Jupiter's Orbital Velocity & Equatorial Velocity cancel?

[Neddy Bate]

Are not both velocities, orbital and rotational nearly equal , within 3 % of 13 km/sec?
The same with Saturn at ~ 10 km/sec?

Yes they are, but that does not make the centrifugal forces cancel out. Those are speeds as would be measured by a speedometer placed on the truck, and on the edge of the carousel. If the carousel's diameter is much smaller than the truck's race track diameter, then in order for the centrifugal forces to cancel out as you seem to think, the speeds would have to be vastly different, not the same.

Consider driving a car at a speed of 30 around a small circle, versus driving a car at a speed of 30 around a larger circle. Which one makes you feel more of an attraction to the side of the vehicle?

 

[nebel]

Yes they are, but that does not make the centrifugal forces cancel out.

That is correct. but both centrifugal forces work in opposing directions. If they do not cancel out at the point of contact, where the lady passes the energy drink to her daughter, on the chair, the pony, where there is zero velocity difference, then it would be cancelled out at a different points in latitude, or time of day, or inward toward the centre of rotation.
I found remarkable that these 2 great planetary masses have their Orbital and Rotational velocities so closely matched, and while that does not mean forces match too. These are unique situations , implications we might not have full insight to yet.

 

[nebel]

You are completely and utterly incorrect. Kinetics does not predict this, nor does any real world example work in this way.

Strong words that. I dare you then to take this example, (which is a reworking of your original model) and refute the actions, step by step.
1) vehicle on circular track , prograde travel, all pendulums swing to the outside. the right.
2) pendulum carrier made to rotate in prograde direction, causing the pendulums to lift out from their centre of rotation.
3) when vehicle and carrier speed match, pendulums swing out more on the outside, less on the left, inside and near their inside widest swing, pendulums hover motionless for a moment over the ground. That "zero velocity" point in time is reached slowly, starting in the forward facing, and ending slowly toward the rear of the moving vehicle.
4) If you want to match the 2 opposing centrifugal forces, ( have the moving pendulums on the inside perfectly plumb), either adjust the carrier speed, or adjust the radius of the pendulums suspension points.
Since in the case of Jupiter and Saturn you have matching speed, big track radius, but fast rotation, 10 hour days, you have wide swing pendulums, aka oblateness, but only small energy tides, that is every 5 hr. increased lifting at equator noon and midnight,- compared to poles and leading and trailing normal levels.
.

 

[nebel]

I am really sorry if I had anything to do with people addressing this crank. He just craves attention and is beyond redemption. I have no idea why he is permitted to post his junk in the science section.

Your frustration is understandable, but don't forget, just as an exercise, serious contests have been waged over smaller deviations,-- in the precession data of the Mercury orbit.

 

[Neddy Bate]

You are still neglecting that the average distance between Jupiter and the Sun is 779,000,000 km whereas the radius of Jupiter itself is 69,911 km. So one circle radius is approximately 10,000 times larger than the other.

Imagine a car driving on an enormous circular racetrack at some fixed speed, S. The size of the circle is so large that it is almost like driving in a straight line. The passengers barely feel any centrifugal force pulling them to the side.

Now imagine a small carousel 1/10,0000 the size of the race track, and let it have the same speed as the car, S. The riders on the carousel feel plenty of centrifugal force pulling them to the side.

In this case, letting the car tow the carousel around the track will not result in the cancellation of centrifugal forces that we talked about earlier with the truck, because back then I had started with the stipulation that both impart 1 "gee" of centrifugal force, because I wanted to show that the forces can cancel under certain circumstances. But this time I started with the stipulation that they have the same speed, but vastly different diameter circles, so the centrifugal forces do not cancel. This is what you are talking about with Jupiter, two vastly different circle radii but the same speed.

But note that a mother standing on the correct side of the racetrack could theoretically hand her child a candy bar for one instant of time where there is zero relative speed between the two. Yet the child could still fly off the carousel if he does not keep a firm grip on the horse's neck.

 

[nebel]

But note that a mother standing on the correct side of the racetrack could theoretically hand her child a candy bar for one instant of time where there is zero relative speed between the two. Yet the child could still fly off the carousel if he does not keep a firm grip on the horse's neck.

I think I have dealt with your valid observation about the real, disproportional planetary values in previous posts. ( like a 1/2 inch energy tide* raised on Jupiter)
Yes, and I might have forgotten to mention that the kids would have to hang on, particularly on the outside part of their rotation; yet I showed, in the above post, how the g forces could be tuned to perfectly balance, have a pendulum on the carousel point to the centre of the earth at noon.
In another situation, a balloonist floating in Jupiter's clouds would not be exempt form all the rotational, gravitational forces at noon, but she could pluck a daisy from an imaginary lawn that stretched around the orbit, at noon.
So am I correct in saying that on Jupiter and Saturn the differences in g forces are small, but real, but the cancelling of velocities is total?
*tides were considered in water. in a cloud environment one could see higher values, (see thermal tide in the Yarkovsky effect )

 

[Neddy Bate]

I think I was writing my post #85 as you were posting #83 so I didn't see that post until later. If I understand you correctly, you do acknowledge now that the centrifugal forces do not cancel in the case where the speeds are the same but the radii are vastly different. Correct?

 

[billvon]

Strong words that. I dare you then to take this example, (which is a reworking of your original model) and refute the actions, step by step.
1) vehicle on circular track , prograde travel, all pendulums swing to the outside. the right.
2) pendulum carrier made to rotate in prograde direction, causing the pendulums to lift out from their centre of rotation.

Where is the "carrier?" Is this a spinning object on the ground, similar to a carousel? If so, OK.

3) when vehicle and carrier speed match, pendulums swing out more on the outside, less on the left, inside and near their inside widest swing, pendulums hover motionless for a moment over the ground. That "zero velocity" point in time is reached slowly, starting in the forward facing, and ending slowly toward the rear of the moving vehicle.

Nope. Both experience centrifugal force. Both result in pendulums swinging out. The pendulums on the carousel do not "know" what the truck is doing.

4) If you want to match the 2 opposing centrifugal forces, ( have the moving pendulums on the inside perfectly plumb), either adjust the carrier speed, or adjust the radius of the pendulums suspension points.

In no case will you have the pendulums "perfectly plumb."

 

[nebel]

The carrier of the pendulums, is the carousel on the truck, vehicle.

Where is the "carrier?" Is this a spinning object on the ground, similar to a carousel? If so, OK.

Nope. Both experience centrifugal force. Both result in pendulums swinging out. The pendulums on the carousel do not "know" what the truck is doing.

The pendulums on the carousel know what the truck is doing, they all swung out to the right, when they were not revolving, and the truck started moving. Free particles act on all forces simultaneously.

In no case will you have the pendulums "perfectly plumb."

Install a sliding track for one of the pendulums, radially, in which you can move, and fix, the pivot of the pendulum (or the position of the horsy) selectively from centre -- to the periphery. At the moment when that hardware's direction faces toward the centre of the circle road, (noon on the planets, the Sun), The pendulum, when fixed
in the centre position,--- the truck speed beeing dominant (no rotational movement like on the poles), the pendulum will swing to the right, the outside of the circle road.
On the perimeter position, (where the swing seats would be mounted), the rotation's centrifugal force will dominate, the pendulum will swing max to the left, the inside. out from the carousel, but in toward the centre of the road. Now:
between these two extreme swings is a middle ground on the radial suspension track. At some point the pendulum will neither swing out nor in, fix it there: because the two opposing centrifugal forces are balanced*, the pendulum points to the centre of the earth at "noon"; -- Then it will resume it's swing out, until the velocities adds up at "midnight".
location, location , and timing, does it every time, not only in real estate.
* you can play with other variables, the curvatures, velocities, but the is always a point in time and space available where the forces balance, the pendulum is plumb. ( from lead in latin)

PS I am trying to pinpoint a line, where imaginary circus artists could transfer from trapezes during zero velocity inter-planetary situations. could you guess where?

 

[billvon]

The carrier of the pendulums, is the carousel on the truck, vehicle.

OK. In that case -

If you have a truck going around a FLAT track, then you will indeed see an effect on the pendulums - they will all have a bias towards the acceleration. (To the "out" side if you are turning, to the back if you are accelerating, to the front if you are braking.)

If you have a truck going around a BANKED track, such that the acceleration adds directly to gravity, you will see no bias in the pendulums in any direction. (You may see an overall reduction in deflection if the resulting downward acceleration increases significantly.)

If you have a truck going around an OVERBANKED track, such that the acceleration tends to push objects towards the "down" side of the truck, you will get the opposite bias that you got from the flat track. (i.e. bias towards the "in" side.)

So no effect from the turning of the truck - but a significant effect from the acceleration that the truck is experiencing.

Same thing with Jupiter. If Jupiter was on a long rope connected to the Sun and was being spun around, then you'd see an effect on the atmosphere from the acceleration caused by the rope. But if it is orbit (i.e. in freefall) you will not.

The pendulums on the carousel know what the truck is doing, they all swung out to the right, when they were not revolving, and the truck started moving. Free particles act on all forces simultaneously.

Or they don't swing at all - or they swing to the left. Depending on the bank of the track.

location, location , and timing, does it every time, not only in real estate.

I'd go with physics and math. And both agree - the turning of the truck doesn't matter. Only the acceleration does.

 

[nebel]

Or they don't swing at all - or they swing to the left. Depending on the bank of the track.

This is not the Daytona 500, or the brick yard Indianapolis., or done "en miniature" on a motorcycle driving on level curving roads. or in an aeroplane, flying a holding pattern.

 

[nebel]

I think I was writing my post #85 as you were posting #83 so I didn't see that post until later. If I understand you correctly, you do acknowledge now that the centrifugal forces do not cancel in the case where the speeds are the same but the radii are vastly different. Correct?

Referring you to post# 42, I do not recall having stated that the centrifugal forces cancels for planets. only the velocities do, for the two. My last posts, gratefully prompted by billvon, should clear up any misconception on that. Thank you for pointing out the real ratios.
It does not not mean there are no effects though. more to come on that, hopefully.

 

[Neddy Bate]

If you have a truck going around a FLAT track...

In all of the scenarios I was describing in this thread, I had been assuming the vehicle was on a flat track, and that the towed carousel was also flat. The apparent (centrifugal) forces can momentarily cancel, in cases where they happen to be equal and opposite. But this does not automatically occur whenever the speeds are equal and opposite. The two radii must be considered also. That is the one thing I was trying to see if nebel agreed with, and it seems that he does agree in post #92.

 

[nebel]

The apparent (centrifugal) forces can momentarily cancel,

I just want to add, that the possible cancellation, like in the "plumb" position in post #89, the approaching of that condition, is not a sudden unexpected shock, but is a scenario that starts building for a quarter of a revolution and fades slowly back after a 180 degrees development. and
The centrifugal cancellation happens on an imagined simulation track, not the planets! to keep a straight track record.

 

[Neddy Bate]

Referring you to post# 42, I do not recall having stated that the centrifugal forces cancels for planets. only the velocities do, for the two.

I think it was this line from post #59 where you seemed to be saying it:

Zero orbital velocity means zero centrifugal force, at that moment on that particle, maximum solar pull.

So, in retrospect, I guess you were just pointing out that the centrifugal force which arises from the planet orbiting the sun is zero at noon, while the centrifugal force which arises from the planet rotating on its axis is still there.

I'm not sure what the significance of this is. The centrifugal force which arises from Jupiter rotating is significant enough to create its oblate shape, bulging all the way around the equator. But I imagine the centrifugal force which arises from the planet orbiting the sun is very small, maybe even smaller by a factor of 1/10,000. So at noon on the equator, we don't see a lump or a pimple sticking out. It might be there but too small to notice.

 

[billvon]

This is not the Daytona 500, or the brick yard Indianapolis., or done "en miniature" on a motorcycle driving on level curving roads. or in an aeroplane, flying a holding pattern.

Exactly. Because in those cases you get a different result.

If you accelerate the carousel on the truck, that force adds to the centrifugal forces in some places, subtracts in others.

If you turn truck while carrying the carousel, it matters not at all - provided there is no acceleration from that turn.

It is the acceleration, not the turning, that matters.

 

[nebel]

So at noon on the equator, we don't see a lump or a pimple sticking out. It might be there but too small to notice.

Yes, the effect is small. I opined 1/2 an inch ( in post #66). It would not even show up as lump or a pimple, but an additional tidal component, that starts rising at sunup and settle back fully at sundown.

 

[nebel]

Counterrotating objects are certainly not more stable. Indeed they are LESS stable than the equivalent spinning mass. Spinning masses have a gyroscopic moment which tends to stabilize them in at least one plane; counterrotating masses do not.

the gyroscopic effect has the annoying tendency to produce a 90 degrees deflection, and then there is torque. Having counterrotating units cancels that effect effectively.
The illustration of a truck carrying a carousel was a good one. Driving it on a straight road, a banked road (or loading it into an Antonov) will eliminate the simulated effects of the planetary orbits.
keeping it simply, occam shaved:
prograde orbits, rotations will add forces on the outside, subtract them on the inside.

 

[nebel]

The comparison to a tire on a snowy road is just silly.

The tire being stationary on the road contact while the vehicle is speeding, is not as silly as you make out. One of my implied questions in the OP was how that zero orbital velocity would affect interactions.
In the case of the non- speeding tires on contact, -- it causes them to pick up gravel in their grooves. Absorption is maximized at planetary noons. It is holding still for a portrait too. and
at double the orbital velocity in the fender, perhaps some of the dirt gets dislodged. Jupiter's equator clouds, at midnight position, travelling at twice the orbital speed, hit a pace that is normally seen only in asteroids, ~ half the distance to the sun.

 

[origin]

I am really getting fed up with idiotic posts clogging up the science section.