Comments and questions about the
APOD on the main view screen.
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APOD Robot
- Otto Posterman
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Post
by APOD Robot » Sat Dec 19, 2009 4:55 am
Aurora Shimmer, Meteor Flash
Explanation: Northern Lights, or
aurora borealis, haunted
skies over the island of Kvaløya, near Tromsø Norway on December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from December's excellent
Geminid meteor shower. Streaking past familiar stars in the handle of the
Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurorae and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but
auroras are caused by energetic charged particles from the
magnetosphere, while meteors are trails of
cosmic dust.
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haosci
- Asternaut
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by haosci » Sat Dec 19, 2009 12:01 pm
It appears that this beautiful scene also has a background of noctoluminescent clouds.
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neufer
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by neufer » Sat Dec 19, 2009 1:04 pm
haosci wrote:It appears that this beautiful scene also has a background of noctoluminescent clouds.
Except that
noctilucent clouds occur:
1)
at least 15 kilometers
below the ionospheric Aurora Borealis
2) and
in the summertime!
So this is most likely a multiple exposure including wintertime
nacreous clouds:
http://www.lightningwizard.com/AurNLC.php wrote:
<<Aurora Borealis (also called "Northern Lights") and Noctilucent Clouds (abbreviated as "NLC") are beautiful phenomena that occur far above the daily weather. They may be called "space weather". Aurora is caused by streams of charged particles from the sun entering Earth's atmosphere. The charged particles collide with oxygen and nitrogen atoms in the ionosphere at altitudes over 100 km. These atoms then emit the usually red and green colored light we see. The magnetic field of the Earth leads the stream of particles to the poles. A few days after an Earth-directed solar eruption, the Northern Lights can incidentally also be observed closer towards the equator.
Noctilucent Clouds (NLC) are silvery to blueish white fragile looking clouds in the night sky, roaming in the mesosphere at about 80-85 km altitude. They can be seen at [polar] latitudes mostly from late May to early August, with a maximum around 21 June. In that time of year, temperatures at those altitudes are coldest, allowing the small amounts of water vapour to condensate on meteor dust. The clouds are seen because the sun does not go far below the horizon, so that the sun still illuminates the very high clouds.>>
Art Neuendorffer
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TBIRD7777
- Asternaut
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by TBIRD7777 » Sat Dec 19, 2009 1:51 pm
I'm guessing this photo has been posted before, I have not checked. But in the notes below it states that this was taken on Dec. 13th, And it was taken on Dec. 13th, but Dec. 13th 2007. The impression they have given is that it was taken in 2009, so they should re-write their blurb, or put the year in. No big deal I know, but when re-hashing already posted photos, it's always good to check. This is by far one of the Top sites in the history of the Internet, so why am I being so anal? I would just like to see them make as few mistatkes as possible. - TBIRD7777
![Very Happy :D](./images/smilies/icon_biggrin.gif)
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geckzilla
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by geckzilla » Sat Dec 19, 2009 2:26 pm
I couldn't find the photo posted anywhere 2 years ago. I'm guessing his camera clock was set to the wrong year. Or maybe he did take it two years ago with the devious plot of releasing it in 2009, claiming to have captured the meteor during a different meteor shower! ...Calling Mr. Occam, cleanup on aisle 4.
Just call me "geck" because "zilla" is like a last name.
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BMAONE23
- Commentator Model 1.23
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by BMAONE23 » Sat Dec 19, 2009 4:00 pm
Another great "Chance Encounter" with a famous constellation... The meteor flash is perfectly allighed with the first 3 handle stars of the
Big Dipper Megrez, Alioth, & Mizar
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bystander
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by bystander » Sat Dec 19, 2009 6:19 pm
geckzilla wrote:I'm guessing his camera clock was set to the wrong year. Or maybe he did take it two years ago with the devious plot of releasing it in 2009, claiming to have captured the meteor during a different meteor shower!
I'm not Occam, but I'm guessing the clock was wrong. I can't imagine what conspiracy your other plot would support.
![Laughing :lol:](./images/smilies/icon_lol.gif)
As shown in APOD's link
Geminid meteor shower, Mr. Hansen's photo is included in Space Weather's 2009 Geminid Meteor Gallery. Could this be evidence of a
time traveler from the past?
![Wink :wink:](./images/smilies/icon_wink.gif)
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SittingDownMan
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by SittingDownMan » Sun Dec 20, 2009 1:44 am
APOD Robot wrote:Aurora Shimmer, Meteor Flash (2009 Dec 19)
by APOD Robot » Sat Dec 19, 2009 4:55 am
Aurora Shimmer, Meteor Flash
... but aurora are caused by energetic...
No. "*
Aurorae* are" or "the aurora *is* "...
That one bugs me almost as much as authors insisting "nexus" is plural.
.....................SDM............:>
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Chris Peterson
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by Chris Peterson » Sun Dec 20, 2009 2:32 am
SittingDownMan wrote: No. "*Aurorae* are" or "the aurora *is* "...
Or even better,
"auroras are".
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geckzilla
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by geckzilla » Sun Dec 20, 2009 3:05 am
Oh gosh, here we go with the plural-of-whatever again.
![Laughing :lol:](./images/smilies/icon_lol.gif)
I made sure to include one of each for you two. Too bad I can't change the APOD itself.
![Smile :)](./images/smilies/icon_smile.gif)
Just call me "geck" because "zilla" is like a last name.
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SittingDownMan
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by SittingDownMan » Sun Dec 20, 2009 3:21 am
geckzilla wrote:Oh gosh, here we go with the plural-of-whatever again.
![Laughing :lol:](./images/smilies/icon_lol.gif)
I made sure to include one of each for you two. Too bad I can't change the APOD itself.
![Smile :)](./images/smilies/icon_smile.gif)
Ok. Whatever.
"Auroras". From a self-styled scientist, forsooth.
I'm too old for this playground, obviously.
Bye.
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geckzilla
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by geckzilla » Sun Dec 20, 2009 3:32 am
Well, that's an interesting thing to get upset about. You say po-tay-toe, I say po-tah-toe? We all get along?
Just call me "geck" because "zilla" is like a last name.
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bystander
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by bystander » Sun Dec 20, 2009 4:07 am
SittingDownMan wrote:Ok. Whatever.
"Auroras". From a self-styled scientist, forsooth.
I'm too old for this playground, obviously.
According to
Merriam-Webster and
Wiktionary auroras is the preferred form, although both are acceptable.
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Chris Peterson
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by Chris Peterson » Sun Dec 20, 2009 4:44 am
SittingDownMan wrote:Ok. Whatever.
"Auroras". From a self-styled scientist, forsooth.
I'm too old for this playground, obviously.
Relax, it wasn't a criticism of you! It was just a light-hearted reference to a discussion a week or two ago.
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neufer
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by neufer » Sun Dec 20, 2009 1:47 pm
I notice that
Merriam-Webster doesn't even attempt to
pronounce auroras.
Art Neuendorffer
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Case
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by Case » Sun Dec 20, 2009 2:30 pm
...aurora also means 'dawn'. Didn't know that until today.
![Very Happy :D](./images/smilies/icon_biggrin.gif)
I, for one, like Roman numerals.
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neufer
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by neufer » Sun Dec 20, 2009 4:37 pm
Case wrote:...aurora also means 'dawn'. Didn't know that until today.
![Very Happy :D](./images/smilies/icon_biggrin.gif)
My youngest daughter is named DAWN.
It was either that or CREPUSCULA.
CREPUSCULAR: a. Pertaining to twilight; glimmering; noting the imperfect
light of the morning and evening; hence, imperfectly clear or luminous.
Art Neuendorffer
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DavidLeodis
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by DavidLeodis » Sun Dec 20, 2009 6:19 pm
It is a superb image. Without the information in the explanation I doubt I would have known that the handle of the Big Dipper (The Plough to me!) was there. Not having the ploughshare bit I would not have recognised it otherwise!
![Embarassed :oops:](./images/smilies/icon_redface.gif)
but I don't think I need be.
![Smile :)](./images/smilies/icon_smile.gif)
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bystander
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by bystander » Sun Dec 20, 2009 6:50 pm
neufer wrote:My youngest daughter is named DAWN. It was either that or CREPUSCULA.
Thank goodness! I hate to think what it would be like going thru life with a name like Crepuscula.