Heliopolis

Palomar · 2003-12-12 12:23:17

*This thread is established for discussion of our Sun.

I received _The Cambridge Encyclopedia of the Sun_ by Kenneth R. Lang via UPS 2 days ago. I discussed ordering this book at a different thread.

I'll summarize in my own words (-not- quoting) a brief bit of info about sunquakes. They are produced when a particularly powerful explosion or flare sends shock waves into underlying gases. On July 9, 1996 SOHO captured an image of concentric rings on the sun's surface resulting from a very large flare; these rings spread across a distance of 10 Earth diameters in just an hour. It also made the sun quake with an intensity equal to 40,000 times the energy released in the 1906 San Francisco earthquake.

Wow. Am I loving this book or what!??!

--Cindy :laugh:

Palomar · 2003-12-12 13:24:04

Those "little" photospheric granules

*3rd photo from the top...each approximately 1000 kilometers in diameter. Yipes.

***

Here's a bit more interesting info I read in _The Cambridge Encyclopedia of the Sun_: Our Sun rings like a bell.

About sound waves: Summarizing in my own words, the book says sound waves traveling deep into the Sun move nearly perpendicular to the photosphere when the sound waves hit it -- which causes the entire Sun to ring like a bell.

Here's an amusing anecdote (and direct quote): "Those with shorter trajectories strike the photosphere at a glancing angle, and travel through shallower and cooler layers. Sounds with both deep and shallow turning points go around and around within cavities inside the sun, like hamsters caught in an exercise wheel."

The text goes on to say that all the notes sounding within the Sun, combined, have been compared to a resonating gong in a sandstorm -- all making an "incredible din." But the Sun makes order out of this chaos by reinforcing particular notes resonating inside it, like plucked guitar strings.

Does anyone know where a person might be able to download and listen to Sun sounds on the internet? I'll be looking for this myself...please share if you have info before I'm able (if at all) to find any.

--Cindy

Palomar · 2003-12-12 13:49:53

I'll summarize in my own words (-not- quoting) a brief bit of info about sunquakes. They are produced when a particularly powerful explosion or flare sends shock waves into underlying gases. On July 9, 1996 SOHO captured an image of concentric rings on the sun's surface, resulting from a very large flare; these rings spread across a distance of 10 Earth diameters in just an hour. It also made the sun quake with an intensity equal to 40,000 times the energy released in the 1906 San Francisco earthquake.

Click Me

*In searching for sound files on the 'net, I found the link above. It includes 4 photos of the concentric rings I mentioned in my first post (resulting from a huge solar flare in 1996).

At the bottom of the web page you can listen to 2 sound files of the Sun's "heart beat" (I've listened to both). There is also a short movie clip, but I can't get it to work yet.

--Cindy

Palomar · 2003-12-13 07:54:43

Thomas Harriot, 1610

*The first person known to have recorded sunspots!

I first encountered his name while preparing a post pertaining to an 18th century telescope builder, for my Yahoo! group. I have been searching for quite a while to discover how he observed the sun; I thought perhaps he created his own filter somehow, or thought to project the sun's image through his instrument. The bottom of the web page tells how he managed this feat. Which reminds me of the sunspot my husband and I saw last month (Jupiter-sized, #488), during a sand and dust storm in our area.

--Cindy

Palomar · 2003-12-17 07:41:03

"Sun-Earth Connection"

*I found this link at the Astropix feature for December 17. I'm not sure I've ever seen this nice and informative web site before.

From the Goddard Space Flight Center.

The flare on the sun in the photo looks like a handle, as if the sun is all ready for something to come along, scoop it up and carry it away...

--Cindy

clark · 2003-12-17 14:39:00

Since this is about the Sun....

Stradivarius' sound 'due to Sun'

http://news.bbc.co.uk/2/hi/science/nature/3323259.stm

Reduced solar activity in the 17th Century may be the reason for the perfect sound of Stradivarius violins.
Scientists from Columbia and Tennessee universities in the US say the Sun's declining output at that time resulted in colder winters and cooler summers.
This produced slower tree growth which in turn led to denser wood with superior acoustical properties - circumstances not repeated since.
Today, musicians and collectors will pay many thousands for a Stradivarius.

Writing in the journal Dendrochronologia Lloyd Burckle, of Columbia University, and Henri Grissino-Mayer, of the University of Tennessee, say that the long winters and cool summers of the period produced wood that gave the unique, rich sound of the Cremonese instruments.
They point out that violin makers have always known that the selection of the wood makes all the difference to the sound of the instrument. Maple is preferred for the back, ribs, and neck, while spruce is preferred for the top.
Stradivari and other eminent Italian violin makers of the 17th and early 18th Century who worked in Cremona probably used the nearby forests of the southern Italian Alps as their source of spruce wood.
It seems that the trees growing during the lifetime of Stradivari experienced a unique set of environmental conditions that has not occurred since.

Aparently, some music is crafted by the stars themselves.

Palomar · 2003-12-19 09:52:09

*At spaceweather.com, you can keep track of the daily sunspot count. The web site is updated daily, and archived.

http://www.spaceweather.com

Yesterday's sunspot count was 92 (December 18). I was surprised to see today's number has jumped to 114 (December 19).

I'm rather sure I've not known before that the number of sunspots could rise so quickly in such a short amount of time. Wow.

I'll be watching it daily, to see if it's common for the number of sunspots to change like this.

--Cindy

Palomar · 2003-12-21 20:26:15

Sol as seen from Mars

*The 2nd image from the top:

"(The Sun in this 30 x 30 pixel image appears 38% smaller in diameter than it does from Earth.)"

I lost a book of mine (_Stars_ by Golden Press) with this information in it...finally Googled and found this. I'm hoping to recover that book...it has a chart showing the size of our sun as would be seen from each planet.

--Cindy

Shaun Barrett · 2003-12-21 21:18:49

I've always wondered what it would be like, Cindy, to stand on Mars and realise how much smaller the Sun looks.
I think that difference, plus the closer horizon and the lesser gravity, are the things which have always made me yearn to go to Mars. (And I use the term 'yearn' without exaggeration - it's the damnedest feeling to want something so strongly without really knowing quite why! There must be something mystical about that planet.)
As I've said before, I imagine a time when we can walk unprotected on the surface of a Mars transformed into a new home. I can almost feel the cool sea breezes and the salt spray of a sandy beach beside the northern ocean and I can feel the muted warmth of a smaller gentler Sun with its softer light.

It's been a while since I've pictured that scene.
Thanks, Cindy, for jogging my imagination back into gear!

Palomar · 2004-01-03 07:08:13

I've always wondered what it would be like, Cindy, to stand on Mars and realise how much smaller the Sun looks.
I think that difference, plus the closer horizon and the lesser gravity, are the things which have always made me yearn to go to Mars. (And I use the term 'yearn' without exaggeration - it's the damnedest feeling to want something so strongly without really knowing quite why! There must be something mystical about that planet.)
As I've said before, I imagine a time when we can walk unprotected on the surface of a Mars transformed into a new home. I can almost feel the cool sea breezes and the salt spray of a sandy beach beside the northern ocean and I can feel the muted warmth of a smaller gentler Sun with its softer light.
It's been a while since I've pictured that scene.
Thanks, Cindy, for jogging my imagination back into gear!

Photo by Bruno Nolf of Belgium

*Shaun: Keep talking like that and you might persuade me to become a Green. :;):

The photo in the link above is of Sunspot #536 over the eastern "limb" of the sun. It could cause "M-Class" solar flares. There's information at spaceweather.com (where I picked up this photo) about solar flare classification.

Really nice amateur astronomer pic.

--Cindy

Byron · 2004-01-03 07:17:49

*Shaun: Keep talking like that and you might persuade me to become a Green.

It's this kind of talk that made me a "Green" to start with...lol. I've also had the yearning to to run freely in the low Martian gee and playing in low-gravity surf of a Martian ocean...provided the climate is hospitable enough to do so...!

B

Palomar · 2004-01-04 08:51:14

*As nothing stays in my signature area for too long, I'll add this to the thread:

Happy Perihelion!

"Sunlight falling on Earth at perihelion is 3.5% stronger than the year-long average." Break out the suntan lotion!

I might start a Greeting Cards line, ha ha.

We've had the success of Stardust, Spirit, a meteor shower (Quadrans Muralis) last night, Rik's birthday, and of course perihelion today...it doesn't get any better than this.

--Cindy

Palomar · 2004-01-04 12:28:02

*Checking http://www.spaceweather.com for :::January 4::: (the site is updated and archived daily -- and for whatever reason the archived material is only intermittently postable) will provide a double photo of Sol (each halved): At aphelion (4 July 2003) and perihelion (today...of course).

The photos were taken by Luis Carreira of Portugal; you can easily see the difference in the size of Sol from each "vantage point."

This is the first time I've seen such a comparison.

--Cindy

Palomar · 2004-01-07 08:45:51

Unaided-Eye Sunspot

*One of my friends here was wondering a few months ago (in a different thread) if it'd be possible to see a sunspot during sunset or sunrise [after I'd related then that my husband and I had seen a huge sunspot (#488 in late November) during a thick dust- and sandstorm in our area]. Here's a photo from Mr. Jose Suro of Tierra Verde, Florida, who saw and photographed a huge sunspot (#536) as the sun was setting...this sunspot has approximately 6 times the diameter of our planet. Very striking; lovely photo.

Also includes "green flash" phenomenon. Has anyone here ever witnessed the "green flash"?...I haven't.

--Cindy

Palomar · 2004-01-07 10:33:04

Sun's Twin Found in Scorpius' Left Claw

*Our sun's solar twin is 18 Scorpii and is only 46 light-years from Earth. Wow...that's pretty close, astronomically speaking. They're hoping to find evidence of Earth-type planets orbiting 18 Scorpii (and possible life in that system). This should prove very interesting to keep tabs on; the article says astronomers have been doing just that since 1997.

--Cindy

Byron · 2004-01-07 10:45:38

Sun's Twin Found in Scorpio's Left Claw
*Our sun's solar twin is 18 Scorpii and is only 46 light-years from Earth. Wow...that's pretty close, astronomically speaking. They're hoping to find evidence of Earth-type planets orbiting 18 Scorpii (and possible life in that system). This should prove very interesting to keep tabs on; the article says astronomers have been doing just that since 1997.
--Cindy

I read an article about this in the morning's paper....the comparisions between that star and our Sun is VERY similar, and they haven't found any evidence of any "superplanets" either, which bodes well for the possibility of finding a twin of our own Solar System...wouldn't that be exciting...

B

Shaun Barrett · 2004-01-07 16:45:28

Sounds promising!
It certainly would be fascinating to find a planetary system like our own around a star so similar to Sol. But I guess at our stage of technology, it's going to be difficult to detect an Earth-sized planet at that range ... at least until better instruments are launched into orbit.

I read somewhere the other day that computer simulations are showing interesting limits on the size a rocky planet may attain. Preliminary studies show that a planet not much bigger than Earth is unstable during formation but the details of how it becomes unstable weren't made clear in the very brief article.
I suppose it's possible that rocky planets don't normally get much bigger than Venus and that maybe Earth is that little bit bigger again because of the impactor which produced the Moon(?).
I often think about the unlikely sequence of events which gave rise to this beautiful, stable, life-nurturing world we live on, with its seas and tides and moderate temperatures, and wonder whether it's all too quirky to ever be reproduced somewhere else.
I'd love 18 Scorpii to prove me completely wrong!!

Palomar · 2004-01-13 12:58:25

[=http://www.spaceweather.com/glossary/flareclasses.html]Solar Flare Classification aka "Solar Flare Alphabet Soup"

*Sunspot #537 (very large) is currently facing Earth, and today just slightly off-center and a bit above Sol's "equator." The good folks at spaceweather.com say it poses a risk for X-Class flares.

By the way, if you check spaceweather.com daily, you can see the progression of the sun's rotation, thanks to the sunspots (comparing archived images).

Another good article (linked to the above) entitled "What is a Solar Flare?":

[http://hesperia.gsfc.nasa.gov/sftheory/flare.htm]http://hesperia.gsfc.nasa.gov/sftheory/flare.htm

Shaun: The info you shared on rocky planets...cool.

As an aside of sorts, my favorite sun-related song is John Denver's "Sunshine on My Shoulders" (...sunshine on the water looks so lovely...)

--Cindy

::EDIT:: I just remembered reading last night in my book, _The Cambridge Encyclopedia of the Sun_, that sunspot activity can vary greatly over a long period of time. For instance, from approximately 1645 to 1715 there were very few to no sunspots observed by scientists of the time (unfortunately the book didn't quote its source for that information).

Palomar · 2004-01-16 09:16:22

*The February 2004 issue of "Astronomy" magazine has an article entitled "The 25 Greatest Astrophotos in History." 1957 is the year in which the Stratoscope Project was created to take high-resolution photos of the sun. The article refers to Stratoscope as "now viewed as a predecessor of the Hubble Space Telescope." It was sent aloft by balloon (Note Please: This thread is dedicated to discussion about **the sun**...not balloons or astrophotography; thank you).

I found this item from centennialofflight.gov site, which is very similar to the article in "Astronomy" magazine:

"Skyhook was one of the first major programs to take advantage of the new balloon technology. On August 19, 1957, an unmanned Skyhook balloon lifted a cargo from the Stratoscope project, a program developed through the National Center for Atmospheric Research (NCAR) with the cooperation and joint sponsorship the National Science Foundation (NSF), the U.S. Navy, and the National Aeronautics and Space Administration (NASA). The main instrument was a 12-inch (30-centimeter) telescope with a special light-sensitive pointing system and a closed circuit television camera that researchers could guide?the first balloon-borne telescope. The telescope took more than 400 photographs of sunspots. These were the sharpest photographs taken of the sun up to that time. The photographs increased scientists' understanding of the motions observed in the strong magnetic fields of the sunspots."

--Cindy

Palomar · 2004-01-20 06:58:28

[=http://science.nasa.gov/spaceweather/images2004/20jan04/midi_anim.gif]Animation of sunspot growth

*This item was found at spaceweather.com.

"Just yesterday sunspot 542 was tiny and sunspot 543 didn't exist. Today both are big sunspots: watch them grow. Meanwhile, sunspot 540 has developed a complex magnetic field that could unleash an X-class solar flare."

I've mentioned previously that I wasn't aware sunspots developed so quickly, until discovering spaceweather.com and keeping able to keep tabs on them on a daily basis.

--Cindy

::EDIT:: Found this via link (oh goodie, another space weather site!!):

[http://www.ips.gov.au/Main.php?CatID=8& … r%20Flares]Australian Space Weather Agency

Palomar · 2004-01-23 11:21:14

[=http://www.sunspot.noao.edu/]National Solar Observatory

*Includes -live- images of Sol. Also: Facilities, site map, projects, locations, general information.

[http://www.astronomy.com/Content/Dynami … 5hoijh.asp]Candidates for world's largest solar telescope (down to 3)

*Ultimate choice dependent upon factors such as low humidity and dust levels, generally clear skies, few airline vapor trails, etc...

[http://www.astronomy.com/photogallery/g … 6EDB6CB%7D]Amateur pic of solar prominences

*Nice! Dated 2 December 2003. Love that speckled pattern on the Sun...

--Cindy

Palomar · 2004-01-26 12:54:39

*Magnetic filament -- large enough to hold 50 Earths (that'd toast lots of marshmallows, huh?). This photo was taken by Mr. Gary Palmer of California:

*Another image of the same filament, taken by Mr. Vern Raben of Colorado ("Oh wow!" says Raben. "There were numerous intricate spiraling loops hovering above the Sun's west limb. It was one of the most spectacular prominences I have ever seen!"):

*Now this is a weird pic ("Sun Mirage"). "The temperature outside was -45 F, and Graham Stark of Fairbanks, Alaska, didn't want to leave the house. 'I was afraid the camera would freeze to my hand.' So he took this picture through a thick window. It's the sun. 'I have never witnessed such extreme distortions of the sun. At one point it took the shape of a square and at another it resembled a frog.'" (Three other photos taken by Mr. Stark [not as impressive as the one below, IMO] can be viewed via Spaceweather.com archives for 23 January 2004):

--Cindy

Byron · 2004-01-26 13:09:03

Wow! Some *amazing* pics you've posted there...

B

Rxke · 2004-01-26 13:26:04

that last one... couldn't that be because his window was warped? (here in Europe we still have a lot of houses with 19th C windows, they got fabricated 'vertically', a machine took half-liquid sheets out of a bath... then flattened them with rollers, but the result was less than perfect (i *think* it's called the libby owens process, but i could be **completely** wrong...)
today glass is made, floating on quicksilver, i believe, making it much flatter.

Anyway, our windows (the old one) tend to give quite distorted effects sometimes... And i guess in Alaska they'd use at least double glazing mking distortions worse

Palomar · 2004-01-27 15:05:17

that last one... couldn't that be because his window was warped? (here in Europe we still have a lot of houses with 19th C windows, they got fabricated 'vertically', a machine took half-liquid sheets out of a bath... then flattened them with rollers, but the result was less than perfect (i *think* it's called the libby owens process, but i could be **completely** wrong...)
today glass is made, floating on quicksilver, i believe, making it much flatter.
Anyway, our windows (the old one) tend to give quite distorted effects sometimes... And i guess in Alaska they'd use at least double glazing mking distortions worse

*Hi Rik. Well, I guess we're at the mercy of the guy who took the pic, to be honest that the sun doesn't -always- look like that through his windows.

If he's honest, then I should think the sun looking like that would definitely catch his attention. Hmmmmm.

--Cindy

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