- #1
Loudzoo
- 43
- 0
I've had a good search through the archives and haven't found an answer to this question. Many apologies if this is old ground. . .
Having read the threads on the Pioneer Anomaly a quick question to which I'm sure there is very simple answer (I just don't know what it is !):
When calculating the expected trajectory of a space probe (or other low mass object) as it flys away from the sun (or other high mass object) its velocity will determine to what extent relativistic phenomena begin to become significant vs Newtonian expectations.
Do the rocket scientists consider the frame of reference of the space probe, the sun, or a 3rd party observer (say, the rocket scientist on earth) when calculating the expected trajectory of the probe ?
In a simple relativistic model with two bodies (the sun and the probe) its impossible to say which body is moving away from the other.
From the space probe's frame of reference it could be stationary and the sun could be flying away. Relativistically that would increase the sun's mass, and increase its gravitational influence on the probe that could lead to an otherwise unexpected deceleration in the motion between the two bodies.
From the sun's frame of reference it is stationary, the probe increases in mass due to its velocity but this causes no unexpected deceleration in the probe's trajectory from the sun because that tiny increase in mass (at any velocity other than closely approaching to the speed of light) has no material impact on the shared gravitational attraction between the two bodies.
Which frame of reference is correct to use ? Does it impact what trajectory we measure as a 3rd party observer with a different frame of reference again?
Having read the threads on the Pioneer Anomaly a quick question to which I'm sure there is very simple answer (I just don't know what it is !):
When calculating the expected trajectory of a space probe (or other low mass object) as it flys away from the sun (or other high mass object) its velocity will determine to what extent relativistic phenomena begin to become significant vs Newtonian expectations.
Do the rocket scientists consider the frame of reference of the space probe, the sun, or a 3rd party observer (say, the rocket scientist on earth) when calculating the expected trajectory of the probe ?
In a simple relativistic model with two bodies (the sun and the probe) its impossible to say which body is moving away from the other.
From the space probe's frame of reference it could be stationary and the sun could be flying away. Relativistically that would increase the sun's mass, and increase its gravitational influence on the probe that could lead to an otherwise unexpected deceleration in the motion between the two bodies.
From the sun's frame of reference it is stationary, the probe increases in mass due to its velocity but this causes no unexpected deceleration in the probe's trajectory from the sun because that tiny increase in mass (at any velocity other than closely approaching to the speed of light) has no material impact on the shared gravitational attraction between the two bodies.
Which frame of reference is correct to use ? Does it impact what trajectory we measure as a 3rd party observer with a different frame of reference again?