Lots of questions since college

[davidjoe]

How did you find PF?

Searched online general physics forums

Just joined. Not a physicist. Attorney since 1997 but repressed natural sciences mind.

That “textbook” ad above may not be a good sign, kiddos(?). Eventually one’s brother, no matter how smart, like my old physics teachers, finds no more entries in the “index”, and we passed pat answers long ago, so, I’m looking forward to wider audience.

Not just questions, but possibly some constructive armchair input thrown in too by me here or there. Glad to be onboard.

 

[DeBangis21]

Welcome to PF

 

[davidjoe]

Thank you DeBangis21

 

[davidjoe]

Although I purchased a copy of Relativity on 6/1/24, I didn’t start reading it in earnest until last evening.

In the first handful of chapters, notating in the margin as I read, my biggest question or open thought so far would be on the deference that is forming to the absolute speed of light C, its constancy in a vacuum, its unchanging speed as observed in all reference frames, and what becomes the premise that information cannot be translated or transmitted at a faster rate than C.

AE alludes early to presumably coming discussion on color shift and the Doppler effect, referring to a pitch change in sound.

Sound as well propagates at a certain speed through the air, and its perceived wavelength can be altered by an observer’s own motion, although the observer does not change the speed of sound.

However, that is not to say an observer cannot “preview” the coming information. If I live 1 mile from a high school stadium such that I can hear the game being announced a mile away, roughly 5 seconds of announcement information is traveling to me at all times.

I could shorten the 5 second delay in my receiving that information by driving a convertible toward the stadium, listening as I drove. Sound didn’t travel any faster, the pitch would change, but not beyond recognition. Traveling away from the stadium, I could extend the delay of hearing the bad news of a home team loss.

If we consider the earth and the sun, there exists roughly 8 minutes of the sun’s recent history in the form of information carried by light traveling toward us.

If we construe a particular 8 minutes of history as containing the appearance of a sunspot at minute 3 and the emergence of a solar flare at minute 8, and that is the only section or snippet of any concern to us, does the unchanged speed of light for all observers mean that a ship passing earth at time “0” and a uniform .2 C toward the sun, does not observe the sunspot sunspot appear or the solar flare, before earth receives that information?

When AE says of the two lightening strikes that there can be no simultaneity of relativity between the moving and stationary observers because of additive result of C plus the train’s speed, would that be suggesting that information can be transmitted or translated across a distance faster than C?

 

[berkeman]

The New Member Introduction forum is for brief intros only, not for questions. Please have a look at this PF Insights article:

https://www.physicsforums.com/insights/speed-light-frames-reference/

If you still have questions about the constant speed of light, you can start a new thread in the Relativity forum to post your references and ask your questions. You might do a search there first to read through the many other threads on the subject (in fact there are 1 or 2 current threads there now on the subject).