How does the Sun get orbital energy to start orbiting a barycenter?

[Robittybob1]

Well it is generally accepted that the planets orbit the Sun (or the SSB) whatever, they are points real close to each other, near the Sun itself. So do we accept we are on the body that is orbiting the Sun rather that early ideas of the Geocentric SS?

Science has in some way defined a center. I hope we can agree on that. Do we agree that the planets orbit the Sun or the SSB (one or the other you don't have to choose yet)?

Edited February 11, 2015 by Robittybob1

[Mordred]

I'd say it's fair to stick with heliocentric coordinates for the topic at hand.

[whiskers]

If you say the planets orbit the earth, you will have to make a lot of awkward exaggerated "corrections" (old term is epicycles). Changing center to the Sun causes a revolution of simplicity and yet some irregularities remain. Moving on from there to the barycenter is another leap of improvement. If you move to the GC you remove some more irregulairites. You say that it is "generally accepted" that the planets orbit the Sun, it might be more accurate to say that it is "often stated". If you have to pick one physical body in the Solar system from which the orbits of other bodies appear to move in the simplest repeating movements the most like ellipses, you would definitely want to pick the Sun, which has 99% of the mass of the solar system in it. Science has many ways of defining centers. I have found people to be quite hard-pressed to explain what they mean by "orbit" and "center" and are satisifed with statements liike "people used to be wrong saying planets orbit the Earth, now we are right saying the planets orbit the Sun."

I'd say it's fair to stick with heliocentric coordinates for the topic at hand.

Can OP follow that? or is there too much reliance on SSB as if was a real physical thing?

[Mordred]

Truthfully as I understand what he's after which I may be off he's looking for a connection between the sunspots cycles to the planets movements.

 

However that being said there really isn't a connection.

 

I had to do some digging and the root cause is differential rotation which causes electromagnetic magnetic convection currents. The different convection currents has plasma interations that generate a charge.

 

The cycle of the suns differential rotation is 22 years.

 

Differential rotation is a property any spinning plasma gains, the complexity is simply greater due to the suns thermodynamic engine.

 

For the OP here is a detailed analysis of the diffetential rotation in terms of the vorticity flows.

 

http://arxiv.org/abs/1407.0984

 

The coordinate choice makes little difference in the above, so it's more a sidelight conjecture.

 

For further info on differential rotation and its connection to the sunspot cycle, googling "differential rotation pdf" pulls up the more reliable articles.

 

 

Though your discussion on orbitals is good science, I do recommend continuing that discussion.

 

 

Ps forgot to add the magnetic pole reversal is every 11 years, but the differential rotation cycle Is 22 years. The article I posted covers that

 

Lol I forgot he had another thread should have posted this there.

http://www.scienceforums.net/topic/87692-the-ever-changing-suns-magnetic-field/

[Robittybob1]

.... Can OP follow that? or is there too much reliance on SSB as if was a real physical thing?

Either the planets orbit the Sun or the SSB and I hoping someone has determined that, but they are virtually the same to all intents and purposes. So I'm not answering that until I have researched it further.

[Strange]

Either the planets orbit the Sun or the SSB and I hoping someone has determined that

 

You can choose either (or neither) - whatever is most convenient for your purposes.

[whiskers]

Either the planets orbit the Sun or the SSB and I hoping someone has determined that, but they are virtually the same to all intents and purposes. So I'm not answering that until I have researched it further.

Motion is relative. There is no way to "determine" that something is unmoving vs anothing thing being moving. This is a good topic for your research. You might start here with old-fashioned relativity. https://en.wikipedia.org/wiki/Galilean_invariance

[Robittybob1]

Motion is relative. There is no way to "determine" that something is unmoving vs anothing thing being moving. This is a good topic for your research. You might start here with old-fashioned relativity. https://en.wikipedia.org/wiki/Galilean_invariance

The ISS orbits the earth, does it not. You never hear anyone saying "it is the relative motion of the Earth to the ISS that keeps it in space". Can you really try to turn the discussion into one of relative motion? It could be, but if it is and that you are right, does that make my idea is also right? For if you can't tell who is orbiting who, can I just declare the Sun doesn't orbit the SSB but the SSB orbits the Sun?

 

You can choose either (or neither) - whatever is most convenient for your purposes.

Can you prove that it is optional? For wouldn't one be more correct than the other?

[Strange]

The ISS orbits the earth, does it not.

 

Actually, it orbits the sun in a series of epicycles. No, I'm wrong, it orbits the galxy in an even more complex set of eipicycles.

[whiskers]

The ISS orbits the earth, does it not. You never hear anyone saying "it is the relative motion of the Earth to the ISS that keeps it in space". Can you really try to turn the discussion into one of relative motion? It could be, but if it is and that you are right, does that make my idea is also right? For if you can't tell who is orbiting who, can I just declare the Sun doesn't orbit the SSB but the SSB orbits the Sun?

Can you prove that it is optional? For wouldn't one be more correct than the other?

 

It is common to say that the ISS orbits the earth. If they say that it is orbiting the Sun or the SSB they are not wrong. Also, if they say that the ISS and the earth orbit a common ISS/earth barycenter (perhaps imperceptibly close the center of the earth) that is also not wrong. The fact that you "never hear" people saying something only means that people have no reason not to use the most practical and intuitive description of a situation. Also most people don't know much about physics and are just using the description that is in common usage. You "always hear" people talking about the Sun rising and setting - but then you sometimes hear people say that is false it is the earth rotating.

[imatfaal]

Robitty - there comes at point in every model where the assumptions start to significantly alter the precision of predictions. There are also points where one set of assumptions are not worth challenging or trying to minimize because they are swamped by a second set of assumptions (you can insert simplification, imprecision in measurement, rationalization etc in place of assumption in these sentences). That celestial bodies follow simple and unchanging orbits is one of these assumptions

 

Very few calculations will need the more than the sort of accuracy that you get with a simple newtonian calculation based on things orbiting the sun in an otherwise empty solar system. Those that do need more accuracy tend to make sweeping assumptions about other matters in order to keep the complexity within calculational limits. You would also need to carefully consider whether newtonian modelling is the correct choice - should one be using modified newtonian dynamics or heaven forbid GR.

 

Unfortunately the above boils down to having to do a nasty mathematical calculation - ie where is the precision error? If you only know a mass (or more likely a mass ratio) to a significance of a certain number of kilo-tonnes, or a distance to thousands of kilometres then there is little point investing time and effort in crunching other data to a much finer level of accuracy. This is off the top of my head but I think we are only certain of G (newtons gravitational constant) to the third decimal place.

[Robittybob1]

 

It is common to say that the ISS orbits the earth. If they say that it is orbiting the Sun or the SSB they are not wrong. Also, if they say that the ISS and the earth orbit a common ISS/earth barycenter (perhaps imperceptibly close the center of the earth) that is also not wrong. The fact that you "never hear" people saying something only means that people have no reason not to use the most practical and intuitive description of a situation. Also most people don't know much about physics and are just using the description that is in common usage. You "always hear" people talking about the Sun rising and setting - but then you sometimes hear people say that is false it is the earth rotating.

It shows we need to be physically correct and to keep it simple.

If the Sun has 99% of the mass of the SS how is the last 1% going to make it orbit anything real or unreal. The SSB is a calculated point so it is not a physical object but a point in space that moves or is it stationary WRT the SS? Just my instant impression is that it is a moving point. OK make an object as massive as the Sun and make it orbit a constantly moving point, will that take kinetic energy to be added and subtracted?

 

We can say if Jupiter is moved to a different distance the SSB will move but to do that will take an enormous amount of energy applied to the planet, but you didn't do anything to the Sun yet we say it is orbiting a different barycenter,

 

I nearly see your point. OK

[swansont]

It shows we need to be physically correct and to keep it simple.

If the Sun has 99% of the mass of the SS how is the last 1% going to make it orbit anything real or unreal. The SSB is a calculated point so it is not a physical object but a point in space that moves or is it stationary WRT the SS?

 

I don't think you can use the solar system as a reference point for saying something is stationary or not, so this is not a question that makes any sense.

[Robittybob1]

 

I don't think you can use the solar system as a reference point for saying something is stationary or not, so this is not a question that makes any sense.

I did see some coordinate system that used the Solar System, I read the word but left it at that. It might have been the following, so I suppose you define your starting point in time and measure movements from then. So that must be using the SSB as the fixed point. I'll have to brush up on this.

http://en.wikipedia.org/wiki/Barycentric_Dynamical_Time

Barycentric Dynamical Time (TDB) applies to the Solar-System-barycentric reference frame

 

[swansont]

I did see some coordinate system that used the Solar System, I read the word but left it at that. It might have been the following, so I suppose you define your starting point in time and measure movements from then. So that must be using the SSB as the fixed point. I'll have to brush up on this.

http://en.wikipedia.org/wiki/Barycentric_Dynamical_Time

 

 

Solar system barycentric frame uses the barycenter. Which, by definition, is at rest with respect to itself.

[Robittybob1]

 

 

Solar system barycentric frame uses the barycenter. Which, by definition, is at rest with respect to itself.

But can't everything (except EM radiation) be considered at rest WRT itself? That becomes the basis of this discussion , where I was trying to show (even though it is at rest to itself) it is not at rest to the rest of the Solar System and in particular the Sun.

[J.C.MacSwell]

But can't everything (except EM radiation) be considered at rest WRT itself? That becomes the basis of this discussion , where I was trying to show (even though it is at rest to itself) it is not at rest to the rest of the Solar System and in particular the Sun.

For our Solar System, wouldn't the Solar System barycentric frame be the closest thing we have to an inertial frame? (closest and most permanent)

Edited February 11, 2015 by J.C.MacSwell

[whiskers]

But can't everything (except EM radiation) be considered at rest WRT itself? That becomes the basis of this discussion , where I was trying to show (even though it is at rest to itself) it is not at rest to the rest of the Solar System and in particular the Sun.

The SSB is at rest with - and defined by - an *average* position of the matter in the rest of the SS. It is not over time at rest WRT the Sun or any other particular body or particle in the SS.

[Robittybob1]

The SSB is at rest with - and defined by - an *average* position of the matter in the rest of the SS. It is not over time at rest WRT the Sun or any other particular body or particle in the SS.

That is not an easy concept. If the Earth orbits the Sun once a year what is the average position? You could work out its average distance from the Sun. Then what would you do to say something about its average position?

[whiskers]

I wasn't thinking in terms of orbits. The SSB, at any one moment, is at the average of all of the positions of the matter in the solar system, at that moment.

Here's an example of how people figure out solar system motions with the best accuracy - primarily there are no "orbits" here:

http://www.moshier.net/ssystem.html

[Robittybob1]

I wasn't thinking in terms of orbits. The SSB, at any one moment, is at the average of all of the positions of the matter in the solar system, at that moment.

Here's an example of how people figure out solar system motions with the best accuracy - primarily there are no "orbits" here:

http://www.moshier.net/ssystem.html

That certainly shows how complex it gets

 

The principal forces that determine the motions are Newtonian gravitational attractions between the solar system bodies modeled as point masses or spheres. The Newtonian forces are modified by relativistic corrections as described in the first reference (Newhall et al, 1983). The relativistic center of mass of the solar system is constrained to stay at the origin of the coordinate system by adjusting the barycentric location and velocity of the Sun after each integration step.

It is one thing for the mathematicians to "adjust the barycentric location and velocity of the Sun". In my model I would invent this other spot (origin of the coordinates) and have the Sun move location and velocity from there but also allow the CoM to orbit the Sun.

 

Probably not quite said correctly but if you have followed the thread you would know what I mean, but the maths of it are probably beyond me at this stage.

For our Solar System, wouldn't the Solar System barycentric frame be the closest thing we have to an inertial frame? (closest and most permanent)

The analogy I was thinking of was a boat tied to a mooring in a flowing ebbing current, the current being strong enough to drag the mooring mass to and fro but not very far.

So the planets etc circulating the Sun represents the current, the boat would represent the SSB, and the Mooring weight represents the Sun, and the amount it is dragged from spot X is the "wobble".

This would also mean that there is some reaction time involved as well to get the sideways motion of the mass of the sun there would need to be angled vector forces to cause this to happen. (like towing a weight via a rubber band to get the weight to move in a circular motion there would need to be tension applied ahead of the radial lines from the center of the circle

Edited February 12, 2015 by Robittybob1

[whiskers]

That certainly shows how complex it gets

It is one thing for the mathematicians to "adjust the barycentric location and velocity of the Sun". In my model I would invent this other spot (origin of the coordinates) and have the Sun move location and velocity from there but also allow the CoM to orbit the Sun.

 

Probably not quite said correctly but if you have followed the thread you would know what I mean, but the maths of it are probably beyond me at this stage.

The analogy I was thinking of was a boat tied to a mooring in a flowing ebbing current, the current being strong enough to drag the mooring mass to and fro but not very far.

So the planets etc circulating the Sun represents the current, the boat would represent the SSB, and the Mooring weight represents the Sun, and the amount it is dragged from spot X is the "wobble".

This would also mean that there is some reaction time involved as well to get the sideways motion of the mass of the sun there would need to be angled vector forces to cause this to happen. (like towing a weight via a rubber band to get the weight to move in a circular motion there would need to be tension applied ahead of the radial lines from the center of the circle

I don't completely understand, but here's my guess: "Nope".

[Robittybob1]

I don't completely understand, but here's my guess: "Nope".

I thought I'd give you a plus 1 for making me laugh, at the end of a difficult day. Thanks for the interaction, I found your posts quite helpful. Good luck.

[Robittybob1]

I just hope some bright-spark picks it up and runs with it.

[swansont]

But can't everything (except EM radiation) be considered at rest WRT itself? That becomes the basis of this discussion , where I was trying to show (even though it is at rest to itself) it is not at rest to the rest of the Solar System and in particular the Sun.

 

Yes they can (at least in inertial frames). That's the point. You said the barycenter was at rest with respect to the solar system, and then that "solar system" meant barycenter. That's a tautology. It's true by definition. Nothing revealing about it.

 

Everything is moving with respect to the barycenter. Also not particularly revealing, since everything is orbiting it.