance just comes off poorly here. If you don't want to learn math, that is fine, but don't delude yourself into thinking that an answer doesn't exist when you are simply unwilling to learn it. The deficiency is not in the answer.
 
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  • #64
rootone said:
You might find this is interesting,

I'm deffenetly going to finish that later. thanks
 
  • #65
Dale said:
I cannot explain it without math. What good reason could you possibly have for rejecting a valid answer simply on the grounds that it contains math?

Because the math accurately predicts the results of our best physical experiments and astronomical observations. How do you expect to predict something quantitative without math?

That is why we do experiments too. To ensure that the math correctly describes part of nature.

"100%" is math. So you can clearly do some math

And when we do go out there and look we will have to use math to understand what we see.

Frankly, your anti math stance just comes off poorly here. If you don't want to learn math, that is fine, but don't delude yourself into thinking that an answer doesn't exist when you are simply unwilling to learn it. The deficiency is not in the answer.
I'm not necessarily anti math, and I'm not unwilling to learn it, i was just looking for explanations that don t evolve math. sorry to waste your time. thank you for at least trying.
 
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  • #66
john-of-the-divine said:
I'm not necessarily anti math, and I'm not unwilling to learn it, i was just looking for explanations that don t evolve math. sorry to waste your time. thank you for at least trying.
To be quite blunt, trying to accurately explain physics without math is like trying to explain the color green to a blind person.
 
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  • #67
You have to take maths into the picture.
Maths is the car which shall make your physics ride more interesting and comfortable
To get to the point:
Photons have energy and energy generates gravity according to general relativity. However the gravity force is an extremely weak force for small objects, so for the gravity between individual elementary particles or between photons the force of gravity would be completely negligible and unmeasurable.
 
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  • #68
john-of-the-divine said:
i was just looking for explanations that don t evolve math
I don't have such answers. Scientific answers involve assumptions, math, and experiments.
 
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  • #69
Orodruin said:
To be quite blunt, trying to accurately explain physics without math is like trying to explain the color green to a blind person.
wow...just wow.
 
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  • #70
john-of-the-divine said:
I just wanted to know how do you know %100 that the light from billions of light years away, when in fact, it's nothing more than a best guess? even though I'm no math expert, it really isn't that far fetched to believe the math could have been forced to fit a model. just because the math works doesn't make it anything less then a best guess. but, like I said, we won't know for sure till we go out there and look.

You seem to be taking a philosophical position regarding "proof "
It is far fetched to think that the math was "forced" to fit a "model"...particularly when the "model" is described by math lol

"Forcing to fit" the model is when we use words to describe the model, instead of math. Such as forcing the word "fabric" into the concept of spacetime geometry.

I explored square root once so I could understand it better. Like in all of physics math, the concept of square root has basis in the physical world.

Read about math, the concepts ect. Follow along reading the equations, look up what they mean...until you find an example of "forced to fit" and present it here; as of now I don't think "forced to fit" is well defined if at all.
 
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  • #71
john-of-the-divine said:
I'm not necessarily anti math, and I'm not unwilling to learn it
I would recommend starting with special relativity. All it requires is high school level algebra and geometry. It will introduce the concept of spacetime and the idea of Minkowski geometry which is different from Euclidean geometry, but is still very concrete as far as being able to draw pictures. You can learn about the experiments performed to date and the alternative theories that have been ruled out. You can learn about reference frames and laws of physics and causality.

Wheeler's Spacetime Physics is highly recommended, and there are a lot of online free resources too.
 
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  • #72
john-of-the-divine said:
just because the math works doesn't make it anything less then a best guess

Math is logic applied quantitatively. You can't give up math without giving up the underlying logic. Don't you want your answers to be logical?
 
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  • #73
Vanadium 50 said:
Math is logic applied quantitatively. You can't give up math without giving up the underlying logic. Don't you want your answers to be logical?

exactly! You're good at stating things clearly.
 
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  • #74
thank you, all of you. I know th8s is a debate I should have had with my professor, but I never got that chance. I appreciate the patience and non-buttheadness. I am, i feel, an ameture philosopher, at least some one noticed, lol. I do want to understand because because science is a big part of my belief system/philosophy. I'm just looking for undeniable truth is all. thank you, guess I have to learn the math. ouch, lol
 
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  • #75
I am not entirely confident in my knowladge to make replies in this forum, however, looking back to my younger age i would apprectiate someone saying this to me, so i will write it.
john-of-the-divine said:
even though I'm no math expert, it really isn't that far fetched to believe the math could have been forced to fit a model. just because the math works doesn't make it anything less then a best guess. but, like I said, we won't know for sure till we go out there and look.

Physics without math doesn't really work.

One simple example - you know Newtonian theory of gravitation from high school i guess? Then you remember - two objects of certain mass attract each other and the closer they are, the more they attract each other (and as 1/r2 which means the force goes to infinity when distance goes to zero). Someday you may come across a situation where two wet plates of glass touch each other, and glue themself together. And you remember - they have some mass, so they attract each other. Since they touched, they are very very close together, so the attraction is very strong and that explains why they seem to be glued to each other. Sounds logical. But what if they weren't wet? Then the attraction is weak. But if they are touching each other the attraction should be strong. Then you say - ok, perhaps the plate is not perfectly polished, so it is not touching each other perfectly. And since water is fluid, it will fill the empty spaces and touching will become again perfect.

And on and on you can go explaining stuff using ideas you read somewhere in pop-science books, but you will never know wheter what you said is the actual "truth" or some random mix. You need to make actual calculations to see wheter it fits what you observe or not.

Then there is problem with clarity. When you say something, you need to know what it means. What is space-time? What is electron? What is gravity? What is electromagnetism? You need math to give those words meaning that cannot be misunderstood. And when you go into more and more modern stuff, the misunderstanding will happen with bigger and bigger certainty, because language we use in our everyday lives, and experiences we have are simply too different from what is going on in the math.

When i was at high school i enjoyed so much reading pop-books like hawkings books etc., but looking back (i am doing masters degree now) i didnt learn from those books and discussions on the internet anything at all. It is only now that i can read those books and understand what they mean.

john-of-the-divine said:
I know there has to be something that mass effects to create gravity. I used the term "fabric" as a reflection of that something knowing it's really not a fabric, hahaha. But, this field, do you think it's the "aether", just different then what was once thought to exist?

Physics doesn't care about question "what is this". It cares only about properties. We say - the thing i am talking about (spacetime) has such and such influence on this and this thing. Then we look around and see wheter those influences are observed. If yes, then we say we have good theory and we are happy. But we don't ponder about what it is. And reason is simple - because it is unknowable. All information that comes to you is only of appearances and properties. It is similar to question - do we both see the same picture in the same way? If you see red as i see green, but you call it red, because you were taught to, then you would see different picture in your mind, then the one i see. And there is no way to convey the information of what you see to me, since when it comes to me, it is my brain who interprets it and creates mental picture. So one should forget about this philosophical questions and start looking only on appearances, properties = math. The non-mathematical explanations are only to help intuition to be able to better work with math (or to catch interest of your audience), but it is not fundamental part of science.

We have model of spacetime called general relativity. With this model we can simulate things we observe in universe and ask wheter the simulations have same results as what was observed. If they are same, we are happy and confident with our model until some disagreement is found. If spacetime would slow down photons, then certianly observing distant galaxies we would found disagreements with our model. I am no cosmologist, but i know there are some problems with our models and some people work on new theory of gravity that would explain it better (and there is of course problem of quantum gravity). This discussion i leave for actual experts, but my point was this: we only concern ourself wheter the theory works or not. You said you cannot bend nothing, so be it. Call it different name than nothing, imagine whatever you like. But it has to have the same properties as our purely geometrical approach (assuming our theory works) in order to explain observed phehomena. But in the end it doesn't matter. What matters are only properties, because only those are knowable, other than that is only imagination and speculations. Good for intuition or wonder - but are not fundamental part of science.
 
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  • #76
Umaxo said:
Since they touched, they are very very close together, so the attraction is very strong and that explains why they seem to be glued to each other. Sounds logical.
Please do not attack your own straw men. The centers of mass of the plates are not touching. More relevantly, if you do the integration, the force does not get huge just because the surfaces are touching. The failure is not because the math is wrong. It is because one did the math wrongly.
 
  • #77
jbriggs444 said:
Please do not attack your own straw men. The centers of mass of the plates are not touching. More relevantly, if you do the integration, the force does not get huge just because the surfaces are touching. The failure is not because the math is wrong. It is because one did the math wrongly.

Exactly
 
  • #78
john-of-the-divine said:
thank you, all of you. I know th8s is a debate I should have had with my professor, but I never got that chance. I appreciate the patience and non-buttheadness. I am, i feel, an ameture philosopher, at least some one noticed, lol. I do want to understand because because science is a big part of my belief system/philosophy. I'm just looking for undeniable truth is all. thank you, guess I have to learn the math. ouch, lol
May I suggest Relativity for Poets by Ben Crowell (a former member of staff on this forum), which you can download for free from http://lightandmatter.com/poets/.

It's mostly text and diagrams with very little maths.
 
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  • #79
john-of-the-divine said:
I'm just looking for undeniable truth is all. lol

René Descartes did the same and is a neat story.
 
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  • #80
john-of-the-divine said:
I'm saying that compared to the size of the universe, the distance to the moon is like an inch compared to 100 miles. I don't know the actual scale...

The diameter of your estimate for the size of the Universe is less than 2.6 light years.
Archimedes in The Sand Reckoner about 2250 years ago figured about 2 light years.
 
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  • #81
jbriggs444 said:
Please do not attack your own straw men. The centers of mass of the plates are not touching. More relevantly, if you do the integration, the force does not get huge just because the surfaces are touching. The failure is not because the math is wrong. It is because one did the math wrongly.
hey, he said he might not have enough knowledge
DrGreg said:
May I suggest Relativity for Poets by Ben Crowell (a former member of staff on this forum), which you can download for free from http://lightandmatter.com/poets/.

It's mostly text and diagrams with very little maths.
thankyou, I appreciate it a lot.
 
  • #82
bahamagreen said:
The diameter of your estimate for the size of the Universe is less than 2.6 light years.
Archimedes in The Sand Reckoner about 2250 years ago figured about 2 light years.
see, that's what I'm saying, is the math "calibrated" big enough? guess that's a better question. light is a photon, right? and everything else of the known energy spectrum, are those made of photons?
 
  • #83
john-of-the-divine said:
see, that's what I'm saying, is the math "calibrated" big enough?
We use the observations to calibrate the model.
 
  • #84
Dale said:
We use the observations to calibrate the model.
and we can only observe what we can see
 
  • #85
john-of-the-divine said:
and we can only observe what we can see
No
 
  • #86
Dale said:
No
ok, then we can only observe what we can observe. by you saying no is saying every thing in exictance is observable to us now. that heresy against science
 
  • #87
john-of-the-divine said:
then we can only observe what we can observe.
Yes, tautologically
 
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  • #88
Dale said:
Yes, tautologically
exactly
 
  • #89
what if the Michelson Morley experiment failed because the spliter and mirrors each technically became a new "source" of light.
 
  • #90
john-of-the-divine said:
what if the Michelson Morley experiment failed because the spliter and mirrors each technically became a new "source" of light.
The explanation for the null result (not a failure) is already consistent with considering the mirrors and beam-splitter as sources. This is an application of Huygens' Principle.
 
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