General Relativity question/problem
Discussion
Toltec said:
Niffty951 said:
I would love to do a physics degree to form a learned opinion but as I'm too old and busy earning bread to support society to take another 3 years of my life out I'm trying to learn it from books and questions.
In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Relativity is not easy to grasp intuitively based on human experiences of reality, as a, very, loose analogy is like the concept that the shortest route between two points is a straight line, however if you live on the surface of a sphere it is in fact a great circle line.In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Edited by Niffty951 on Wednesday 12th September 07:07
From above it may look like a straight line.
annodomini2 said:
Toltec said:
Niffty951 said:
I would love to do a physics degree to form a learned opinion but as I'm too old and busy earning bread to support society to take another 3 years of my life out I'm trying to learn it from books and questions.
In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Relativity is not easy to grasp intuitively based on human experiences of reality, as a, very, loose analogy is like the concept that the shortest route between two points is a straight line, however if you live on the surface of a sphere it is in fact a great circle line.In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Edited by Niffty951 on Wednesday 12th September 07:07
From above it may look like a straight line.
Morpheus, I'm beginning to believe.
I understand there is significant evidence for the existance of such distortion beyond the realms of our perception. Gravitational waves for one, although that doesn't help me picture the fabric of space time in 3 dimensions sadly.
What was the light bulb moment for you?
I understand there is significant evidence for the existance of such distortion beyond the realms of our perception. Gravitational waves for one, although that doesn't help me picture the fabric of space time in 3 dimensions sadly.
What was the light bulb moment for you?
Niffty951 said:
I would love to do a physics degree to form a learned opinion but as I'm too old and busy earning bread to support society to take another 3 years of my life out I'm trying to learn it from books and questions.
In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Do you understand using matrices to describe a rotation? If you take any X and Y on a plane then you can apply a rotation matrix that transforms it into X’ and Y’ which is the same as rotating that point around the origin. Some things are retained under rotation (separations, for example) and some things are not, such as direction and projection onto the X axis.In answer to the above I could break a convoluted route down into vectors and logically prove the two locations. What I can't seem to do with general or special relativity is easily break down the end result into logical steps to see the workings.
Edited by Niffty951 on Wednesday 12th September 07:07
Special relativity is nothing more than rotations in more dimensions. We describe it as 3+1rather than four, as one of the dimensions, time, has an i in front of it, as in the square root of -1.
If you can learn to view it in this way, it’s all pretty simple.
A lot of people fall over by trying to ask what’s “really” happening. They accept the results but assume that there is still one “right”frame, one “true” time and so on, which there just is not.
Niffty951 said:
Morpheus, I'm beginning to believe.
I understand there is significant evidence for the existance of such distortion beyond the realms of our perception. Gravitational waves for one, although that doesn't help me picture the fabric of space time in 3 dimensions sadly.
What was the light bulb moment for you?
You are mixing up general and special relativity again. It’s probably helpful if you concentrate on one at a time. Special relativity is a subset of General, but the maths in General is a lot harder for most people to follow, and is far less intuitive.I understand there is significant evidence for the existance of such distortion beyond the realms of our perception. Gravitational waves for one, although that doesn't help me picture the fabric of space time in 3 dimensions sadly.
What was the light bulb moment for you?
Niffty951 said:
I would love to do a physics degree to form a learned opinion but as I'm too old and busy earning bread to support society to take another 3 years of my life out I'm trying to learn it from books and questions.
Well, get a good physics degree and you could maybe support society even more if it leads to a better job. The OU does physics degrees, and my degrees in the subj ct helped me get into the current career.Are you trying to read the right sort of books, undergraduate physics texts? These are better than popular science books. The Feynman lectures is a decent set.
If you want to ask questions that will help with your understanding then I’d suggest leaving general relativity for now, and sticking with special.
It’s hard to see, from this end of things, what it is that people get themselves in knots about. To return to the 2D analogy, time dilation is no different to saying that if one person heads North and one head cat sixty degrees to North then each will see the other as falling behind. If one does two sides of a triangle then they will have to travel further than the one who does one side. This is analogous to the twins “paradox” which is not a paradox at all.
Thank you for those last responses. I've been thinking on the matrices comment, that is something I can picture in 3 dimensions. Useful to solve the problem mathematically. The 2D example equally.
Feynman is also my favourite lecturer, I love his passion, depth of knowledge and lack of ego. It's all about the beauty of nature for him.
Speaking of which, I think this is where I get tied up. Any other problem can be tackled by logic, mathematics and imagery. They usually compliment each other.
Even the invisible nature of magnetics and the nature of atoms can be pictured on a macro scale and the maths involved can be linked back to those images. It completes the picture.
With relativity I can picture the vectors you mention but I can't relate it to any other physical representation.
Could it be related to refraction of light through different densities? Not that this provides a great leap in my understanding as I don't understand what happens to the extra energy of the light when it loses ..velocity? No? Frequency? How does the constancy of the speed of light hold here? Different frequencies take different paths but they all cover the same distance in the same time? What happens to the lowest frequency? If frequency is an energy level what happens when it drop to zero and what happens to the energy it loses? Mass? (I'm losing all knowledge here, I'm sure much of this is simpler than I'm currently muddling)
Getting very tangental now but I wonder if by using your vector analogy and having sufficient mass in a black hole you'd get a 'change in angle' such that light does not propogate in xyz but instead moved in...time? (what is the dimension I'm missing here for a 4th dimension?
Sorry, I'll go in search of more Feynman lectures until I understand. I find it hard to jump in and out of his lectures (and without worked examples) as you do with youtube.
Feynman is also my favourite lecturer, I love his passion, depth of knowledge and lack of ego. It's all about the beauty of nature for him.
Speaking of which, I think this is where I get tied up. Any other problem can be tackled by logic, mathematics and imagery. They usually compliment each other.
Even the invisible nature of magnetics and the nature of atoms can be pictured on a macro scale and the maths involved can be linked back to those images. It completes the picture.
With relativity I can picture the vectors you mention but I can't relate it to any other physical representation.
Could it be related to refraction of light through different densities? Not that this provides a great leap in my understanding as I don't understand what happens to the extra energy of the light when it loses ..velocity? No? Frequency? How does the constancy of the speed of light hold here? Different frequencies take different paths but they all cover the same distance in the same time? What happens to the lowest frequency? If frequency is an energy level what happens when it drop to zero and what happens to the energy it loses? Mass? (I'm losing all knowledge here, I'm sure much of this is simpler than I'm currently muddling)
Getting very tangental now but I wonder if by using your vector analogy and having sufficient mass in a black hole you'd get a 'change in angle' such that light does not propogate in xyz but instead moved in...time? (what is the dimension I'm missing here for a 4th dimension?
Sorry, I'll go in search of more Feynman lectures until I understand. I find it hard to jump in and out of his lectures (and without worked examples) as you do with youtube.
Edited by Niffty951 on Wednesday 26th September 22:05
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