Earth Sciences Forum

scpg02 · Joined: 22 Jul 2007 Posts: 221 Location: Sacramento

Scientists find elusive waves in sun's corona

Discovery can help unlock secrets of corona's heat, solar storms

NileQueen · Posted: Thu Sep 06, 2007 5:32 am Post subject:

Thanks for the news Maggie. It has been a mystery why the corona is so much hotter than the surface of the sun. Maybe they will find out the reason for that too.

sneez · Joined: 11 Aug 2007 Posts: 13

Which is funny quite interesting because thermodynamics says that heat can flow from hot to cold objects ONLY otherwise work must be done on the system to reverse the flow.

NileQueen · Posted: Fri Sep 07, 2007 8:01 pm Post subject:

Perhaps like ice worms on glaciers, there are solar maggots or something doing some work Razz

scpg02 · Joined: 22 Jul 2007 Posts: 221 Location: Sacramento

I heard somewhere that the corona is very loud. They were speculating that the sound is actually heating the corona.
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sneez · Joined: 11 Aug 2007 Posts: 13

There is evidence of sound waves propagating in the sun itself (bellow the photosphere) and sounds traveling outwards as well.

However there exists a relativelly dense plasma above the photosphere (the layer which is the black body approximated to 6000K). The so called corona.

If sound waves indeed heat this layer it does not explain why its trapped in the corona. And still the (thrmal) heat in that plasma (i suppose, im not plasma physicist) must go from hot to cold, hence it must heat the sun photosphere as well as the cold space. All articles I found on this totally ignore this fact that hot corona must heat the bellow photophsere. While its acknowladged as paradox, its not taken into account, as far as my knowledge goes, when accounting for how it evolved to be so.

Baywax · Joined: 23 Jul 2007 Posts: 113 Location: Pacific West Coast

The sun has been heating ever up since the industrial revolution started and we just better do something about it..... I'm cereal.... super cereal.

Shocked

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sneez · Joined: 11 Aug 2007 Posts: 13

Thought: On Earth the thermosphere is much hotter than surface. According to thermodynamics the heat should flow from hot to cold, hence aparent! pradox?

Well, given the low pressure of at thermospheric altitudes its hard to really think of it as tempereature in the same sense as at the surface. One thing to note, without the sun, earth's thermosphere would not have these high kinetic energy species which we interpret as temperature for convenience. It is the solar UV, and X-rays + particles in solar wind that ionize and highly excite the thermospheric region.

Sun's corona is also very tenuous, however, there is no external source to excite (kinetically) the particles as we move farther away from sun's "surface", and we would, therefore, expect that "temperature" of corona should by lower. I think the same explanation does not apply for sun as applies for earth. On the other hand I think the statement I made and which is usually made concerning this issue is wrong as well. There is no violation of heat flow from sun surface to the corona, the corona is for practical purposes much cooler. What I mean is given in the explanation of earth's thermosphere temperature.

Does this sound consistent?

(hence, there must be process that excites sun's corona region to high kinetic energies).