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Astronomy Picture of the Day 5-08-02
NASA ^ | 5-08-02 | Robert Nemiroff and Jerry Bonnell

Posted on 05/08/2002 5:09:37 AM PDT by petuniasevan

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 May 8
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Sunspot Loops in Ultraviolet
Credit: TRACE Project, NASA

Explanation: It was a quiet day on the Sun. The above image shows, however, that even during off days the Sun's surface is a busy place. Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius. Large sunspot group AR 9169 is visible as the bright area near the horizon. The bright glowing gas flowing around the sunspots has a temperature of over one million degrees Celsius. The reason for the high temperatures is unknown but though to be related to the rapidly changing magnetic field loops that channel solar plasma. Sunspot group AR 9169 moved across the Sun during 2000 September and decayed in a few weeks.


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: astronomy; gas; glowing; image; loop; photography; solar; sun; sunspot; ultraviolet; uv
Since ultraviolet radiation is blocked by Earth's atmosphere, this kind of photography must be done from orbit.

This beautiful image is courtesy of the Transition Region and Coronal Explorer. TRACE is a mission of the Stanford-Lockheed Institute for Space Research (a joint program of the Lockheed-Martin Advanced Technology Center's Solar and Astrophysics Laboratory and Stanford's Solar Observatories Group ), and part of the NASA Small Explorer program.

Get on the APOD PING list!

1 posted on 05/08/2002 5:09:37 AM PDT by petuniasevan
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To: MozartLover; Joan912; NovemberCharlie; snowfox; Dawgsquat; viligantcitizen; theDentist; grlfrnd...
APOD PING!
2 posted on 05/08/2002 5:10:36 AM PDT by petuniasevan
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To: petuniasevan
WOW!!!

AWESOME picture!!!!
3 posted on 05/08/2002 5:14:04 AM PDT by wafflehouse
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To: petuniasevan
I sat behind a girl with hair like this on a bus in Olympia Wa! Swear to God!!! Great Picture!!!
4 posted on 05/08/2002 5:14:07 AM PDT by sleavelessinseattle
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To: sleavelessinseattle
I think I found her WEBSITE.
5 posted on 05/08/2002 5:25:28 AM PDT by StriperSniper
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To: StriperSniper;2Trievers;Bad~Rodeo
AYEEE MY EYES!!!MY EYES!!!
6 posted on 05/08/2002 5:33:45 AM PDT by sleavelessinseattle
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To: petuniasevan
Thank you for the daily ping. All the pictures are amazing.
7 posted on 05/08/2002 5:47:36 AM PDT by DallasGal
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To: petuniasevan
Is that a host blocking part of the sun ???

old inside joke, hehe

8 posted on 05/08/2002 6:00:37 AM PDT by fnord
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To: petuniasevan
Wow! The HF ought to be jammin!

73's

9 posted on 05/08/2002 6:02:56 AM PDT by dd5339
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To: fnord
Ping ClassyGreenEyedBlonde!
10 posted on 05/08/2002 6:05:31 AM PDT by petuniasevan
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To: petuniasevan
Sun-sational! Thanks for the ping. :)
11 posted on 05/08/2002 6:12:06 AM PDT by Dixie Mom
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To: sleavelessinseattle
Is that the only thing burning!? LOL &;-)
12 posted on 05/08/2002 6:52:28 AM PDT by 2Trievers
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To: 2Trievers
My fear of bald punk rocker chicks is honestly acquired, Miss, I DID survive the Cobain Grunge period in Seattle, afterall, Haughty sniff.
13 posted on 05/08/2002 7:08:31 AM PDT by sleavelessinseattle
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To: sleavelessinseattle
I prefer some historical context to my punk! &;-)

Apologies to 'tunia! &;-)

14 posted on 05/08/2002 7:18:47 AM PDT by 2Trievers
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To: petuniasevan
Now that's a BBQ pit!
15 posted on 05/08/2002 8:20:37 AM PDT by aomagrat
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To: petuniasevan
Did you remember to send royalty payment to Virgiliu Pop for photographing his sun?
16 posted on 05/08/2002 9:25:41 AM PDT by RightWhale
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To: petuniasevan
LOL :-)
17 posted on 05/08/2002 9:34:55 AM PDT by fnord
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To: petuniasevan
Great picture!
18 posted on 05/08/2002 1:05:47 PM PDT by sistergoldenhair
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To: petuniasevan
Thanks for the ping.

Beautiful picture of the Sun.

19 posted on 05/08/2002 4:38:18 PM PDT by Vigilantcitizen
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To: petuniasevan
Since ultraviolet radiation is blocked by Earth's atmosphere, this kind of photography must be done from orbit.

Beautiful picture! Did you know that some insects can see well into the UV range? I wonder if that was ever a useful ability on Earth.

20 posted on 05/08/2002 5:22:44 PM PDT by Helix
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To: Helix
Like honeybees, for instance.
Here's a chart of wavelength sensitivity for human vision and bee vision.


This is a comparison of wavelengths visible to humans and bees.
The range of vision for the bee and butterfly extends into the ultraviolet.
The petals of the flowers they pollinate have special ultraviolet patterns
which guide the insects deep into the flower.

This doesn't contradict my earlier assertion that UV imaging must be done from orbit; obviously a little UV gets through. It's what gives you a tan (or sunburn). It's just that 99% of "soft" UV is blocked, and higher-energy "hard" UV is 100% blocked, as are X-Rays.

21 posted on 05/08/2002 5:49:01 PM PDT by petuniasevan
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To: Helix
Daylilies in normal daylight visible spectrum.

Same daylilies in UV light.

Although we can't be sure exactly HOW UV light appears to bees, it seems that the UV image above shows dark central regions in the flowers which guide the bee to the nectar.

22 posted on 05/08/2002 6:03:19 PM PDT by petuniasevan
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To: Helix
Ordinary yellow weedy dandelions become rare jewels in UV light.


23 posted on 05/08/2002 6:06:19 PM PDT by petuniasevan
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To: petuniasevan
Beautiful pictures and a damned good point! That'll teach me to be less vague in my musings! My old bio professors would kill me if they knew I had (lazily) suggested insects didn't ever use UV.

To be honest, I had wandered off track and into a supposition about the stable atmosphere we enjoy today.

I vaguely remembered reading about a theory of Fred Hoyle's on the ability of Drosophila (I think) to see the very short (980 A)wavelengths of UV which, according to him, could never have penetrated the atmosphere during the time that insects have been present on Earth. Therefore, he believed they were under no selective pressure to develop such an ability. He also thought the insects could not have survived the light's mutagenic effects.

These assertions always seemed a little over-the-top to me since we've witnessed how much the atmosphere can change in just the few years scientists been studying it. The constant change of the "hole" in the ozone, for example. And although UV light is a mutagen, all organisms have some ability to repair the damage. It seems possible that, at one time, shorter UV rays were able to penetrate the atmosphere and the ability to see these wavelengths was used by those insects.

24 posted on 05/08/2002 8:36:02 PM PDT by Helix
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