14 questions linked to/from Has the speed of light changed over time?
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### Space expanding, or light slowing down? [duplicate]

This question seems a lot like one of those "Phylosoraptor" memes all over the Internet, and it might be very silly, but I've been thinking about this for a while. Is it possible that space is not ...
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### Speed of light in vacuum - is it really a constant and what is the accurate value? [duplicate]

Let's suppose that the speed of light would not be a constant but a function of something. As is quite clear now, universe is expanding exponentially. If the speed of light would actually be a ...
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### Rebuttals for variable speed of light? [duplicate]

I'm finding a lot of popular articles about the "exciting" possibility that the speed of light might be changing. However, I'm having no luck finding a good rebuttal. My general understanding is that ...
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### Is it possible that the speed of light has changed since the beginning of the universe? [duplicate]

Asking purely out of curiosity: Is there any research or publication in Modern Physics that considers the possibility that the speed of light has changed since the Big Bang, and not remained constant ...
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### 2002 research: speed of light slowing down?

Back in 2002 there was some research published hinting that $c$ may have been faster at some distant point. It was based on measurements of the fine-structure constant,  \alpha = \frac1{4\pi\...
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### Why do universal constants have the values they do?

This is meant to be a generic question of the type that we get repeatedly on this site, in different versions: The origin of the value of speed of light The gravitational constant G theoretically? ...
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### The famous drop of $c$

In this (in my opinion) intriguing speech, Rupert Sheldrake tells the story of the drop in the measured value of $c$ between 1928 and 1945. When he goes to visit the Head of Metrology of the Physics ...
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### How can I explain the scientific basis of the constant speed of light to a $c$-decay proponent?

This Phys.SE question asks why and how the speed of light is constant. I would like to ask a related, almost converse question: Given that the speed of light is constant, how could I explain to a ...
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### Can the cosmological constant change with time?

This post is a specialization of the post: Can the proportion of dark energy change? Can the cosmological constant change with time? If so, is there a measurement of this evolution up to now, and ...
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### Does Universe really expand? What if the speed of light is decreasing instead?

What I am understanding on the articles I have read is that the conclusion "universe expands" depends on the assumption "the speed of light is constant". Of course it's not the major factor but what ...
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### What tells us the speed of light is constant in another galaxy?

I've read, and I hope to keep reading, so please send me all your links, and I apologize in advance if this is a duplicate, or non-mainstream physics question as the speed of light is widely accepted ...
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### Red Shift and Light Speed

I read several questions/answers about red shift on this web site, but there is something I still don't understand. Why is red-shift considered to be the effect of expanding space-time, why it could ...