- #36
stanz123
- 13
- 0
Sorry - when I re-read *your* post I saw nothing in it like "name-calling"- donʻt know what I was imagining. I withdraw and apologize for that comment! But not for the physics!
Which earlier post?stanz123 said:Rather than name-calling, please read my post more carefully. It was written in response to an earlier post that did, in fact, talk about rotation of the proto-nebula.
D H said:Which earlier post?
A couple of points about using this forum, stanz123.
1. Please think twice about dredging up old threads -- and this is a very old thread. Look at the dates by the posts.
2. Please use the quote button when you are replying to some post, particularly if the post to which you are replying is not the most recent post in the thread. That quote gives the essential context that the readers of your post need in order to know what you are talking about. I still don't know the earlier post about you are writing.
DaveC426913 said:1] This thread is 4 years old.
2] Who suggested that nebulae behave the way you are saying?? You are describing the solar system as a spinning top - with all masses - including those above and below the protoplanetary disc - orbiting the common protoplanetary axis! No sane scientifically-educated person thinks that. Certainly no one in this thread suggested such a thing.
Kurdt said:There are other forces at work in the disk as well as gravity. There is a lot of self-interaction that is not fully understood. I think you're neglecting this.
stanz123 said:My question was about the evolution of a nebula into a disk, and several of the suggested processes implied such a spinning-top rotation.
stanz123 said:Looking at a particle at high "latitude", in order to have stable rotation of the nebula as a whole, that particle would have to rotate in a small circle about the rotation axis.
DaveC426913 said:Just so we're clear: there is nothing wrong with spherical nebulae evolving into a disc nebula.
But this:
...is not it. So I don't know why you put it forth.
In a spherical nebula, all particles will follow their own path in orbit around the centre of mass.
stanz123 said:I guess I really wasnʻt making myself clear. The point of my comment was that I did *not* think that a low-density nebula could rotate as a cloud. I made that statement as a horrible example, to illustrate how wrong such an idea must be.
DaveC426913 said:Yes, that was obvious. I/we did not misinterpret that.
But since you don't purport it, and none of us purport it, it was a herring of the reddest kind.
stanz123 said:Thatʻs all?!
DaveC426913 said:Everything else you said I have no issue with (mostly because it's beyond my ken :blush:).
Chronos said:The problem with most such ideas is they tend to violate a well established principle of physics right out of the box. Lacking a reasonable, and well supported, explanation for such a 'violation' is the usual reason for dismissing them out of hand.
Time dilation does not violate any well established principles of physics - only once-upon-a-time believed but now understood to be wrong principles.stanz123 said:Another problem, unfortunately, is that a few generally-accepted hypotheses also violate well-established principles of physics but are still accepted because everybody knows they must be right. Like the relativistic time-dilation paradox.
russ_watters said:Time dilation does not violate any well established principles of physics - only once-upon-a-time believed but now understood to be wrong principles.
Vanadium 50 said:I think a) this thread is drifting, and b) it would be good for people to read the stickies in the Relativity sub-forum.