Why Doesn't The Speed Of Light Change?

[David Jerome]

Why is it that the speed of light is constant, and not even affected by gravity?

 

Also...logic dictates that if you shoot a gun from a moving car, the bullet moves at it's normal speed, plus the speed of the car. However, I've heard this isn't true for light; that the speed of light is 186,000 miles per second. Is that true? If so, why is that?

 

If this is too difficult to explain in a post, I apologize. I'll read whatever links you can post, if that's the case.

[CraigD]

Welcome to hypography, David! :)

 

Also...logic dictates that if you shoot a gun from a moving car, the bullet moves at it's normal speed, plus the speed of the car. However, I've heard this isn't true for light; that the speed of light is 186,000 miles per second. Is that true? If so, why is that?

A short answer is “because light propagates like a wave."

 

Think of wave on the surface of a body of water. If you drop a stone from a pier, the speed of the waves it produces doesn’t depend on if your stationary, or how fast you’re walking, on the pier. So – sort of – is it with light.

 

It gets more complicated, however, because not only does the speed of light not depend on the speed of its source, it’s also not constant relative to some medium, like the water in a water wave. Continuing the example above, it’s as if, when you try to figure out which way the water under the pier is flowing by watching waves on it, it appears stationary to someone sitting still on the pier, but also appears to be flowing at a rate and direction exactly matching someone walking along the pier. This isn’t possible for water waves, but, weirdly, is for light.

 

The surprisingly weird behavior of light wasn’t anticipated by science ‘til the late 1800s. Though the weirdness was pretty convincingly shown with experiments by 1887, most famously the Michaelson-Morley experiment, it wasn’t well-described ‘til Einstein did it in 1905, becoming arguably the most famous scientist to date in the process.

 

The behavior of light – of all kinds, visible and invisible – is so strange and counter to our experience with everyday objects like baseballs and bullets, that to this day, some folk on the science fringe simply refuse to believe it. You’ll encounter lots of these folk on the internet, including here at hypography, though not so much so, as we have a rule about not making unsupported claims, which tends to voluntarily and involuntarily drive them off.

 

There are lots of good histories and popular science articles on this, which include more on the little bits I threw in above. Wikipedia’s “history of special relativity” is one.

[CraigD]

Current theories avoid any direct answer, I gave you a direct answer but it is not yet mainstream and there is much resistance.

...

It is the hidden mechanism of how it is possible that I explained in my previous post, which was transferred to the strange answer category.

...

Storyteller’s previous posts, and replies to it, were moved to the Strange Claims forum thread Strange replies to “Why Doesn't The Speed Of Light Change?” More such posts should be made there.

 

Hypography’s site rules, which, when we joined, we agreed to read and follow, include an important ground rule: in general, back up your claims by using links or references. Posts that fail to follow this rule may be moved to the strange claims forum.

 

The main purposes of this rule is to encourage members to research their claims before posting them, and to allow readers to follow these links to better understand the posts. In my experience, the vast majority of claims that “mainstream” theories fail to give understandable answers to common questions are due to a failure to study these theories well enough. Likewise, most “new alternatives theories” show a lack of appreciation of research into discarded old theories that were discarded in the course of the development and acceptance of mainstream theories. In short, before rejecting the most popular current theories, I believe it’s important to understand them at least well enough to recognize old objections to them.

 

I think claims like Storyteller’s – essentially, that explanations that avoid the counterintuitive strangeness of special relativity can explain phenomena like the Michaelson-Morley experiment – are examples of what I meant here

The behavior of light – of all kinds, visible and invisible – is so strange and counter to our experience with everyday objects like baseballs and bullets, that to this day, some folk on the science fringe simply refuse to believe it. You’ll encounter lots of these folk on the internet, including here at hypography, though not so much so, as we have a rule about not making unsupported claims, which tends to voluntarily and involuntarily drive them off.

of refusing to accept the deep strangeness of the theory of relativity.

 

Reluctance to accept strange ideas is a healthy, skeptical tendency, and discussions of it worthwhile and well-aligned with the goals of hypography. Storyteller, if you're interested in such a discussion, continue it in Strange replies to “Why Doesn't The Speed Of Light Change?”, but making the extra effort to back up you claims with links or references of some kind. I hope this can lead to everyone having a deeper understanding of both physics and each other.