I What Experiments Demonstrate Time Dilation?

[PeterDonis]

Less gravity means there's a mechanical difference.

Yes, but any "mechanical difference" would have to be based on a difference in g, since that's the "mechanical" aspect of gravity. So, for example, his mental model would predict that clocks on the geoid at the poles should run at a different rate from clocks on the geoid at the equator, because g is different. But in fact they run at the same rate.

 

[gmax137]

I wouldn't waste any more mental energy on this friend.

Check this quote from him:
"I'm actually very curious how practically everyone doesn't see the inescapable logic here!"
Then he adds:
"I suspect many universities are polluting students minds during the last couple of decades."

'Nuff said.

 

[narrator]

I wouldn't waste any more mental energy on this friend.

Easy to get caught up in it, hey. But you're right.

 

[gmax137]

Easy to get caught up in it, hey.

Understood!

 

[FactChecker]

I would love to have been in young Einstein's shoes just for that one moment when his new theory explained the precession period of Mercury. What a thrill.

Yes! The part that really fascinates me is how he must have reacted when he realized that GR explained the nature of gravity. I wonder if he expected that.

PS. On the other hand, Einstein accomplished so many profound things that it might not have been so amazing to him.

 

[PeterDonis]

how he must have reacted when he realized that GR explained the nature of gravity. I wonder if he expected that.

I'm not sure what you mean. Explaining gravity while being consistent with relativity was Einstein's primary goal in developing GR. He didn't have to "realize" that afterwards.

 

[PeterDonis]

I would love to have been in young Einstein's shoes just for that one moment when his new theory explained the precession period of Mercury. What a thrill.

He actually got that thrill twice--first when his initial version of the field equation (which turned out not to be quite correct) got the correct result, and second when he found the final (correct) version of the field equation and it still gave that result.

 

[narrator]

PS. On the other hand, Einstein accomplished so many profound things that it might not have been so amazing to him.

He actually got that thrill twice

I watched a video a while back. The presenter, Dr Harry Cliff, said that Einstein was so excited by his equation proving Mercury's orbit that it gave him heart palpitations.

 

[sophiecentaur]

What happened to the Mods when we need them? We have spent 38 posts discussing that which we are just not allowed to discuss. I was wondering whether to start off a flat Earth discussion and see if I could get as many posts going.
I'd be 'dilated' to hear some comments. (From a Joan Rivers joke.)

 

[Frabjous]

What happened to the Mods when we need them? We have spent 38 posts discussing that which we are just not allowed to discuss. I was wondering whether to start off a flat Earth discussion and see if I could get as many posts going.
I'd be 'dilated' to hear some comments. (From a Joan Rivers joke.)

A tangent plane is not a bad approximation for many applications

 

[narrator]

You have my apologies if I've transgressed. It's been helpful to expand my knowledge of the topic in a positive way. So at least that's something, hey. I suppose I could have done so without the backstory.

 

[sophiecentaur]

You have my apologies if I've transgressed. It's been helpful to expand my knowledge of the topic in a positive way. So at least that's something, hey. I suppose I could have done so without the backstory.

Hardly your fault if hordes of PF members want to contribute to a chat about your friend's nonsense.

 

[PeterDonis]

What happened to the Mods when we need them?

If you think a thread discussion violates the rules, report it.

 

[Nugatory]

You have my apologies if I've transgressed. It's been helpful to expand my knowledge of the topic in a positive way. So at least that's something, hey. I suppose I could have done so without the backstory.

If you had transgressed unacceptably you would know about it. :)

We usually do not host discussions of crackpottery, even to debunk it because there is more crackpottery in the world then there is debunking bandwidth; and we usually do not allow arguments by proxy ("refute my friend...") because they are seldom advanced in good faith.

So far this thread has managed to remain productive and passes one of the basic tests: If three years from now a google search were to lead someone to it, would that be a good thing? But as it approaches the point of diminishing returns we will close it.

 

[sophiecentaur]

If three years from now a google search were to lead someone to it, would that be a good thing?

Do these things mature (or the reverse) with age?

I didn't consider reporting. I was just commenting on how members seemed attracted to this sort of thread 'like moths around a flame'. Nothing wrong with the content of the thread (except the "friend's" views) but I was a bit disappointed at the lack of self regulation.

 

[Sagittarius A-Star]

He reckons it's the different gravity on GPS satellites, not time dilation. I said yes, it's the different gravity, causing time dilation but he's not having it.

In addition to what others said:

Relativistic Clock Correction

The rate of advance of two identical clocks, placed one in the satellite and the other on the terrestrial surface, will differ due to the difference of the gravitational potential (general relativity) and to the relative speed between them (special relativity).

Source:
https://gssc.esa.int/navipedia/index.php/Relativistic_Clock_Correction

 

[Nugatory]

We seem to have reached the point of diminishing returns here, so the thread is closed.

If necessary, new threads can be started to cover anything raised by the discussion in this thread.