Re: Solar Activity Report for 8/4/04
- WOW that is so cool. Thats like telling where an island is on the
other side of a planet just from water waves.
loud it would be if the sound could get out!
> Date: Fri, 06 Aug 2004 12:00:28 -0000
> From: "David" <b1blancer1@...>
>Subject: Re: Solar Activity Report for 8/4/04
>--- In firstname.lastname@example.org, "XK SAZ" <swezlex1@y...> wrote:
>> How do you tell it is holding together on the back side of the sun??
>I just look at the SOHO satellite images on SPACEWEATHER.COM! Ohh,
>I'll bet you meant how can anybody tell, didn't you? ;-)
>The Solar and Heliospheric Observatory (SOHO) spacecraft has an
>instrument on board called the Michelson-Doppler Imager (MDI). The
>MDI can detect movements in the "surface" of the sun. Now obviously,
>the sun doesn't have a solid surface. When I say "surface," I really
>mean what we see as the visible surface, or the photosphere. Hold
>Did you know the sun makes noise? It does. The sun is a vibrating
>ball of sound waves. It isn't sound you could hear, though. The
>sound waves that travel though the sun have a period of around 5
>minutes. The sound we humans hear have a period much, much shorter
>than that. Still, though, it is sound, albeit it as very low
>frequency. Enter the field of study known as helioseismology. In
>much the same way that terrestrial scientists use the vibrations of
>earthquakes to probe the Earth's interior, solar scientists can do the
>same thing for the sun.
>Now obviously, you can't put any detection equipment on the sun, so
>how do they do that? By analyzing the movements in the photospere
>that the sound waves cause. Remember the MDI?
>Now for the sunspot part. It is known that intense magnetic fields on
>the sun, such as those associated with sunspots, cause variations in
>the way that sound waves travel through the sun. By analyzing
>photosphere movements with SOHO's MDI instrument, scientists can tell
>where the intense magnetic fields are on the other side of the sun.
>Where you find strong magnetic fields, you'll find sunspots.
>The technology isn't perfect, but it does a pretty good job of
>detecting large sunspots with strong magnetic fields. See this link
>for more info : http://www.spaceweather.com/glossary/farside.html