Why does the sun travel faster about its equator?

[Ian_Brooks]

Would this be valid for all other planets as well?

 

[xxChrisxx]

Angular velocity depends on radius (distance from axis of rotation) so i'll say yes.

 

[Ian_Brooks]

Hmmm - so if we considered the the sun moving (rotating) with constant speed, then in the xy plane a point about the equator would have to cover more distance than at the poles. Therefore the point about the equator would be traveling faster than at the poles to maintain the same speed.

ahh that makes more sense. Thanks

 

[xxChrisxx]

Yes, and the equator is further away from the axis of rotation that other parts. Ignore the word radius in my previous post, the bit in the brackets is all that matters.

 

[Ian_Brooks]

thanks

 

[Borek]

Angular velocity depends on radius (distance from axis of rotation) so i'll say yes.

Completely off. Linear velocity depends on the distance from axis, angular velocity should be constant.

And in the case of Sun there is an anomaly - angular speed at the equator is higher than the speed at other lattitudes. No idea why, but it is an observable fact. Equator rotates in 25 days, rotation at 75 deg lattitude takes 36 days.

 

[Ian_Brooks]

this is what I came across on a documentary about fusion energy and the sun. So my reasoning above is way off then?

Where could I look for proposed theories describing why the sun undergoes this anomaly.

After watching the documentary last night I kept thinking to myself
"if all bodies move at a constant velocity how can points on the equator travel faster"

That was the best I could come up with above.

 

[Ian_Brooks]

ok this is what I'm having troubles understanding

All matter in the Sun is in the form of gas and plasma because of its high temperatures.
This makes it possible for the Sun to rotate faster at its equator (about 25 days) than it does at higher latitudes (about 35 days near its poles).

So do all bodies of plasma display this phenomena?The differential rotation of the Sun's latitudes causes its magnetic field lines to become twisted together over time, causing magnetic field loops to erupt from the Sun's surface and trigger the formation of the Sun's dramatic sunspots and solar prominences (see magnetic reconnection).

This is essentially why I posted this question - the non uniform magnetic fields of the sun cause sun spots
- higher temp,
- mag field suppresses plasma
- solar flare/solar corona yada yada
yet they come and go - why?



This twisting action gives rise to the solar dynamo and an 11-year solar cycle of magnetic activity as the Sun's magnetic field reverses itself about every 11 years.

The influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium creates the heliospheric current sheet, which separates regions with magnetic fields pointing in different directions. The plasma in the interplanetary medium is also responsible for the strength of the Sun's magnetic field at the orbit of the Earth. If space were a vacuum, then the Sun's 10-4 tesla magnetic dipole field would reduce with the cube of the distance to about 10-11 tesla. But satellite observations show that it is about 100 times greater at around 10-9 tesla. The dipole field of the sun is roughly the same as the Earth's magnetic field, but it extends over a vastly greater volume of space. Magnetohydrodynamic (MHD) theory predicts that the motion of a conducting fluid (such as the interplanetary medium) in a magnetic field induces electric currents, which in turn generate magnetic fields, and in this respect it behaves like an MHD dynamo.

I posted this here thinking it was something fundamental that I should have known - thus saving myself from embarrassment at the hands of the astrophysics subsection.
- but I guess it would be better if the thread was now moved there

The question i wanted to lead up to wasI wanted to find out how the sun maintains the same over all temperture when we have the variability of sun spot occurrence and solar flares hurling mass and energy out of the body of the sun.

What am i missing?

 

[xxChrisxx]

Completely off. Linear velocity depends on the distance from axis, angular velocity should be constant.

And in the case of Sun there is an anomaly - angular speed at the equator is higher than the speed at other lattitudes. No idea why, but it is an observable fact. Equator rotates in 25 days, rotation at 75 deg lattitude takes 36 days.

Well all I've got to say is... oops. I did acutally mean tangential velocity, I'm going to blame the fact that it was late and/or I am in idiot on the error.

It's clear that the op's question is going beyond the simple rotation of a sphere, so i'll bow out for now as I know bugger all about the sun. I'll try asking my brother who looked at something similar to the OP's second question in his dissertation.

 

[Borek]

oops

Happens to everyone

 

[Chronos]

The temperature across the sun's surface is not uniform. See http://xrt.cfa.harvard.edu/resources/pubs/narukagetextfigs.pdf