# What is the difference between SR and GR?

Discussion in 'General Science & Technology' started by Mark Turner, Jul 5, 2019.

Messages:
350
james

2. ### Google AdSenseGuest Advertisement

to hide all adverts.
3. ### James RJust this guy, you know?Staff Member

Messages:
39,421
What's this H thing?

I get that it's a distance of some kind. Light, travelling at 299 792 458 m/s would take 1.3333 seconds to travel distance H.

Light would take 1 second to travel that distance.

Is this a light clock?

Let's assume it is. Then let's make H =299792458 m the distance between two mirrors that are stationary (on a spaceship, say). Somebody watches that spaceship fly past at speed v, and the light follows a "slanted" path as it travels between the mirrors. Then d is the "slanted" path distance, which you call "angular path distance".

So, in the spaceship rest frame, the light takes 1 second to travel between the mirrors - call that one "tick" on the spaceship, or one "spaceship tick".
In the "outside" frame, the light takes 1.333 seconds to travel between the mirrors - call that one "Earth tick".
The fact that it takes different times in the two frames is due to the assumption that the speed of light is the same in both frames - a fundamental assumption of Einstein's special theory of relativity.

It follows that "outside" observers say that the spaceship clock is running "slow", because 1 spaceship tick equates to 1.333 Earth ticks.

With a bit more analysis, we can determine that the speed of this spaceship, relative to the Earth, must be 0.66 c, where c is the speed of light.

---
So, that's all fine. Now what?

4. ### Google AdSenseGuest Advertisement

to hide all adverts.
5. ### Janus58Valued Senior Member

Messages:
2,394
Okay, I am going to assume that you mean that H here is the distance between mirrors measured perpendicular to the relative motion between the pairs of mirrors. In other words, if the mirrors are moving horizontally, then H is the vertical distance ( or height) between the mirrors of any given pair. ( though you really should differentiate between the two "H"s. Such as H1 for one pair of mirrors and H2 for the other pair.

So if someone where at rest with respect to light clock 1 and with H1 being 399723277 m, and was comparing his light clock to light clock 2 with H2 being 299792458 m, and the two mirrors had a relative velocity of 0.639c, then the light clock 1 observer would note that light clock 2 would remain in sync with his own clock.

However, an observer at rest with respect to light clock 2, would note that light clock 1 runs much slower than his. While it takes 1 sec for light to travel the 299792458 m between his mirrors, the light for clock has to travel along the diagonal and has to deal with a larger vertical distance. Thus he will measure light clock 1 as taking nearly 1.7 sec to complete one tick. ( though I also should point out for a light clock one "tick" involves a complete round trip from one mirror to the other and back and not just one leg. This distinction becomes very important if you were to lay your light clock "on its side" so that the light bounces back and forth parallel to the relative motion between clocks, as now you have to contend with relativity of simultaneity. )

6. ### Google AdSenseGuest Advertisement

to hide all adverts.
7. ### Mark TurnerBannedBanned

Messages:
350
Not quite , in your spaceship frame the one tick is 1.33s , not 1.s . The observer now knows they were wrong with their first notion of 1.s because we've established the angular distance is greater than 299,792,458 m .

Let us return to the original thought experiment and equal our clocks heights .

The stationary clock registers 1.3 ticks while the clock in motion also measures 1.3 ticks based on c constant .

There never was a time dilation , only fake science and let's say the wool pulled over peoples eyes .

Anyway I've demonstrated Einstein incorrectness , I can quit science now .

Thank you for listening..

8. ### originHeading towards oblivionValued Senior Member

Messages:
11,890
First, thanks for quitting science, you won't be missed.
Second, you way over played your "questioning student" approach. You should have exposed your true motives 150 posts ago. Your threads were kind of fun and and many participants brought up some interesting points. So you accidentally added positively to the site.
Ironic.

9. ### James RJust this guy, you know?Staff Member

Messages:
39,421
No. You specified the distance between the mirrors in metres as 299792458 m. Light takes 1 second to travel that distance, not 1.33 seconds.

Note that I analysed the same situation for two different observers, above. Which one are you talking about?

Already done. That was the scenario I analysed above.

No. I showed above that the clock seeing the mirrors move measures 1.33 seconds for every 1 second measured by the clock that doesn't see the mirrors move.

No. You just made a bunch of mistakes, that's all.

No. You just made a bunch of mistakes, that's all. You can still quit science, though. You're not very good at it.

Last edited: Aug 3, 2019
10. ### Mark TurnerBannedBanned

Messages:
350
Apparently not , maybe I should find another pass time hobby instead .
According to me I know everything when in reality I know nothing.
I apologise for being an illiterate deluded fool who constantly posts stupid things , I can't count the times I've posted nonsense , that's being nutz for ya ....

Anyway , thanks for your reply .

11. ### James RJust this guy, you know?Staff Member

Messages:
39,421
Well, you've got to admit that claiming you've "demonstrated Einstein's incorrectness", while you're posting error after error, doesn't do much for your reputation as somebody who knows the science.

Maybe if you asked questions more and made grandiose claims less, that might work better for you. Just an idea.