# Thread: about Bob's article on absolute or relative time

1. Originally Posted by Lighthouse
50 MPH is 50 MPH.
Is the kid at the edge of the merry-go-round going faster than the kid in the middle?

2. If I walk around the Earth at the equator does my head travel farther than my feet?

3. Originally Posted by fool
Is the kid at the edge of the merry-go-round going faster than the kid in the middle?
The kid at the edge of the merry-go-round is traveling further than the kid in the middle and must go faster to stay in the same spot as the kid in the middle. Just like on a racetrack.

4. Originally Posted by Lighthouse
The kid at the edge of the merry-go-round is traveling further than the kid in the middle and must go faster to stay in the same spot as the kid in the middle. Just like on a racetrack.
So the guy at the top of the mountain IS going faster than the guy at the bottom?

5. Originally Posted by fool
So the guy at the top of the mountain IS going faster than the guy at the bottom?
If they are standing still, yes.

6. Originally Posted by Lighthouse
If they are standing still, yes.
What if they're on treadmills?

No really So the guy at the top and the guy at the bottom have stared at each other thru telescopes across a distance that didn't change but they traveled differnt distances, just like in a race a guy who was on the outside comes to the finish line and and a guy who was next to him on the inside the whole time have different milages on their odometers for that race and then they shake hands?
Yes?
No?

7. Originally Posted by fool
What if they're on treadmills?

No really So the guy at the top and the guy at the bottom have stared at each other thru telescopes across a distance that didn't change but they traveled differnt distances, just like in a race a guy who was on the outside comes to the finish line and and a guy who was next to him on the inside the whole time have different milages on their odometers for that race and then they shake hands?
Yes?
No?
I didn't understand what you meant at first.

But the bottom line is that the top of a mountain travels faster through space than the core of the Earth, in the Earth's rotation. Because the top of the mountain must travel further, and yet must keep up.

None of this changes the rate at which time passes.

8. Originally Posted by ThePhy
Don’t understand orbital mechanics very well, do you? Watch an astronaut working outside on a many-ton space station in orbit. When he gently lets a one-ounce tool loose it floats right along in the same orbit as the monstrous structure that it is now totally disconnected from.
I'm not sure your example is equivalent to changing the moon into an apple.

I will admit that I really thought you understood the difference between the effects of gravity on the two dissimilar types of clocks. But alas, just like Huck Finn’s dad, I suspect the only thing that might keep you from regressing at the first opportunity (or getting dead drunk in the case of Huck’s dad) is a shotgun. The compensation is via relativistic equations, which include distortions in the flow of time.
Why is this assumption necessary. We have two clocks that respond differently according to the gravitational forces acting upon them. Why do we need time distortions to explain the differences? Why not just say that gravity affected the clocks?

9. Originally Posted by Lighthouse

Originally Posted by Stripe
I'm not sure your example is equivalent to changing the moon into an apple.
http://www.theologyonline.com/forums...3&postcount=58

10. My understanding of the physics involved is not as trained as the others, but my impression is that the Earth-Moon system is a dynamic one. That is the Moon is falling toward the Earth and the Earth is also falling toward the Moon. If the Moon were to turn into an apple and retain its velocity then the equations you posted would all skew toward the Earth. Thus the Earth would not fall toward the moon any more and the Moon's orbit would not remain as it is.

That sounds a fairly reasonable assumption to me, but I don't have the equations to back it up.

11. Originally Posted by Stripe
My understanding of the physics involved is not as trained as the others, but my impression is that the Earth-Moon system is a dynamic one. That is the Moon is falling toward the Earth and the Earth is also falling toward the Moon. If the Moon were to turn into an apple and retain its velocity then the equations you posted would all skew toward the Earth. Thus the Earth would not fall toward the moon any more and the Moon's orbit would not remain as it is. …
Technically you are correct. Though we casually speak of the moon orbiting the earth, in fact both the moon and the earth orbit around their common center of mass. With the moon being a significant sized body, that common center of mass is not at the center of the earth, but some distance towards the moon on the line from the earth’s center to the lunar center.

But replacing the moon with an apple would just mean the common center of mass of the “earth-apple” system would be a billionth of an inch displaced from the earth’s center, instead of kilometers as it is now. In common parlance (and in scientific literature) the apple would still be orbiting the earth, and at the same distance and speed as the original moon did.

12. Originally Posted by dan1el
It was so ignorant it didn't deserve an answer.

13. Originally Posted by Lighthouse
It was so ignorant it didn't deserve an answer.
That's quite ironic coming from you.

14. Originally Posted by Lighthouse
I didn't understand what you meant at first.
That's OK we'll get there.

But the bottom line is that the top of a mountain travels faster through space than the core of the Earth, in the Earth's rotation. Because the top of the mountain must travel further, and yet must keep up.
Good, so the guy at the top of the mountain is goig faster than the guy at the bottom. His miles traveled per day is greater than the guy at the bottom and his miles per hour are greater right?
None of this changes the rate at which time passes.
We haven't got to that yet.

15. Originally Posted by fool
That's OK we'll get there.

Good, so the guy at the top of the mountain is goig faster than the guy at the bottom. His miles traveled per day is greater than the guy at the bottom and his miles per hour are greater right?
He is going faster, yes. And his miles traveled are greater. What of it?

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