Re: Approximately 300,000 km/s With Respect To What?

Am Sonntag000014, 14.07.2024 um 12:19 schrieb Mikko:

On 2024-07-13 08:08:44 +0000, Thomas Heger said:
 

Am Freitag000012, 12.07.2024 um 11:26 schrieb Mikko:

On 2024-07-11 19:58:02 +0000, amirjf nin said:
>

Approximately 300,000 km/s with respect to what?

>
Whenever the speec of something is measured it is measured with respect
to someting else. The report should make clear what is the reference that
is considered stationary. Usually it is the instruments used in the
measurement, and usually but not always they are at rest with restpect to
Earth surface at the place of the measurement.
>

>
'Stationary' can be understood as 'not moving' and that as 'having
 velocity zero'.

 Yes, that is what the word means.
 

But velocity would require a reference point, in respect to which the object does not move.

 That gives you a revefernce point: the object does not move in respect to
itself.
 

Actually I have used this setting in my 'book' and declared, that all observers regard themselves as non-moving.
This is possible, if all inertial reference frames are of equal rights.
I can therefore use this setting, because it makes some sense and is allowed.
BUT: if the observer does not move, how could he possibly reach v=c???
So I turned the 'twin paradox' upside down and applied it to the point of origin (e.g. the Earth if a spacecraft starts from there).
...
TH