this post was submitted on 15 Jun 2024
872 points (99.4% liked)
Technology
59607 readers
3431 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
This is slighlty different though, we only know the two-way speed of light, not the one way speed of light.
We only know that this trip, to and back, takes x seconds. We cannot prove that the trip to the mirror takes the same length of time as the way back.
The special theory of relativity for example does not depend on the one way speed of light to be the same as the two way speed of light.
Wiki
With a detector and very accurate clocks, it would be easy to say "I'm going to send a pulse at 2pm, record when you receive it" that's measuring it in one direction
The very accurate clock needed in this case is physically impossible as far as we know, there's no way to measure it as far as our current understanding of physics goes.
Though if you can figure out a way you should publish a paper about it.
The clocks involved in gps are accurate enough that they have to take relatively into account for gps to be accurate. That's far more accurate than you need to measure the speed of light.
And to calculate the offset needed to get them all synced up involves calculating time dilation, which involves knowing/assuming the speed of light. These synchronizations work just as well if the two way speed of light is different than the one way speed of light.
To know the speed of light you assume the speed of light is c, but you're trying to calculate c so all those clocks aren't verified synced.
Just read through the wiki or Harvard's books if you'd like, this is an unsolved "problem" in physics for a reason or do you think no one cares about how fast c is?
See also This or, more accessibly "Synchronization conventions"
I read all those and every test has reduced the amount that the speed of light could be anisotropic. From "it could be twice as fast in this direction to the other" to "it could be a small fraction of the relativistic effect of moving a clock through space." Every improvement in measurement trends towards isotropic.