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Author Topic:   What is movement and velocity ?
vimesey
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Posts: 1398
From: Birmingham, England
Joined: 09-21-2011


(1)
Message 1 of 6 (634454)
09-21-2011 6:50 PM


Hi there all - I'm a new member of EVC - and a large part of the reason I joined was to learn more about this pretty fascinating place in which we live.
I was reading some of Cavediver's posts about how our universe is comprised of a number of overlapping fields (possibly aspects of one overall field), and that subatomic particles are excitations within those fields at any one point.
What was particularly fascinating was Cavediver's explanation that one field's excitations represented what we perceive as distance. Would it be possible for someone to try to answer for me (an intelligent non-scientist) the following questions:
1. In the context of that explanation of fields, how would all of the various sub-atomic field excitations that make up me (or anything else), moving from what I perceive to be one place to another, be expressed ?
2. How would the expression (in that context) of that movement differ, dependent upon my velocity (in my perceived 3 dimensional terms) ?
3. And moving on from there, (and given what we know about my velocity in space time being C) how is velocity (in 3 dimensional terms) at closer to C (or in a photon's case, at C) expressed in those terms ? In other words, what is the relationship between these fields and time ? (If time can be treated as separate in this context).
These are questions which I think I need to answer, to try to help my understanding of this.
And just as likely, I may need to know why these are ignorant questions, to try to help my understanding of this ;-)
Edited by vimesey, : No reason given.

There aren't many things that shouldn't be questioned, but question the rest.

Replies to this message:
 Message 3 by AZPaul3, posted 09-21-2011 8:50 PM vimesey has replied

  
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Message 2 of 6 (634456)
09-21-2011 7:18 PM


Thread Copied from Proposed New Topics Forum
Thread copied here from the What is movement and velocity ? thread in the Proposed New Topics forum.

  
AZPaul3
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From: Phoenix
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Member Rating: 5.3


Message 3 of 6 (634459)
09-21-2011 8:50 PM
Reply to: Message 1 by vimesey
09-21-2011 6:50 PM


Momentum and Velocity?
I'm sure our spelunking resident physicist will need to make corrections (which will aid in my understanding as well) but let me try this on you first.
I may not be correct in this assessment but I am thinking you are asking for "momentum" rather than "movement". I will go with that assumption until you correct me.
We need a coordinate system. Any will do. Assume a coordinate system.
1. Velocity. Velocity is a vector quantity of a field combining both speed and direction. In our coordinate system, since we are using vector quantities, this is a vector field. In this vector field "velocity" is defined as a change in coordinate values at a specified rate in a specified direction.
2. Movement. Movement is strictly a change in the coordinate values without regard to any other quantity. No direction, no rate. Strictly a change in placement (change in coordinate value) within the field. Obviously, to get from one set of coordinates to another requires other considerations, thus my assumption that your question deals with "momentum" rather than just "movement".
3. Momentum. Momentum is defined as "mass times velocity". And changes in "momentum" relate to how a "force" is applied and for how long it is applied, and the resulting vectors of that application, to an object. Change in momentum will be changes to our coordinate numbers for rate or direction or both.
I'll look forward to others input.
And Welcome to Evc, vimesey!
Edited by AZPaul3, : clarity

This message is a reply to:
 Message 1 by vimesey, posted 09-21-2011 6:50 PM vimesey has replied

Replies to this message:
 Message 4 by vimesey, posted 09-23-2011 5:53 AM AZPaul3 has seen this message but not replied

  
vimesey
Member
Posts: 1398
From: Birmingham, England
Joined: 09-21-2011


Message 4 of 6 (634611)
09-23-2011 5:53 AM
Reply to: Message 3 by AZPaul3
09-21-2011 8:50 PM


Re: Momentum and Velocity?
Hi there Paul, and thank you for the welcome,
I understand now the precise way in which you are using the word "movement", and I'll try to make sure I adopt this use of the word in the future on this forum - it will no doubt help me express myself a little better.
I need to learn how to link to posts in other fora at some point, but the quotation from Cavediver which I found fascinating is this:
"The graviton field is what gives us the concept of distance and space-time geometry. Think about this for a minute - it is the field that defines the distances we measure between objects - whether from your nose to your right big toe, or from your nose to the quasar 3C273!"
So looking at momentum, as you have described it, let's assume that force is applied to the various matter and guage particles that constitute me (someone gives me a deserved kick up the backside) and the distance between me and, say, the door in front of me decreases.
As I understand what Cavediver is saying, what happens is not fundamentally as simple as the x. y, z and t co-ordinates of all of my matter and guage particles changing as a result of the application of the boot on my backside (though I certainly perceive a simple co-ordinate change in the 3 dimensions which I can observe) - there is something far more subtle or complex or both which is happening in the context of the graviton field.
I may be being hopelessy optimistic here, but I would love to have some sort of understanding of the momentum I experience, but in the context of that graviton field.
(And sincere apologies to the guys who use the above terms regularly and know exactly what they mean - I know I'm using them without much of a clue as to their exact meaning, but hopefully this will help people in identifying any mistakes I'm making).
Cheers :-)

This message is a reply to:
 Message 3 by AZPaul3, posted 09-21-2011 8:50 PM AZPaul3 has seen this message but not replied

Replies to this message:
 Message 5 by Son Goku, posted 09-23-2011 5:50 PM vimesey has not replied
 Message 6 by Oli, posted 09-23-2011 6:20 PM vimesey has not replied

  
Son Goku
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Message 5 of 6 (634749)
09-23-2011 5:50 PM
Reply to: Message 4 by vimesey
09-23-2011 5:53 AM


Re: Momentum and Velocity?
Actually getting kicked up the arse is incredibly complicated from a fundamental physics point of view. So this post will be long.
Let's take two metals blocks hitting each other, an approximation to your arse. Fundamentally all matter (basically) is made up of atoms which are a central charge, the nucleus, with electrons going around them. All that will really matter are the electrons.
Electrons are isolated "lumps" of the electron field that fills the entire universe. This field is fermionic, which means that you have to perform a 720 degree rotation for it to look the same again (unlike objects in everyday life which take 360 degrees). Tthe individual lumps of this field, the electrons, are also fermionic.
Like all quantum mechanical particles electrons exist as a probability wave spread over space, rather than existing in one place like in classical mechanics. This probability wave gives the chance of finding an electron in a certain location. The probability wave is usually called a wavefunction.
There is a mathematical result known as the Spin and Statistics theorem which tells us that because electrons are fermionic, their probability waves don't overlap in a certain sense. Specifically if the electrons have the same spin, then the probability of them being in the same place is zero. This means it takes energy to push electrons near each other, because they "exclude" each other. Which is known as the Pauli Exclusion principle.
Due to this, electrons pile up inside atoms and materials, in a certain way, arranging themselves so as to obey the Pauli-Exclusion principle. These arrangements have a lot of energy:
1,000,000,000,000,000 times the energy of typical arrangements you get from things which don't obey the Pauli-exclusion principle.
When one thing hits another it has to fight against this energy to crush it. Without the Pauli exclusion principle most things things would be easy to crush, for instance if I could "switch off" the Pauli exclusion principle in a bar of titanium a baby could easily crush it.
Hence because of this "most" of the energy from the kick can't go into rearranging atomic configurations, so it has to go elsewhere.
Now let's step back for a bit. Since the electrons of the two objects are both just different parts of the electron field, the moment of the kick is just one collection of excitations of this field coming near another collection. Since the electron field is connected to other fields, such as the electromagnetic field, these fields will start getting excited near the point of contact. Basically because there is lots of electrons.
The electromagnetic field's presence will change the way the electron field evolves, and will cause it to redistribute the probabilities among the electrons. During the kick, all the electron field is doing, from an objective point of view, is redistributing the probabilities for the electrons to be in certain locations because of the presence of the electromagnetic field. Due to the Pauli exclusion principle above, very little probability goes to configurations where the material remains in place but is significantly crushed. Most "flows" into configurations where the kicked object as a whole is moved slightly away from the kicking object.
Hence, from our perspective, the kicked object will move away.

This message is a reply to:
 Message 4 by vimesey, posted 09-23-2011 5:53 AM vimesey has not replied

  
Oli
Junior Member (Idle past 4393 days)
Posts: 16
From: United Kingdom
Joined: 04-03-2011


Message 6 of 6 (634753)
09-23-2011 6:20 PM
Reply to: Message 4 by vimesey
09-23-2011 5:53 AM


Re: Momentum and Velocity?
Hi there,
Modern physics is described by two theories: gravity is described by general relativity, and everything else by quantum field theories in the standard model.
In general relativity, the ‘gravitational field’ caused by massive objects defines the geometry of space-time. This geometry is encapsulated in how we measure distance.
For example, imagine finding the distance between two points (x1,y1) and (x2,y2) on a 2D plane (The Distance Formula | Purplemath). The distance s is given by pythagoras theorem in ‘every day’ geometry:
S^2 = (x2-x1)^2 + (y2-y1)^2
However, general relativity tells us that this formula changes in the presence of massive objects. So we put the distribution of matter and energy in to general relativity, and it tells us what formula to use to calculate distance. If we can solve all the equations...
I hope that helps, but bear in mind that general relativity deals with 4 dimensions not just 2. Also, I don’t know how much maths you’ve done, so apologies if this is too hard or too patronising!
Oli
Edit: so in the presence of massive objects all the effects described by Son Goku occur on the background of the different geometry. But no one knows how quantum mechanics works with general relativity (least of all me).
Edited by Oli, : Just saw post by Son Goku.
Edited by Oli, : No reason given.

This message is a reply to:
 Message 4 by vimesey, posted 09-23-2011 5:53 AM vimesey has not replied

  
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