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

[Robittybob1]

Do we orbit the center of mass of the solar system or just the center of mass between the Sun and The Earth? It was discussed on another thread on the forum but I've lost track of it. So if the two biggest objects in our Solar System have a Barycenter outside of the radius of the Sun then would Mercury be orbiting this center of mass as well?
Maybe that is the solution to the 3 body problems - do we have to go back to the combined Center of mass and orbit that.

Even if we say that Mercury orbits the center of the Sun, and the Sun orbits around the barycenter (between it and Jupiter) that would mean Mercury is orbiting in some unusual way too. How does that start off? For the proto-Sun must have been sitting in the middle of the protoplanetary disc so how does it get orbital energy to start orbiting a barycenter?

 

Please I would still like someone to answer these question if possible.

 

Here is my first attempt:

As the mass of material that formed Jupiter gathered together the mass of the Sun would gravitate toward it, but that mass is orbiting so it would drag the Sun behind it gradually build up momentum, so that means jupiter would have to migrate inward losing gravitational potential energy to make up for the energy transferred to the Sun.

[Mordred]

All celestial objects orbit common centers of mass. However as our sun is so massive it is extremely close to the center of Mass.

 

 

This is covered by Newtons shell theorem.

 

http://www.google.ca/url?sa=t&source=web&cd=2&ved=0CB4QFjAB&url=http%3A%2F%2Fwww.math.ksu.edu%2F~dbski%2Fwritings%2Fshell.pdf&rct=j&q=shell%20theorem&ei=nWXVVL7cMteWyQS8mIKgDg&usg=AFQjCNF5JJzSaMChBAeVVNdIhIBdsO-sCg&sig2=tyJkh5eEcrMDNuUCJMbp_g

[Robittybob1]

That would be true initially but once Jupiter starts getting real massive the Solar System (SS) becomes lopsided wherever Jupiter is there is more mass on that side, so unless the Sun was orbiting a common barycenter too it would be drawn toward Jupiter.

Just to check I got my facts straight:

Barycenter in Wikipedia: http://en.wikipedia.org/wiki/Barycentric_coordinates_%28astronomy%29

 

The barycenter (or barycentre; from the Greek βαρύ-ς heavy + κέντρ-ον centre + -ic[1]) is the point between two objects where they balance each other. For example, it is the center of mass where two or more celestial bodies orbit each other.

 

But before Jupiter formed the Sun wasn't orbiting any barycenter with Jupiter, so explain what makes the Sun start orbiting?

If we look at the data collected we see a complex pattern.

 

http://en.wikipedia.org/wiki/Barycentric_coordinates_%28astronomy%29#mediaviewer/File:Solar_system_barycenter.svg

Just glancing at diagram you see they are approximately 12 year loops so one could assume the major influence on this pattern is the 11.86 year orbital period of Jupiter. http://en.wikipedia.org/wiki/Jupiter

 

Jupiter's mass is 2.5 times that of all the other planets in the Solar System combined—this is so massive that its barycenter with the Sun lies above the Sun's surface at 1.068 solar radii from the Sun's center...... Jupiter's ... mass is 0.001 times the mass of the Sun.

 

 

Look I have found an article that asks the same question as I am.

http://solarchords.com/solar-chord-science/astrophysicists-earth-orbit-sun-or-barycentre/

 

At the heart of Frederick Bailey’s Solar Chord Science is the sometimes debated question of what is it that planet Earth primarily orbits – is it locked in fixed elliptical orbit of the Sun, or does Earth, and the Sun, (and all the other planets) orbit the barycentre of the entire solar system.

So I have to look at that now. But if I'm not mistaken the SS barycenter isn't a stationary point either, it would be shifting depending on the arrangement of the of the planets in particular Jupiter.

 

The sun is included too – it travels in an ellipse around the solar system’s barycenter.

Edited February 7, 2015 by Robittybob1

[Mordred]

Yes the barycenter shifts as the planets orbit they all have a contribution to the barycenters location. Those links included the related calculations.

 

run the calculations at different planet locations within their orbits

you will quickly see that the barycenter will be at different points depending on the planets locations relative to each other

If you want to run the calculations don't forget orbits are elliptical. Keplers laws provide a decent approximation for our solar system. However it assumes the sun is the center of mass.

 

 

On a related topic center of gravity also applies to ship stability. A lower center of gravity means a more stable ship. Hence placing the bulk of a ships weight near the keel leads to less rocking. Just an FYI.

Edited February 7, 2015 by Mordred

[Robittybob1]

one more: https://astrogeek.wordpress.com/2007/01/08/technicality-jupiter-does-not-orbit-the-sun/

 

Another wikibit: if all of the planets are lined up on one side of the Sun, the common barycenter would be 500,000 kilometers above the surface.

So what doesn't make sense as yet is that as the barycenter alters when the planets rearrange but what makes the Sun orbit at different rates? Does its orbital energy continually change? I can see how it might have been brought up at some stage but then how does it get rid of it?

 

For those who like a visual representation:

 

SkyMarvels™ SOLAR SYSTEM BARYCENTER (celestia celestia4all)

Only thing I can't get was them saying "When Jupiter and Saturn are on the one side the Sun must recede from the barycenter to offset these planet's significant mass". How can it? The barycenter can move but the Sun, can it be moved? In fact when both of them are on the same side together the Sun would tend to move toward Jupiter and Saturn, gravity would not make the Sun recede from them!

Edited February 7, 2015 by Robittybob1

[Mordred]

Think Newtons laws. Then realize that force is a vector quantity. As you have different planet orientations the vector sum of the gravitational force at the barycenter will also be different values.

[Robittybob1]

Think Newtons laws. Then realize that force is a vector quantity. As you have different planet orientations the vector sum of the gravitational force at the barycenter will also be different values.

I'm getting the picture now.

[Mordred]

Ok good, just a side note the influence planets have on their parent star causes wobbles in the star. Makes looking for those wobbles incredibly useful in our search for planets.

[swansont]

For the proto-Sun must have been sitting in the middle of the protoplanetary disc so how does it get orbital energy to start orbiting a barycenter?

This is an ill-formed question. The sun was never stationary amongst a bunch of stationary matter in a disc. There was already kinetic and potential energy in the systems.

 

The existence of a gravitational force means there is potential energy already present.

[Robittybob1]

This is an ill-formed question. The sun was never stationary amongst a bunch of stationary matter in a disc. There was already kinetic and potential energy in the systems.

 

The existence of a gravitational force means there is potential energy already present.

But do you know if it was as lopsided as it is today with the two big gas giant planets Jupiter ans Saturn especially when they are on the same side of the solar system? I have never seen any suggestion before that this was the case.

I understand about the angular momentum and the gravitational potential in the early proto-sun/protoplanetary disc, but it is the mass distribution imbalance (resulting from the formation of the massive planets) that I was question questioning.

The Sun doesn't fall back to balance this, no, but is always drawn toward the imbalanced forces, but the planets are moving and hence the Sun begins wobbling.

Now you tell me if you think I have come to an ill formed conclusion please? I don't think the barycenter of the SS is a stationary point in the SS. Am I right or wrong about that?

[swansont]

But do you know if it was as lopsided as it is today with the two big gas giant planets Jupiter ans Saturn especially when they are on the same side of the solar system? I have never seen any suggestion before that this was the case.

 

What is the suggestion that it wasn't?

[J.C.MacSwell]

 

 

So I have to look at that now. But if I'm not mistaken the SS barycenter isn't a stationary point either, it would be shifting depending on the arrangement of the of the planets in particular Jupiter.

It should shift only due to momentum and outside influences, but otherwise should be on a steady path. Conservation of momentum.

 

I don't understand the claims in the link

 

http://solarchords.com/solar-chord-science/astrophysicists-earth-orbit-sun-or-barycentre/

Why would the inner planets orbit the barycenter?

As I stated in a different thread:

"Taking the 3 body problem of Sun, Jupiter, and Mercury, If we placed Jupiter far enough away the barycenter would lie outside Mercury's orbit. I think Mercury would still be in stable orbit about the Sun in that case, though of course the Sun and Jupiter would still essentially orbit about the (new) barycenter."

What am I missing? Surely having Jupiter further way would give it less influence on Mercury's orbit (during any one orbit period)

Edited February 7, 2015 by J.C.MacSwell

[Robittybob1]

It should shift only due to momentum and outside influences, but otherwise should be on a steady path. Conservation of momentum.

 

I don't understand the claims in the link

 

http://solarchords.com/solar-chord-science/astrophysicists-earth-orbit-sun-or-barycentre/

 

Why would the inner planets orbit the barycenter?

 

As I stated in a different thread:

 

"Taking the 3 body problem of Sun, Jupiter, and Mercury, If we placed Jupiter far enough away the barycenter would lie outside Mercury's orbit. I think Mercury would still be in stable orbit about the Sun in that case, though of course the Sun and Jupiter would still essentially orbit about the (new) barycenter."

 

What am I missing? Surely having Jupiter further way would give it less influence on Mercury's orbit (during any one orbit period)

If Jupiter moved further away the barycenter between the the Sun and Jupiter would get further away too, but Jupiter's influence on the movement of the Sun would diminish. The over all influence is based more on the force of the gravitation attraction.

 

What is the suggestion that it wasn't?

As I said originally "For the proto-Sun must have been sitting in the middle of the protoplanetary disc so how does it get orbital energy to start orbiting a barycenter?"

When the matter of the protoplanetary disc was more evenly distributed the SS barycenter would not have swirled around as it does on a 12 yearly cycle.

My prediction is that it may have moved a bit but less than it does now.

Do you agree with that prediction?

 

(It was posted a bit early in the morning, sorry for the spelling errors)

Edited February 7, 2015 by Robittybob1

[J.C.MacSwell]

If Jupiter moved further away the barycenter between the the Sun and Jupiter would get further away too, but Jupiter's influence on the movement of the Sun would diminish. The over all influence is based more on the force of the gravitation attraction.

 

Agree, but that doesn't change the fact that I think the conclusions in the link are incorrect. I don't believe Mercury orbits the common mass of the Solar System, but more so the Sun itself.

[Mordred]

If Jupiter moved further away the barycenter between the the Sun and Jupiter would get further away too, but Jupiter's influence on the movement of the Sun would diminish. The over all influence is based more on the force of the gravitation attraction.

 

As I said originally "For the proto-Sun must have been sitting in the middle of the protoplanetary disc so how does it get orbital energy to start orbiting a barycenter?"

Went the matter of the protoplanetary disc was more evenly distributed the SS barycenter would not have swirled around as it does on a 12 yearly cycle.

My prediction is that it may have moved a bit but less that it does now.

Do you agree with that prediction?

Let's look a bit further back in time. How does a plasma cloud start compressing to start a solar system formation?

 

For that you need to look at Jeans mass.

 

http://en.m.wikipedia.org/wiki/Jeans_instability

[Robittybob1]

Agree, but that doesn't change the fact that I think the conclusions in the link are incorrect. I don't believe Mercury orbits the common mass of the Solar System, but more so the Sun itself.

That could be saying much the same thing if the Sun is orbiting the common barycenter and Mercury is orbiting the Sun, it certainly could explain why Mercury's orbit is more eccentric than the other terrestrial planets.

For example the Moon orbits the Earth and also orbits the Sun. So does the Moon orbit the SS barycenter. It is hard to compute that by thought only.

Let's look a bit further back in time. How does a plasma cloud start compressing to start a solar system formation?

 

For that you need to look at Jeans mass.

 

http://en.m.wikipedia.org/wiki/Jeans_instability

Another day another thread maybe.

Edited February 7, 2015 by Robittybob1

[Mordred]

Fair enough I posted a simulator on the thread in classic forum

http://www.orbitsimulator.com/gravity/articles/ssbarycenter.html

 

I'll repost here

[Robittybob1]

Did we answer the OP question? I felt it has not yet been answered in a physical way. It is easy to calculate the barycenter between two masses but how do you explain the orbital energy? Every few years the Sun's core is spinning and orbiting the very barycenter of the SS, so we can't just put it down to some velocity that has built up over the millennia. Is there any actual proof that the Sun is orbiting at all?

There is a definite wobble on a 11.86 year period. But is that wobble actually orbital motion?

[Strange]

but how do you explain the orbital energy?

 

What needs explaining? Are you under the impression that it takes energy to keep things in orbit?

[swansont]

Did we answer the OP question? I felt it has not yet been answered in a physical way. It is easy to calculate the barycenter between two masses but how do you explain the orbital energy?

 

The system wasn't at rest to begin with. What exactly needs explaining?

[Robittybob1]

 

What needs explaining? Are you under the impression that it takes energy to keep things in orbit?

Things have to have a certain amount of orbital energy don't they? The Earth transfers momentum and energy to the Moon and the Moon is being tidally accelerated and hence it drifts away from the Earth. It won't do this without the addition of energy.

This energy is at the expense of the Earth's rotational energy. So I can picture that one OK, but what makes the Sun orbit the SS barycenter?

 

In my impression this must be from the gravitational acceleration from the planetary masses, but that would mean the movement is radial not tangential. Radial movement is noticed as a wobble which is alright.

It is more like the SS barycenter orbits the Sun and the Sun is continual falling toward that ever-shifting point. (I believe that is the correct answer). The barycenter will always be roughly* on line between Jupiter and the center of the Sun and as Jupiter orbits the Sun the barycenter orbits the Sun as well. (* it will be slightly influenced by the position other planets as well)

I thought for a moment this could explain why the equatorial region of the Sun rotates more rapidly than the poles, but I've changed my mind for I'm not certain of the mechanism yet.

Edited February 8, 2015 by Robittybob1

[J.C.MacSwell]

Things have to have a certain amount of orbital energy don't they? The Earth transfers momentum and energy to the Moon and the Moon is being tidally accelerated and hence it drifts away from the Earth. It won't do this without the addition of energy.

This energy is at the expense of the Earth's rotational energy. So I can picture that one OK, but what makes the Sun orbit the SS barycenter?

 

In my impression this must be from the gravitational acceleration from the planetary masses, but that would mean the movement is radial not tangential. Radial movement is noticed as a wobble which is alright.

It is more like the SS barycenter orbits the Sun and the Sun is continual falling toward that ever-shifting point. (I believe that is the correct answer). The barycenter will always be roughly* on line between Jupiter and the center of the Sun and as Jupiter orbits the Sun the barycenter orbits the Sun as well. (* it will be slightly influenced by the position other planets as well)

I thought for a moment this could explain why the equatorial region of the Sun rotates more rapidly than the poles, but I've changed my mind for I'm not certain of the mechanism yet.

The SS barycenter orbits the Galaxy, but should otherwise be on a steady path.

[whiskers]

Recently i spent some time thinking about all this with one of the media flaps about how wrong some % of people are about whether the Earth orbits the Sun or vice versa. Here's what I came up with: The very idea of "A orbits B" is pre-Newtonian. It reached its apex with Kepler. Once we get the idea of forces, so-called "orbits" turn out to be derivative or merely apparent. The geocentric and heliocentric are simply *models* and have utility for particular practical problems - certainly neither is "true" or "false" thus geocentrists cannot in fact be labeled "wrong" (though in nearly all cases they will turn out to be mighty unsophisticated). We can call the solar system barycenter the "true center" if we like but it is orbiting with other stellar system barycenters around the galactic core and so on and so on.

 

Momentum and kinetic energy are completely related to which coordinate system one measures them in. They might be called "accounting tricks".

 

Here's a comment in a book by Einstein scoffing at geo vs heliocentrism.

 

https://pbs.twimg.com/media/B9XLht-IYAA7md0.jpg:large

[Robittybob1]

The SS barycenter orbits the Galaxy, but should otherwise be on a steady path.

But that is where it is wrong isn't it? If the Sun was on its own just being orbited by Jupiter and Jupiter and the Sun were behaving like two binary stars orbiting a barycenter I could agree, but when the star was stationary and another body the size of a planet is captured by it from the perspective of the star the barycenter orbits it, for there is no mechanism that the planet can give the star any lateral motion to the line between them.

I'll have to see if this has been discussed by anyone else.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.246.5726&rep=rep1&type=pdf

 

There doesn't seem to be any problem with thinking the Earth-Moon barycenter orbits the Sun. The Earth-Sun barycenter will be in a different location to the Sun-Jupiter barycenter, so it is hard to think that the Sun is orbiting the Earth-Sun barycenter on a yearly cycle and the Sun-Jupiter barycenter on a 11.86 year cycle, but it would not be hard to think of these barycenters orbiting the Sun, sometimes aligning and sometimes on the opposite side of the Sun. So the net effect is a stirring of the gases of the Sun on a 12 yearly cycle. This effect would only happen if the Sun is chasing the SS barycenter rather than orbiting the SS barycenter.

So that makes the Sun orbit this other spot (let's call it the "RB spot") on a 12 yearly cycle. This circular motion interrupted by periods where the RB spot, the SS barycenter and the center of the Sun coincide would result in a circulation (I was able to demonstrate this simply by putting some peppered water in a bowl and moving the bowl in circular swirling motion as the SS barycenter moves in relation to the core of the Sun, and then stopping, the water ended up rotating in the bowl yet the bowl had not rotated).

Edited February 9, 2015 by Robittybob1

[Mordred]

Gravity works. If you introduce a new body of sufficient mass Then the barycenter will shift. The new barycenter becomes the new center of mass.

 

 

I'm really not sure what your looking for in the above. You have two main factors conservation of momentum and gravity.

How the sun and planets rotate is conservation of angular momentum.

 

During formation all the plasma interactions develop a swirl effect. It's pretty near impossible to compress a gas without developing angular momentum interactions. As that plasma contracts then this spin increases. Any interactions later on can influence this rate.

 

Now there is something called gravitational tidal locking where the gravity of one body can influence the spin of another object. Mercury is totally locked by the sun for example. However Jupiter does not tidally lock the sun. The Barycenter can influence the rotation of the sun in theory, however it's spin is still dominated by its conserved angular momentum.

In point of fact the planets have a far better chance of being tidally locked than our massive sun. F=ma after all.

 

 

As a side note the Earths axis rotation is regularly influenced. Usually by extremely small amounts by meteor strikes and nearby misses.

But also from the moon. our day is roughly 1.7 milliseconds longer than a century ago.

 

http://en.m.wikipedia.org/wiki/Earth's_rotation

All forces and particle interactions contribute to conservation of angular momentum. To calculate a planets spin that is not tidally locked. Requires knowing the planets entire history. Good luck with that lol

 

 

Here is a good experiment. Get a 20 kg ball bearing and several marbles.

 

Place the bearing on the center of a trampoline. Then roll the marbles toward the bearing.

 

It's a handy trick to visualize barycenter effects

Edited February 9, 2015 by Mordred