Proposal: A surface moving parallel to itself in one frame is not doing so in all frames.

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Pete

It's not rocket surgery
Registered Senior Member
Tach and I want to discuss the issue of surface orientation, velocity direction, and parallelism under lorentz transforms in a focused one-on-one thread.

I propose we hold a debate, not with the goal of determining a winner and a loser, but of first finding common foundations, then building on those foundations to a mutual conclusion.

As such, this is not really a formal debate, and I think we should get approval from the forum moderators to proceed.

I suggest the following:
Umbrella rules
  1. The debate is between Pete and Tach. No other members may post to the Debate thread.
  2. There is no time limit or post limit.
  3. Both Tach and Pete must remain polite, and discuss the topic in a spirit of mutual discovery.
  4. All direct questions must be responded to in the next post.
  5. Posts may not be edited except:
    • Within 5 minutes of posting
    • For typographical errors only
    Or:
    • If permission is given by the other person by PM or the Discussion thread.
    (Both Tach and Pete have a bad habit of continuing to polish posts after they're up. We'll both have to manage to proofread before posting!)
  6. Posts are made in turn. Once a post is made, we must wait for a response before posting again (again, my bad habit).
  7. Potential rule violations and administrative issues must be discussed in the Discussion thread.
  8. Other posts by Tach and Pete to the Discussion thread should be kept to a minimum:
    • Direct questions from other members may be briefly answered, but extended discussions should be taken to another thread.
    • Other than to discuss Debate administrative issues, Pete and Tach may not address or respond to each other in the Discussion thread.

Discussion tracking
  1. The focus of the debate thread must remain tight.
  2. Debate issues will be listed and tracked in the first post of the debate thread (the tracking list).
  3. Each Debate post must have a heading in bold stating the specific issue addressed by that post.
  4. Post headings must match one of the issues listed in the tracking list.
  5. Initially, the tracking list will only contain the three stages of the discussion as outlined below.
  6. The tracking list will be updated as necessary to reflect the status of the discussion:
    • To tick off the Stages as we progress through them
    • To add side issues as they arise,
    • To track the status of each side issue, eg resolved, active, pending another side issue, abandoned, irreconcilable...
  7. Note that the editing rules (above) apply to the tracking list. It will be Pete's post, but he may only update it with permission from Tach.
  8. When the list needs to be updated, one of us will post a request in the Discussion thread
  9. When the update is mutually agreed, Pete or a moderator will edit the list to suit.


Stages of the Debate
  • Pete will create the Debate thread and make an opening post containing only the tracking list.

Stage 1 - scenario
  1. Pete will then make the first discussion post, setting out a scenario.
  2. Tach will respond with suggestions for improvement, questions for clarification, etc, and we will discuss these until we agree that the scenario is sufficiently well defined and mutually understood.

Stage 2 - methodology
  • We will take one post each to:
    • describe the measurements that we would like to make in each reference frame,
    • define how the measurements will be made
  • We will then discuss the suggested measurements, suggesting improvements, asking clarification, etc until we agree that the set of measurements are sufficiently well defined and mutually understood.
  • No suggested measurement may be refused, unless it can not be sufficiently well defined.
  • Disagreements about how to refer to each measurement must also be resolved at this stage.

Stage 3 - calculations:
  • Tach and Pete will individually prepare calculations for the results of each measurement.
  • When we both indicate readiness, the two analyses will be posted at around the same time.
  • The analyses should be posted directly in the thread if at all possible. If either poster needs to use an off-site document, they should ask first and explain why.
  • We will then discuss any discrepancies (one at a time) between the analyses, using sufficient mathematical rigor to resolve them.

Final Stage - summary and reflection
  • If Stage 3 is completed, or the discussion stalls at any time, Tach and Pete will prepare single independent summary posts, describing our impression of how the discussion went, the conclusions we reached, and what we learned.
  • When we both indicate readiness, the two summaries will be posted at around the same time.
  • Following the summary posts, the Debate thread will be closed.
 
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OK, sounds good.
The only thing that is missing is defining what do you mean by a surface moving parallel to itself. Case and point: does the surface velocity line up with the normal to the surface or with the tangent to the surface ? Or neither?

The second issue is that the debate is for the two of us only, no interventions from the well-known cheerleaders. You and I only.
 
OK, sounds good.
The only thing that is missing is defining what do you mean by a surface moving parallel to itself. Case and point: does the surface velocity line up with the normal to the surface or with the tangent to the surface ? Or neither?
I think that's something that will be resolved when we say exactly what we're going to measure, and nut out exactly what we should call those measurements.
We might find no clear answer to the topic as posed due to its ambiguity, but we should find clear answers to well defined measurements.
The second issue is that the debate is for the two of us only, no interventions from the well-known cheerleaders. You and I only.

Right. I don't think we should keep people out of the discussion thread, but the debate thread is definitely only for the debaters. Added to umbrella rules, to make it explicit.
 
I think that's something that will be resolved when we say exactly what we're going to measure, and nut out exactly what we should call those measurements.
We might find no clear answer to the topic as posed due to its ambiguity, but we should find clear answers to well defined measurements.

Well we just wasted a monumental amount of time on this issue, I do not plan to waste more time on it. So, I suggest that we tighten the scope. How does:

"The zero angle between the tangent plane of a microfacet and the tangent velocity as measured in the axle frame transforms into a zero angle through a boost along the x-axis in the ground frame" sound?
For: T, Against: P.
 
Please an explanation:
It is a movement of an object in different reference frame?
Or a relative motion between two objects in different reference frame?
 
Well we just wasted a monumental amount of time on this issue, I do not plan to waste more time on it. So, I suggest that we tighten the scope. How does:

"The zero angle between the tangent plane of a microfacet and the tangent velocity as measured in the axle frame transforms into a zero angle through a boost along the x-axis in the ground frame" sound?
For: T, Against: P.

Fine, except that it's too long for a thread title... I'll make the thread with some abbreviated version in the title, and full topic in the first post.
Since you prefer the more complex case of the rolling wheel, would you like to write the scenario? Or shall I?
 
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Fine, except that it's too long for a thread title... I'll make the thread with some abbreviated version in the title, and full topic in the first post.
Since you prefer the more complex case of the rolling wheel, would you like to write the scenario? Or shall I?

Done.
 
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Links:

[thread=111142]Debate Thread[/thread]
[thread=111143]Discussion Thread[/thread]
 
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