Earth Revolving Around the Sun but not the other way around?

[PDQ]

I find it strange how commonly this is said. The Earth revolves around the Sun but the Sun also revolves around the sun. Saying the sun doesn't revolve around the earth is like saying you pushing against the earth doesn't mean the earth is pushing against you(reference Newton's third law). Or to put it another way, it's a relative frame of reference(reference Einstein's assumptions for relativity to hold). Since there is no known absolute fixed point in the universe(even the sun moves), it can't be said that one isn't true. With inertial frames of reference, whether you stay still and something move forwards or it stays still and you move backwards(ignoring the nuances of walking), it's indistinguishable and the difference is only meaningful within the context of the surface

The idea that a small object is the one revolving around the bigger one seems to be simply a convention. If you assumed the earth to be the center, the Sun would be the one revolving around the earth. However, all the other planets would still revolve around the Sun. So the convention that the earth revolves around the sun is really only for the simplicity of saying that all planets revolve around the sun, but the opposite could be said of any one entity(you can't say it's revolving around all of them because you can only have one of them fixed at a time)

In a nutshell, motion is relative, so both are dependent on the assumption of which to take as fixed(which neither are with respect to the known matter of the universe nor is there any known absolute coordinates).

So why do people say it?(I'm putting this as philosophy since it has to do with perspective rather than arguing the facts).

[westway50]

well everything does revolve around the sun. if the sun started to move in one direction, all the planets will then have a different rotation. but if you move one planet, only it will change its course and the other planets will not be affected. its because of the sun's gravity and circular motion

[batanga]

I see where you're coming from, but the attraction is so very miniscule it's irrelevant in the big picture and because if you say it like that the laypeople won't understand.

[PDQ]

well everything does revolve around the sun. if the sun started to move in one direction, all the planets will then have a different rotation. but if you move one planet, only it will change its course and the other planets will not be affected. its because of the sun's gravity and circular motion
I'm not saying that the earth doesn't revolve around the sun. Only the problem is that people say that the opposite isn't true, when both are simultaneously true in a sense.

If the sun moved in another direction, if we held the earth's position as constant(which is a perfectly valid way due to a lack of absolute coordinates in space), then you would simply see the earth change it's orbit around the earth.

Both being true isn't a coincidence, it's a necessity. Any planet that can be viewed as revolving around the sun must also be viewable as being revolved around by the sun.

I see where you're coming from, but the attraction is so very miniscule it's irrelevant in the big picture and because if you say it like that the laypeople won't understand.
The attraction isn't really miniscule, it's exactly the same. It's Gm1m2/r^2 for both. I'm not talking about the revolution about the center of mass for the 2 body system(which the Sun would be closer to and have a much smaller radius, but their revolution relative to each other and thus the "relative frame of reference"

I can see where you're going with the practical argument, but I'd rather people just say that the earth revolves around the sun to simplify things, since including the statement that the sun doesn't revolve around the earth isn't true. Omitting the truth is better than including a falsehood.

The discovery wasn't so much that the Sun doesn't revolve around the earth so much as the Earth isn't a universally fixed center of all things revolving in the universe.

[Juno]

I find it strange how commonly this is said. The Earth revolves around the Sun but the Sun also revolves around the sun. Saying the sun doesn't revolve around the earth is like saying you pushing against the earth doesn't mean the earth is pushing against you(reference Newton's third law). Or to put it another way, it's a relative frame of reference(reference Einstein's assumptions for relativity to hold). Since there is no known absolute fixed point in the universe(even the sun moves), it can't be said that one isn't true. With inertial frames of reference, whether you stay still and something move forwards or it stays still and you move backwards(ignoring the nuances of walking), it's indistinguishable and the difference is only meaningful within the context of the surface

The idea that a small object is the one revolving around the bigger one seems to be simply a convention. If you assumed the earth to be the center, the Sun would be the one revolving around the earth. However, all the other planets would still revolve around the Sun. So the convention that the earth revolves around the sun is really only for the simplicity of saying that all planets revolve around the sun, but the opposite could be said of any one entity(you can't say it's revolving around all of them because you can only have one of them fixed at a time)

In a nutshell, motion is relative, so both are dependent on the assumption of which to take as fixed(which neither are with respect to the known matter of the universe nor is there any known absolute coordinates).

So why do people say it?(I'm putting this as philosophy since it has to do with perspective rather than arguing the facts).

To put it in the context of the bolded, a more accurate comparison would be to say an elephant stepping down on a mouse is also met with the force of the mouse's mass pushing pack. But clearly the two forces are incredibly unequal and the mouse's mass will cede in the form of a pancake.

The largest mass in this solar system is the star, which obviously exerts the greatest gravitational pull, stringing along all manner of much smaller objects like the planets. If you subjectively decide that your axis is the earth, sure you could say the sun is orbiting the earth, but why would you? The sun is not orbiting the earth as it is not affected by the earth's gravitational field, it only appears that way when standing on the earth. From an objective outside observer, however, it's just not the case, and science is not supposed to be subjective.

But it's an interesting POV I haven't come across before, so thanks for the food for thought.

[PDQ]

To put it in the context of the bolded, a more accurate comparison would be to say an elephant stepping down on a mouse is also met with the force of the mouse's mass pushing pack. But clearly the two forces are incredibly unequal and the mouse's mass will cede in the form of a pancake.

The force at work is exactly the same, it's the result that's different. 10 lb against a mouse might crush it, but 10lb on a elephant's foot would be relatively light.

The largest mass in this solar system is the star, which obviously exerts the greatest gravitational pull, stringing along all manner of much smaller objects like the planets. If you subjectively decide that your axis is the earth, sure you could say the sun is orbiting the earth, but why would you? The sun is not orbiting the earth as it is not affected by the earth's gravitational field, it only appears that way when standing on the earth.

1. Gravitational "fields", like all fields, are an abstraction to show potential independent of other objects(a "disturbance in the force" as my EMF professor put it). It's not something really there. In reality, it boils down to a two body system with a force existing between them and motion occurs, with the relative motion dependent on the observer.
2. The sun is affected by the earth's gravitational field, all matter in the universe is.

From an objective outside observer, however, it's just not the case, and science is not supposed to be subjective.
As Einstein points out, there is no such thing as an "objective outside observer", every frame of reference is bias by it's own motion. That's why his theory is called "relativity". There's no known way of absolutely standing still in the universe. If all the heavenly bodies were moving a million mph uniformly in one direction, it would be impossible to tell and therefore, scientifically meaningless Even relativity wouldn't apply because it only deals with relative motion.

Furthermore, it's not one object, it's two. By tracking the sun from a distant galaxy to see the relative motion, you're setting it as fixed. You could view it as a two body system(well a multiple body system), and view the center of mass between them and notice that both are actually revolving around such a center(albeit the sun would move in a much smaller circle). I think that's an accurate depiction.

[wiggely]

the earth does revolve around the sun. it can do this even if the sun is moving. something doesn't have to remain still for the revolving to occure.

[PDQ]

the earth does revolve around the sun. it can do this even if the sun is moving. something doesn't have to remain still for the revolving to occure.
I never said it didn't. My point is that the sun does revolve around the Earth because there is no such thing as fixed coordinates in space. We say the Sun is moving relative to the other matter in the universe, but in the wholeness of empty space, there is no way to tell if something is moving or staying still. The notion of staying still is meaningless without an absolute coordinate system which cannot be determined.

Just like if you think you're staying still in space and someone passes you at a constant velocity, you would probably think that he's moving past you. Whereas if he thinks he's staying still(which once again, there's no real way to tell who's right unless you make an assumption of what staying still means), he would think the opposite is true. Both are true. You can't say person A is moving past person B but person B is not moving past person A because it's a matter of perspective. Revolving around something takes the perspective of the object being revolved around.

The very term "revolve around" takes the perspective relative to the object being revolved around.

Also note that I'm not suggesting that the Earth doesn't rotate, for that can be determined by centripetal motion and the fact that I'm supposing the center of mass of the earth is fixed, not that the Earth isn't revolving. Relativity only suggests that motion and fixed position can't be determined for linear motion. The rotation of the Earth is of course rotational movement which requires the constant changing of direction.

I'm not putting forth a geocentric view because even if we held the earth as fixed, it wouldn't make any other planet or star revolve around the earth.
Edit: I found this quote by Ratzinger today which seems to capture my thoughts(not that he's exactly an authority on the subject):
According to [Ernst] Bloch, the heliocentric system – just like the geocentric – is based upon presuppositions that can’t be empirically demonstrated. Among these, an important role is played by the affirmation of the existence of an absolute space; that’s an opinion that, in any event, has been cancelled by the Theory of Relativity. Bloch writes, in his own words: ‘From the moment that, with the abolition of the presupposition of an empty and immobile space, movement is no longer produced towards something, but there’s only a relative movement of bodies among themselves, and therefore the measurement of that [movement] depends to a great extent on the choice of a body to serve as a point of reference, in this case is it not merely the complexity of calculations that renders the [geocentric] hypothesis impractical? Then as now, one can suppose the earth to be fixed and the sun as mobile.”
Now, I'm not Christian(more specifically I'm Buddhist), so I'm not doing this to defend the church, nor do I really care what the Bible says about the subject, but the point is what I'm trying to get at.

[wiggely]

I never said it didn't. My point is that the sun does revolve around the Earth because there is no such thing as fixed coordinates in space
agreed, have you read einsteins thoughts on where scientific thought comes from (off topic)? he's my favorite science/philosopher

[|)/-\\/\/|\|]

They are both revolving around each other actually. However the sun is moving in a much slower and almost unnoticeable rate since earth's mass is negligible w.r.t the sun.

[wiggely]

They are both revolving around each other actually
technically thats impossible. but as the op/einstein pointed out, because of relativity the sun could be said to revolve around the earth. they can't both revolve around each other simutaniously.

[Dionysus]

Well, from a kinematic perspective, what's revolving around what is largely a matter of convenience. Ever try to map out the motion of all the planets and the sun assuming the Earth is stationary?

That said, even when the kinematics makes sense in any relative sense, often the energy on these frames would be absurd. For instance, say I have a propeller on a pole fixed to the Earth. I spin the propeller with some force using up some energy (transfer of energy). Now, you can think of it as me spinning the entire universe on an axis that is fixed at a propeller arm, but how much energy did I actually use up? Did I really spin all the matter in the universe (save the propeller) with a few newtons?

Of course, you are just mentioning relative kinematic frames and perhaps special relativity (which doesn't mention accelerations at all). All, I'm saying is that energy in some frames make more sense than others. (I'm having bad memories of nuclear and particle physics now. :arg)

[|)/-\\/\/|\|]

technically thats impossible. but as the op/einstein pointed out, because of relativity the sun could be said to revolve around the earth. they can't both revolve around each other simutaniously.


Actually they are. Take a pen and spin it. The edges at the pen are revolving around each other. The same when it comes to earth sun. However the sun, the heavier edge, is moving in a much slower speed.

[PDQ]

Well, from a kinematic perspective, what's revolving around what is largely a matter of convenience. Ever try to map out the motion of all the planets and the sun assuming the Earth is stationary?

That's my point though, it's a matter of convenience/convention, not necessity. Just like if two people were running at the same speed in the same direction on a flat plane, you could view the both of them to be not moving and not have any effect on the equations(of course the plane would have to be considered moving). But it doesn't make one more true than the other. It's more complex to use one, but that doesn't mean you can say it's not true.

That said, even when the kinematics makes sense in any relative sense, often the energy on these frames would be absurd. For instance, say I have a propeller on a pole fixed to the Earth. I spin the propeller with some force using up some energy (transfer of energy). Now, you can think of it as me spinning the entire universe on an axis that is fixed at a propeller arm, but how much energy did I actually use up? Did I really spin all the matter in the universe (save the propeller) with a few newtons?

Of course, you are just mentioning relative kinematic frames and perhaps special relativity (which doesn't mention accelerations at all). All, I'm saying is that energy in some frames make more sense than others.
As I said above, if we viewed every object in the universe to be moving half the speed of light in one direction, it would add an absurd amount of energy to the equation. But that doesn't make it wrong. Most of the contexts I hear this claim that the sun doesn't revolve around the earth isn't from someone doing calculations, rather it's just a claimed fact, which just isn't true. Certainly we're allowed to take the simplest model that gives the same results, just like we wouldn't add 3 to each side of every equation even though it balances out. But practical reasons don't dismiss the accuracy of using such a model.
technically thats impossible. but as the op/einstein pointed out, because of relativity the sun could be said to revolve around the earth. they can't both revolve around each other simutaniously.
I guess it depends what you mean by simultaneously. In a sense, they do, in another sense, they can't.
They do do it simultaneously if you're allowed to consider both frames of reference simultaneously. If you only consider one frame of reference, then it's an impossibility. So it depends on what you mean by simultaneously, since in mathematical models, there's no concept of time. They're two different models that can't be combined, but they're both accurate models.
They are both revolving around each other actually. However the sun is moving in a much slower and almost unnoticeable rate since earth's mass is negligible w.r.t the sun.
You're talking about their revolution around the center of mass(where the sun is moving at a slower rate). The term "revolve around" deals with holding it's position as the center and seeing what travels around it. In that sense, the sun must spin around the earth at the same speed the earth spins around the sun.
agreed, have you read einsteins thoughts on where scientific thought comes from (off topic)? he's my favorite science/philosopher
I don't think I have. Any good references?

[wiggely]

I guess it depends what you mean by simultaneously. In a sense, they do, in another sense, they can't.
They do do it simultaneously if you're allowed to consider both frames of reference simultaneously. If you only consider one frame of reference, then it's an impossibility. So it depends on what you mean by simultaneously, since in mathematical models, there's no concept of time. They're two different models that can't be combined, but they're both accurate models
i love relativity. i agree with above.

I don't think I have. Any good references?
i'll look into it, but don't hold your breath (busy and such). keep your eye out though

[DaNuKA_SAN]

First of all all of these posts are immensely misleaded.

First problem? You're looking into the movement of celestial objects as if you were in the same euclidean reference point as if you were on earth. This is hardly the case. Newton's laws of motion work only within the set reference point that is a celestial bodies gravity well. Meaning, within close enough proximity to a celestial body, Newton's laws still apply within that reference frame, with the constant G set for the proper value. The precision is enough to tolerate the margin of error.

This brings us thus to our second point, Einstein's laws of general relativity. On a larger scale this is were we look at the interaction between celestial bodies due to this one single property. The mass of the objects in question is SO massive, that it has a noticeable effect on space-time itself.

Think of it as dropping an ant and a fist sized rock into a pool of water. The ant has a negligible if not almost inexistent effect upon touching the waters surface, hardly breaking the water tension. The same could not be said for the rock.

While the analogy doesn't reflect the underlying mathematics, it does give you an idea of the scale of things we are looking at.

[Dionysus]

You did it again, Danuka. :apathy I stated that the energy (and dynamics, but didn't use the word) only work properly in the correct frame. Yet here you are stating that I am misleaded.

I even used a crappy analogy to outline how simply looking at energy shows how the physics don't make sense in an arbitrary frame.

However, I do disagree with you on one point. I believe the kinematics can be represented in an arbitrary frame, assuming said kinematics are known before hand (working things out in the proper frame of reference). Now, this is exceedingly difficult and requires tranforming coordinates over various manifolds and various scary things. It's certainly not Euclidean, but certainly not impossible. (Until you factor in quantum mechanics.)

[Masa]

both the sun and the earth revolve around their combined center of gravity, which happens to lie within the sun because of its much greater mass. so saying the earth revolves around the sun isnt far from the truth. saying that the sun revolves around the earth, however, is not the case. it just makes the sun wobble a bit.

[Ucal]

I can see where you're going with the practical argument, but I'd rather people just say that the earth revolves around the sun to simplify things, since including the statement that the sun doesn't revolve around the earth isn't true. Omitting the truth is better than including a falsehood.

The discovery wasn't so much that the Sun doesn't revolve around the earth so much as the Earth isn't a universally fixed center of all things revolving in the universe.

Its just a matter of ease. Quantum physics technically makes it possible for you to turn into a giant cosmic planet eating rubber ducky named Zoltron, but you don't see scientists adding footnotes to their papers about it. Besides, any student who actually pays attention in physics class will realize what you're stating to be true, but the 6th graders who learn about Galileo and Christopher Columbus are not the people to get nit picky on details with.