Relativity and Cosmology

Jorrie,

Hi, it's been a while. I've read your rather interesting (and muddy) post. I guess the way I've come to think about it is that time and space are inextricably linked and any time we try to divide them into separate independent variables rather than the coupled variables that they are, we are doomed to fail (unless we are going slow and don't worry about precision).

I guess what I'm trying to say is that there isn't really any such thing as "space" and there really isn't any such thing as time. These are just relics of a time when we were struggling to describe the world we lived in and these two things seems separate. The truth is, there is only space-time.

So when we ask "which clock ticks slower" the flaw in the question is we've specified a time, but not the corresponding space aspect (where the observer is with respect to what is being observed).

Anyway, you've done much to shape my thinking on this subject, so if you disagree with what I've said or feel I'm making a mistake in my logic, please let me know where I'm going wrong.

Roger

Hi Roger, you are thinking right! Spacetime is the more "absolute concept", specifically the spacetime interval, which is invariant.

As far as time is concerned, there are some situations where we can detect a time difference due to movement and others where we can't!

Jorrie

Hi, Roger.

Try this on and see if it doesn't make a bit more sense, (Jorrie, keep an eye on this one. I'm sticking my neck out and I don't want to disseminate incorrect concepts.)

Two objects can occupy the same space at different times and they can occupy the same time in different places, but two objects can not occupy the same space-time. Unless there is some way to time it so the two objects interface perfectly.

That either made it better or worse, I can't tell.

/Ari (Orpheuse)

hi Ari, you wrote: "Two objects can occupy the same space at different times and they can occupy the same time in different places, but two objects can not occupy the same space-time."

Strictly speaking, you are right, but they can come close enough in spacetime for all practical purposes. I consider my computer and myself to be in such a position. In relativity, we usually consider objects that "pass each other" as if they practically go through each other...

Jorrie

You are going to send me back to Bertrand Russel, aren't you.

Thank you for the idea that "two objects passing each other closely enough is thought of as if the 2 objects practically go through each other . . ."

That changes a great many things in my reality matrix. I'm going to be up all night rewiring my pre-frontal lobes. Oh, well, I guess the cob-webs needed cleaning out anyway.

Thanks for the heads up.

/Ari

For me, the important thing is the phrase "in relative inertial motion". When seen in a different reference-frame what we see is going to be different. That includes Space-Time.

It was once thought that Electricity and Magnetism where 2 forces until some bright young man realized that you never have one without the other, therefore, electromagnetism is now viewed as one force. So it is with Space-Time. It is one homogeneous unit, forever linked and, as far as we know, elemental. Problem is, I'm not really thinking (outside the box, pun intended), I'm merely being logical.

We'll know more once they get the bugs out of the new Super-collier.

/Ari (Orpheuse)

Yeah, the Super-collier should have come with a flea collar

Hi, Steve,

If you can make a dog collar 7 miles in diameter, I can get you a page in the Guiness Book of World Records for sure.

Hi Ari, yes the spacetime forms a "homogeneous unit", as you said.

The issues about clocks do not really from part of the LHC expectations. The time dilation effects have been reasonably well established by the previous generation of particle accelerators, shooting lighter particles, like electrons and mesons.

Nevertheless, as you said, LHC will surely produce new insights into particle physics at high energies.

Jorrie

Between this and the U.S Presidential elections, this has proven itself to be a very exciting time to be alive.

Keep us posted, Jorrie

/Ari (Orpheuse)

Do moving clocks really 'tick slower'?

Is Your question is do mechanical clocks tick slower than the electric motor driven and slower than the atomic world clock do?

The answer is yes they do. However it is less than 10 seconds a year with most. Under a minute for a cheep wind up if kept wound up every day.

Time and space are and always have been 2 different subjects. Long have they been intermixed it telling stories and facts.

Time is a man made concept to tell where he is at!

Space is the absence of anything solid.

Time and space can exist one without the other.

You can place a time on a event.

You can not place where it happen in space.

It appears to me that we are trying to generlize or categorize two different media. You said "Time is a man made concept to tell where he is at!" There is the falacy. If I am correct in my assumption, "...where he is at!" indicates a physical location. Time is not a physical measurement. I define time as "A framework for events." It is a way of measuring the duration of a particular event. The measurement terms or units of measure is a comparison to the duration of other or another event. It is not an empirical measurement in that there is nothing that can be adequately defned by the term "time." It, again, is a comparison.

Now, as to whether the duration or frequency of the ticking of a time measuring device (clock) is more frequent or less than that of a another, moving clock, I would consider a mechanical time measuring ( or comparing, if my premise is going to be believed) device utilizing a pendulim to activate or count the units of measure assigned to "time" (minutes...years). The obvious difference that may occur in two measuring devices of this type, but offering up the same product, is the length and weight of the pendulum. The longer pendulum arm would "tick" at a slower pace, producing less "ticks" within a given duration of time and still announce the same dusation as one with a shorter arm producing more "ticks" within the same time duration, the fact notwithstanding that one or both of the devices may be moving while the count is being taken.

I don't know. Just seems to be to much expansive thinking for me. Just some food for thought.

I have two questions.

1. How fast would you need to travel to slow your clock ticks by half?

2. I was wondering if our timerate is determined by our speed through the cosmos, the gravity of Earth, the Sun, etc. all summed up equals one second per second.

Hi guest. Your questions:

1. "How fast would you need to travel to slow your clock ticks by half?"

That relative speed is 0.8666c. Note that in purely inertial systems, that "slowdown of tick rate" is apparent, because either observer views the others clock to tick at half his/her own clock's rate...

2. "I was wondering if our timerate is determined by our speed through the cosmos, the gravity of Earth, the Sun, etc. all summed up equals one second per second."

Time runs at one second per second for everyone, irrespective of where they are or at what speed they move. That's the way time is defined - it's private, belonging to the observer! It is only when two observers under different conditions compare rates that a difference becomes apparent.

Jorrie

Jorrie,

I'm pretty sure the answer is yes but I just want to make sure. If we travelled close enough to the speed of light (I'm talking really close .999......c), then we could travel clear across the visible universe in what to us (on the ship) would seem a second or less, however many billions of years would have passed on Earth, due to the time dilation on our ship with respect to observers on Earth?

I know the above is impossible because of energy considerations. In quantum mechanics energy and time are conjugate variables related by:

,

Here is an interesting read for you Jorrie:

http://en.wikipedia.org/wiki/Uncertainty_principle

Just skip to the part at the bottom about the Energy-Time Uncertainty Principal. They talk of how early in quantum mechanics the principal was anticipated because of the existing relation between time and energy in relativity.

Roger