"Spaceman" wrote in message
. ..

"OG" wrote in message
...
| OK, So if we have two events one here on earth and one on the moon, say
a
| laser being switched on at each place.
|
| What would 'simultanous' mean in this case?
| Would it be if the observer on earth saw the light go on on the moon at
the
| same time as he turned his own light on?
| Or would it be if the observer on earth saw the light go on on the moon
1.2
| seconds after he had switched his on?

If we are just talking about the distance difference
(no orbit or Earth spin involved),
The second choice would be correct technically.

OK, so let's imagine (B) travelling towards the moon at 0.5c - (B) sees the
earth-lab flash as he passes, but sees the moon-lab flash after just 0.6 s
later. Agreed?

"Greg Neill" wrote in message
. ..
| For material particles, yes, if you're referring to
| the observed deBroglie wavelength. For light,
| the observation velocity is fixed and the momentum
| change shows up as a frequency change.

What was changed about the momentum Greg?

"OG" wrote in message
...
| OK, so let's imagine (B) travelling towards the moon at 0.5c - (B) sees
the
| earth-lab flash as he passes, but sees the moon-lab flash after just 0.6 s
| later. Agreed?

Yup
Ok.

"Spaceman" wrote in message ...

"Greg Neill" wrote in message
. ..
| For material particles, yes, if you're referring to
| the observed deBroglie wavelength. For light,
| the observation velocity is fixed and the momentum
| change shows up as a frequency change.

What was changed about the momentum Greg?

That's like asking what was changed about the
size of something. The measured energy is
changed. Remember? You said yourself, photons
are packets of energy.

"Spaceman" wrote in message
...

"OG" wrote in message
...
| OK, so let's imagine (B) travelling towards the moon at 0.5c - (B) sees
the
| earth-lab flash as he passes, but sees the moon-lab flash after just 0.6
s
| later. Agreed?

Yup
Ok.

So simultaneous depends on how you are moving.

Now then.
When you are measuring the length of something you have to make sure that
your reference length is simultanously at both ends of whatever is being
measured. Agreed?

"OG" wrote in message
...
|
| "Spaceman" wrote in message
| ...
|
| "OG" wrote in message
| ...
| | OK, so let's imagine (B) travelling towards the moon at 0.5c - (B)
sees
| the
| | earth-lab flash as he passes, but sees the moon-lab flash after just
0.6
| s
| | later. Agreed?
|
| Yup
| Ok.
|
| So simultaneous depends on how you are moving.

No,
only "observation of the simultaneity" depends on how you are moving.
It does not change the simultaneity itself.
It merely gives a different observational illusion of
what is happening first or not.
The simultaneity does not change itself at all.


| Now then.
| When you are measuring the length of something you have to make sure that
| your reference length is simultanously at both ends of whatever is being
| measured. Agreed?

Yup,
OK
(but you have problems before this with your thoughts on simultaneity.)

"Greg Neill" wrote in message
. ..
| "Spaceman" wrote in message
...
|
| "Greg Neill" wrote in message
| . ..
| | For material particles, yes, if you're referring to
| | the observed deBroglie wavelength. For light,
| | the observation velocity is fixed and the momentum
| | change shows up as a frequency change.
|
| What was changed about the momentum Greg?
|
| That's like asking what was changed about the
| size of something. The measured energy is
| changed. Remember? You said yourself, photons
| are packets of energy.

The energy can not change without a speed difference
Greg.
How did the energy change without a speed difference Greg?

"Spaceman" wrote in message ...

"Greg Neill" wrote in message
. ..
| "Spaceman" wrote in message
...
|
| "Greg Neill" wrote in message
| . ..
| | For material particles, yes, if you're referring to
| | the observed deBroglie wavelength. For light,
| | the observation velocity is fixed and the momentum
| | change shows up as a frequency change.
|
| What was changed about the momentum Greg?
|
| That's like asking what was changed about the
| size of something. The measured energy is
| changed. Remember? You said yourself, photons
| are packets of energy.

The energy can not change without a speed difference
Greg.

Sure it can, if the frequency has changed. E = h*f.

How did the energy change without a speed difference Greg?

By a change of frequency. E = h*f.

"Greg Neill" wrote in message
. ..
| "Spaceman" wrote in message
...
|
| "Greg Neill" wrote in message
| . ..
| | "Spaceman" wrote in message
| ...
| |
| | "Greg Neill" wrote in message
| | . ..
| | | For material particles, yes, if you're referring to
| | | the observed deBroglie wavelength. For light,
| | | the observation velocity is fixed and the momentum
| | | change shows up as a frequency change.
| |
| | What was changed about the momentum Greg?
| |
| | That's like asking what was changed about the
| | size of something. The measured energy is
| | changed. Remember? You said yourself, photons
| | are packets of energy.
|
| The energy can not change without a speed difference
| Greg.
|
| Sure it can, if the frequency has changed. E = h*f.

Greg,
the frequency can't change without a speed change.
you have to change the speed to get the energy and the frequency
to change at all.


| How did the energy change without a speed difference Greg?
|
| By a change of frequency. E = h*f.

Greg,
the frequency can't change without a speed change.
you have to change the speed to get the energy and the frequency
to change at all.

Spaceman wrote:
"OG" wrote in message
...
|
| "Spaceman" wrote in message
| ...
|
| "OG" wrote in message
| ...
| | OK, so let's imagine (B) travelling towards the moon at 0.5c - (B)
sees
| the
| | earth-lab flash as he passes, but sees the moon-lab flash after just
0.6
| s
| | later. Agreed?
|
| Yup
| Ok.
|
| So simultaneous depends on how you are moving.

No,
only "observation of the simultaneity" depends on how you are moving.
It does not change the simultaneity itself.
It merely gives a different observational illusion of
what is happening first or not.
The simultaneity does not change itself at all.


Andy at earth-lab had to flash 1.2 seconds before he saw moon-lab's
flash to produce simultaneity, but (B) only had to flash 0.6 seconds
before seing moon-lab's flash to produce simultaneity. But both flashes
were at the same places (earth-lab and moon-lab).

Agreed?



| Now then.
| When you are measuring the length of something you have to make sure that
| your reference length is simultanously at both ends of whatever is being
| measured. Agreed?

Yup,
OK
(but you have problems before this with your thoughts on simultaneity.)