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The Sun, in Stereo

Denver

Penultimate Amazing
Denver
Joined
Sep 8, 2007
Messages
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First Ever STEREO Images of the Entire Sun

This was all cool. Or hot.
This part especially:

Consider the following: In the past, an active sunspot could emerge on the far side of the sun completely hidden from Earth. Then, the sun's rotation could turn that region toward our planet, spitting flares and clouds of plasma, with little warning.

"Not anymore," says Bill Murtagh, a senior forecaster at NOAA's Space Weather Prediction Center in Boulder, Colorado. "Farside active regions can no longer take us by surprise. Thanks to STEREO, we know they're coming."
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Denver said:

First Ever STEREO Images of the Entire Sun
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It is a cool research program. I remember reading up on it quite a while before it was launched back in '06. It was claimed at the time that it would prove once and for all, yes or no, whether the Sun has a solid or rigid iron surface. (More information on that zany idea in this moderated thread.) We had some discussion on it at the Skeptic Friends Network forum. A user there actually made a bet that the STEREO program would vindicate his crackpot claim about the Sun having a solid surface in this post at SFN from almost exactly 5 years ago. (Still waiting for the payoff on that bet.)
 
ugh. While I have no expertise that would allow me too disregard a solid solar model I am loath to read those links GeeMack.

Is there any chance that the new STEREO data will change peoples opinions regarding a solid solar surface?
 
Humanzee said:
ugh. While I have no expertise that would allow me too disregard a solid solar model I am loath to read those links GeeMack.

Is there any chance that the new STEREO data will change peoples opinions regarding a solid solar surface?
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No. On that issue it won't change the position of the thousands of legitimate solar scientists and astrophysicists, if only because the satellites aren't equipped to see anything below the photosphere where the solid surface allegedly exists. Nothing other than helioseismology can "see" below the photosphere because by definition it's where the Sun's atmosphere becomes opaque.

And it won't change the minds of the two or three crackpots who believe the Sun has a solid surface because for them it's a point of faith. No legitimate science and no quantitative objective evidence brought them to their belief, and none will sway them from it.

But, the STEREO program does offer a lot of possibilities to study the Sun's activity from the photosphere outward. We'll be able to watch solar storms from their formation. We'll be able to see the physical growth of coronal mass ejections from their inception instead of waiting until they come around to our side. There won't really be a far side of the Sun now, since the two satellites will allow us to observe virtually the entire surface at once.
 
Sorry if I'm a little slow, but this is just the first time we have seen "both sides" at once right? If you listen to this 25 second video, in some parts, it sounds like he is saying this is the first time we have seen the "far side" of the Sun. I know the moon really does have a far side that never faces us, but the Sun is not the same way is it?

http://www.bing.com/videos/watch/video/nasa-pics-here-comes-the-sun/6a6sxax
 
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More like the first time we've seen both hemispheres at the same time. ;) The sun does spin on an axis too.
 
Checkmite said:
Is it just me, or does the alleged image of the "far side" of the sun look uncannily identical to the near side? Can't wait to see how "scientists" spin that one. I call conspiracy.
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I think that NASA faked the solar landing.
 
A youtube uploaded two days ago

Seeing the whole sun front and back simultaneously will enable significant advances in space weather forecasting for Earth, and improve planning for future robotic or crewed spacecraft missions throughout the solar system.

These views are the result of observations by NASA's two Solar TErrestrial Relations Observatory (STEREO) spacecraft. The duo are on diametrically opposite sides of the sun, 180 degrees apart. One is ahead of Earth in its orbit, the other trailing behind.

Launched in October 2006, STEREO traces the flow of energy and matter from the sun to Earth. It also provides unique and revolutionary views of the sun-Earth system. The mission observed the sun in 3-D for the first time in 2007. In 2009, the twin spacecraft revealed the 3-D structure of coronal mass ejections which are violent eruptions of matter from the sun that can disrupt communications, navigation, satellites and power grids on Earth.
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When one satellite is on the far side of the sun (relative to Earth and the other Sat), how does it transmit what it is seeing to Earth? Isn't it blocked by the sun?

ETA: Unless my mental model is wrong, and the satellites aren't line up that way, but rather one is on the 'right' side and one is on the 'left' side, relative to Earth. Which makes the term 'far side' even more inaccurate.
 
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Denver said:
When one satellite is on the far side of the sun (relative to Earth and the other Sat), how does it transmit what it is seeing to Earth? Isn't it blocked by the sun?

ETA: Unless my mental model is wrong, and the satellites aren't line up that way, but rather one is on the 'right' side and one is on the 'left' side, relative to Earth. Which makes the term 'far side' even more inaccurate.
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The configuration is a triangle with the two satellites and the Earth making the three points and the Sun in the center.
 
Denver said:
Unless my mental model is wrong, and the satellites aren't line up that way, but rather one is on the 'right' side and one is on the 'left' side, relative to Earth. Which makes the term 'far side' even more inaccurate.
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Except that they're both far enough off to the right/left side for each one to see half of the sun's near (to Earth) side and half of its far (from Earth) side. Over the next few years, the region of overlap on the far side where both satellites can actually see the same bit of it will grow wider and wider, and they'll lose some of their view from the near side. But that's OK because we can already see the near side from here, so the three views (from both satellites and Earth) will ensure complete coverage for years to come, just with shifting overlap zones.

There will come a time when they'll both be completely opposite the sun from us and unable to transmit their data to us directly. It will be brief, though, because the area of space that the sun hides from our view at any given time isn't very wide. (Put a volleyball on the ground, walk about 80 feet away from it, and look back. How wide is the area on the ground 160 away from you that the volleyball blocks your view of?) It would be possible to still get the data live if there's another satellite ahead of or behind one of them that can relay it to us, or we could get it with a delay if they can record it and then dump their recordings on us once they're back in contact, but I don't know whether either of those is the case. If not, then we'll just lose contact for a while and wait to regain it.
 
GeeMack said:
The configuration is a triangle with the two satellites and the Earth making the three points and the Sun in the center.
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The two satellites are 180o apart, relative to the sun, so the sun must lie on one edge of the triangle not in the centre.
This seems an like an inherently unstable position, i.e not L4 or L5 for example, have I got that correct?
 
It's not stable and not intended to be. They are proceeding along almost the same orbit as Earth at slightly different speeds, so the differences in speed will continue to change the shape of the triangle traced between them and the Earth.

For the next few years, they'll get farther from the Earth and closer to each other. The triangle has been obtuse until now (with the sun outside it), is just about now becoming right (with the sun in the middle of one edge), and will soon be increasingly acute (with the sun inside it and creeping closer to its center). The most ideal position might be an equilateral triangle with the sun at its center, and the satellites will get there, but unless they still have engines and fuel to navigate with, they'll just keep on going, making the triangle skinnier and skinner until they pass right by each other on the opposite side of the sun from us. Then the triangle will start getting wider again as they start getting farther apart from each other and closer to us. Eventually they'll be back to the equivalent position to the one they're in now, a right triangle with the sun in one edge, and then keep going, forming an increasingly obtuse triangle with the sun outside it. At that point, we won't see the entire far side of the sun anymore, but that will be after years of data collection when we could. Eventually they'll come back to pretty close to the Earth as the faster one catches up with us and we catch up with the slower one, and Earth's gravity will either pull them down or slingshot them away.
 
sphenisc said:
The two satellites are 180o apart, relative to the sun, so the sun must lie on one edge of the triangle not in the centre.
This seems an like an inherently unstable position, i.e not L4 or L5 for example, have I got that correct?
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Like this...

stereo1.jpg


Delvo said:
For the next few years, they'll get farther from the Earth and closer to each other. The triangle has been obtuse until now (with the sun outside it), is just about now becoming right (with the sun in the middle of one edge), and will soon be increasingly acute (with the sun inside it and creeping closer to its center).
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Yes.
 
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Delvo said:
It's not stable and not intended to be. They are proceeding along almost the same orbit as Earth at slightly different speeds, so the differences in speed will continue to change the shape of the triangle traced between them and the Earth.
....
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Thanks Delvo, that makes sense.
 
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