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suntrack2
2007-Sep-27, 12:48 PM
is the sun's surface doing "up and down like movements daily", or this is not true ? just an action like breathing in and breathing out. or the up and down of the surface movement can only be seen in "helio seismic activities" ?

hhEb09'1
2007-Sep-27, 03:04 PM
At what level of measurement is your question directed? Do you mean at the angstrom level, the centimeter level, the kilometer level, or the thousand kilometer level? Or greater? If the average radius was changing up and down by a couple angnstroms, would that be a positive answer to your question?

And when you say daily, do you mean an earth day, a solar day (whatever that is), or just a periodic process in general?

jlhredshift
2007-Sep-27, 03:14 PM
is the sun's surface doing "up and down like movements daily", or this is not true ? just an action like breathing in and breathing out. or the up and down of the surface movement can only be seen in "helio seismic activities" ?

If the diameter of the Sun changed by one mile the circumference would only change by 3.1459 miles. Scale up as needed. It is hard to measure the edge of plasma.

hhEb09'1
2007-Sep-27, 03:21 PM
If the diameter of the Sun changed by one mile the circumference would only change by 3.1459 miles. It's better to go with 3.14 in this case :)

jlhredshift
2007-Sep-27, 03:22 PM
It's better to go with 3.14 in this case :)

I hate when I forget a 1.:)

suntrack2
2007-Sep-27, 05:01 PM
At what level of measurement is your question directed? Do you mean at the angstrom level, the centimeter level, the kilometer level, or the thousand kilometer level? Or greater? If the average radius was changing up and down by a couple angnstroms, would that be a positive answer to your question?

And when you say daily, do you mean an earth day, a solar day (whatever that is), or just a periodic process in general?

say, periodic process in general and at greater level !

aurora
2007-Sep-27, 05:56 PM
I remember seeing a "sun quake" image recently, where there were rings spreading out from the center of an explosion. maybe search on APOD for it?

John Mendenhall
2007-Sep-27, 06:47 PM
Here:

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

rtomes
2007-Sep-28, 10:46 AM
is the sun's surface doing "up and down like movements daily", or this is not true ? just an action like breathing in and breathing out. or the up and down of the surface movement can only be seen in "helio seismic activities" ?
Recently the sun's radius was found to vary over the solar cycle by a very small amount. But that takes 11 years.

There are a series of oscillations that have periods in the range about 3 to 11 minutes, mostly around 5 to 6 minutes. These have patterns like a checkerboard with various numbers of alternating up and down zones. They result from sound waves bouncing around in the sun. See http://en.wikipedia.org/wiki/Helioseismology