APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3571
Joined: Fri Dec 04, 2009 3:27 am

APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by APOD Robot » Sun Apr 21, 2019 4:06 am

Image Spiral Aurora over Icelandic Divide

Explanation: Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization. In 1859, following notable auroras seen all across the globe, a pulse of charged particles from a coronal mass ejection (CME) associated with a solar flare impacted Earth's magnetosphere so forcefully that they created the Carrington Event. A relatively direct path between the Sun and the Earth might have been cleared by a preceding CME. What is sure is that the Carrington Event compressed the Earth's magnetic field so violently that currents were created in telegraph wires so great that many wires sparked and gave telegraph operators shocks. Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced. The featured aurora was imaged in 2016 over Thingvallavatn Lake in Iceland, a lake that partly fills a fault that divides Earth's large Eurasian and North American tectonic plates.

<< Previous APOD This Day in APOD Next APOD >>

Boomer12k
:---[===] *
Posts: 2507
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by Boomer12k » Sun Apr 21, 2019 6:30 am

A crazy "@" symbol with a TAIL!!

Awesome.

:---[===] *

User avatar
Ann
4725 Å
Posts: 9565
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by Ann » Sun Apr 21, 2019 6:40 am

Boomer12k wrote:
Sun Apr 21, 2019 6:30 am
A crazy "@" symbol with a TAIL!!

Awesome.

:---[===] *
:lol2: :clap:

Ann
Color Commentator

User avatar
orin stepanek
Plutopian
Posts: 4830
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by orin stepanek » Sun Apr 21, 2019 12:14 pm

Nice Photo of a strange phenomenon! (IMO) Do you suppose that resulted from a spiral flare? :shock: :thumb_up:
Orin

Smile today; tomorrow's another day!

AlbireoA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by AlbireoA » Sun Apr 21, 2019 12:56 pm

This picture was already used on 2016 August 30... :cry: :cry:

NHcycler

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by NHcycler » Sun Apr 21, 2019 1:06 pm

AlbireoA wrote:
Sun Apr 21, 2019 12:56 pm
This picture was already used on 2016 August 30... :cry: :cry:
Your point is??

Reminiscent of the Tadpole Galaxy APOD of a few days ago!

E Fish
Ensign
Posts: 49
Joined: Thu Mar 09, 2017 2:29 pm

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by E Fish » Sun Apr 21, 2019 1:29 pm

Aren't Sunday images always repeats?

That is a gorgeous image, though. And a nice combination of astronomy and geology, two of my favorite sciences! :)

BDanielMayfield
Don't bring me down
Posts: 1983
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by BDanielMayfield » Sun Apr 21, 2019 1:50 pm

Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced.
Then it's fortunate that we appear to heading into a period of low sunspot activity. The downside is that aurora's would become much rarer.

Bruce
"Happy are the peaceable ... "

User avatar
Chris Peterson
Abominable Snowman
Posts: 14384
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by Chris Peterson » Sun Apr 21, 2019 2:05 pm

BDanielMayfield wrote:
Sun Apr 21, 2019 1:50 pm
Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced.
Then it's fortunate that we appear to heading into a period of low sunspot activity. The downside is that aurora's would become much rarer.
Auroras remain quite common even when the Sun is very inactive. But they are far less likely to move outside of high latitudes, so the likelihood of seeing them for most people is much smaller.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

BDanielMayfield
Don't bring me down
Posts: 1983
Joined: Thu Aug 02, 2012 11:24 am
AKA: Bruce
Location: East Idaho

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by BDanielMayfield » Sun Apr 21, 2019 3:09 pm

Chris Peterson wrote:
Sun Apr 21, 2019 2:05 pm
BDanielMayfield wrote:
Sun Apr 21, 2019 1:50 pm
Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced.
Then it's fortunate that we appear to heading into a period of low sunspot activity. The downside is that aurora's would become much rarer.
Auroras remain quite common even when the Sun is very inactive. But they are far less likely to move outside of high latitudes, so the likelihood of seeing them for most people is much smaller.
I now live at about 43deg 58' north, but didn't move far enough, apparently.
"Happy are the peaceable ... "

User avatar
Chris Peterson
Abominable Snowman
Posts: 14384
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by Chris Peterson » Sun Apr 21, 2019 3:36 pm

BDanielMayfield wrote:
Sun Apr 21, 2019 3:09 pm
Chris Peterson wrote:
Sun Apr 21, 2019 2:05 pm
BDanielMayfield wrote:
Sun Apr 21, 2019 1:50 pm


Then it's fortunate that we appear to heading into a period of low sunspot activity. The downside is that aurora's would become much rarer.
Auroras remain quite common even when the Sun is very inactive. But they are far less likely to move outside of high latitudes, so the likelihood of seeing them for most people is much smaller.
I now live at about 43deg 58' north, but didn't move far enough, apparently.
Or south.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
orin stepanek
Plutopian
Posts: 4830
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by orin stepanek » Sun Apr 21, 2019 4:19 pm

E Fish wrote:
Sun Apr 21, 2019 1:29 pm
Aren't Sunday images always repeats?

That is a gorgeous image, though. And a nice combination of astronomy and geology, two of my favorite sciences! :)
Almost always! :mrgreen: OTTO needs a day off once in a while also! 8-)
Orin

Smile today; tomorrow's another day!

dlw
Ensign
Posts: 70
Joined: Fri Jul 22, 2005 4:43 pm
Location: California

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by dlw » Sun Apr 21, 2019 7:03 pm

Might that red streak reflected on the lake be a meteor from behind the clouds?
You do not have the required permissions to view the files attached to this post.

ems57fcva
Ensign
Posts: 72
Joined: Wed Feb 24, 2010 1:13 am
Location: Falls Church, VA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by ems57fcva » Sun Apr 21, 2019 9:41 pm

Nice aurora. But I have a few quibbles about the caption.

1) The water in the picture appears to be a moving stream, not a lake. And that water looks to me to be no more than a few hundred feet wide at most, while Thingvallavatn Lake covers an area of 32 square miles. I have been at that lake, and even from a the cliffs near its northern shore you cannot see the southern shore.

2) What Thingvallavatn Lake partially fills is not a fault but a rfit valley. This is because the North American and Eurasian plates are pulling apart there instead of sliding past each other. (Also, the east side of Thingvallavatn actually belongs to a microplate and the Eurasian plate begins at another rift valley over 50 miles east of there. But that is subtle detail and is almost not worth mentioning.)

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 836
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by alter-ego » Mon Apr 22, 2019 1:09 am

dlw wrote:
Sun Apr 21, 2019 7:03 pm
Might that red streak reflected on the lake be a meteor from behind the clouds?
It is possible. The streak coincidentally is short enough and apparently in the right position to be hidden by the cloud that's partially covering Taurus, coincidentally pointing near the Perseid radiant, and is coincidental with the nominal shower duration. The image is dated Aug 24.
 
Aurora &amp; Meteor.JPG
You do not have the required permissions to view the files attached to this post.
A pessimist is nothing more than an experienced optimist

User avatar
Joe Stieber
Science Officer
Posts: 157
Joined: Tue Aug 18, 2009 1:41 pm
Location: Maple Shade, NJ

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by Joe Stieber » Mon Apr 22, 2019 1:49 am

alter-ego wrote:
Mon Apr 22, 2019 1:09 am
dlw wrote:
Sun Apr 21, 2019 7:03 pm
Might that red streak reflected on the lake be a meteor from behind the clouds?
It is possible. The streak coincidentally is short enough and apparently in the right position to be hidden by the cloud that's partially covering Taurus, coincidentally pointing near the Perseid radiant, and is coincidental with the nominal shower duration. The image is dated Aug 24.
I’d be inclined to think that it’s the glitter path reflection of Aldebaran, which is just below the tail end of the white arrow in alter-ego’s annotated clip. Not far to the right of that, there’s a faint glitter path of Theta 1 & 2 Tau.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 16011
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by neufer » Mon Apr 22, 2019 1:51 am

ems57fcva wrote:
Sun Apr 21, 2019 9:41 pm

1) The water in the picture appears to be a moving stream, not a lake. And that water looks to me to be no more than a few hundred feet wide at most, while Thingvallavatn Lake covers an area of 32 square miles. I have been at that lake, and even from a the cliffs near its northern shore you cannot see the southern shore.
It appears to be the extreme northern section of Thingvallavatn Lake
from a point just off the highway due south of Drekkingarhylur.

64°15'39.9"N 21°07'17.4"W
Art Neuendorffer

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 836
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by alter-ego » Mon Apr 22, 2019 2:28 am

Joe Stieber wrote:
Mon Apr 22, 2019 1:49 am
alter-ego wrote:
Mon Apr 22, 2019 1:09 am
dlw wrote:
Sun Apr 21, 2019 7:03 pm
Might that red streak reflected on the lake be a meteor from behind the clouds?
It is possible. The streak coincidentally is short enough and apparently in the right position to be hidden by the cloud that's partially covering Taurus, coincidentally pointing near the Perseid radiant, and is coincidental with the nominal shower duration. The image is dated Aug 24.
I’d be inclined to think that it’s the glitter path reflection of Aldebaran, which is just below the tail end of the white arrow in alter-ego’s annotated clip. Not far to the right of that, there’s a faint glitter path of Theta 1 & 2 Tau.
Yeah, maybe.
I thought the same thing at first, but I didn't think intensity of the streak is not consistent with Aldebaran's brightness and brightness of the nearby star reflections which are questionable as being streaks. However, Aldebaran is 7x to 8x brighter than Tau 2, so maybe all is consistent with smearing by water ripples.
A pessimist is nothing more than an experienced optimist

ems57fcva
Ensign
Posts: 72
Joined: Wed Feb 24, 2010 1:13 am
Location: Falls Church, VA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by ems57fcva » Mon Apr 22, 2019 4:56 am

neufer wrote:
Mon Apr 22, 2019 1:51 am
ems57fcva wrote:
Sun Apr 21, 2019 9:41 pm

1) The water in the picture appears to be a moving stream, not a lake. And that water looks to me to be no more than a few hundred feet wide at most, while Thingvallavatn Lake covers an area of 32 square miles. I have been at that lake, and even from a the cliffs near its northern shore you cannot see the southern shore.
It appears to be the extreme northern section of Thingvallavatn Lake
from a point just off the highway due south of Drekkingarhylur.

64°15'39.9"N 21°07'17.4"W
I am able to confirm that location as the site for the picture. Even so, there is an obvious flow of water in that picture if you know what to look for. I assume that the stream that flows into that arm of the lake was running high when that picture was taken.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 16011
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by neufer » Mon Apr 22, 2019 1:55 pm

alter-ego wrote:
Mon Apr 22, 2019 2:28 am
Joe Stieber wrote:
Mon Apr 22, 2019 1:49 am
alter-ego wrote:
Mon Apr 22, 2019 1:09 am

It is possible. The streak coincidentally is short enough and apparently in the right position to be hidden by the cloud that's partially covering Taurus, coincidentally pointing near the Perseid radiant, and is coincidental with the nominal shower duration. The image is dated Aug 24.
I’d be inclined to think that it’s the glitter path reflection of Aldebaran, which is just below the tail end of the white arrow in alter-ego’s annotated clip. Not far to the right of that, there’s a faint glitter path of Theta 1 & 2 Tau.
Yeah, maybe. I thought the same thing at first, but I didn't think intensity of the streak is not consistent with Aldebaran's brightness and brightness of the nearby star reflections which are questionable as being streaks. However, Aldebaran is 7x to 8x brighter than Tau 2, so maybe all is consistent with smearing by water ripples.
The nearness of the pond would imply that
the reflected image is virtually identical to the direct image
(i.e., no revealed sky features that are not directly observable).

Hence, it would seem to be Aldebaran.
Art Neuendorffer

dlw
Ensign
Posts: 70
Joined: Fri Jul 22, 2005 4:43 pm
Location: California

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by dlw » Mon Apr 22, 2019 4:46 pm

Yes -- stretched by the rippling water...

[attachment=0]Aldebaran.jpg[/attachment]
You do not have the required permissions to view the files attached to this post.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 16011
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by neufer » Mon Apr 22, 2019 7:44 pm


dlw wrote:
Mon Apr 22, 2019 4:46 pm

Yes -- stretched by the rippling water...
And possibly also focused by the rippling water waves parallel to the streak
which you have pointing to the Pleiades on the right
although caused by Aldebaran on the left.
Art Neuendorffer

dlw
Ensign
Posts: 70
Joined: Fri Jul 22, 2005 4:43 pm
Location: California

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by dlw » Mon Apr 22, 2019 7:58 pm

I always learn something new here!

Thanks!

khh

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by khh » Mon Apr 22, 2019 8:43 pm

A Rapture hook!

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 836
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: Spiral Aurora over Icelandic Divide (2019 Apr 21)

Post by alter-ego » Tue Apr 23, 2019 4:08 am

neufer wrote:
Mon Apr 22, 2019 1:55 pm
...
The nearness of the pond would imply that
the reflected image is virtually identical to the direct image
(i.e., no revealed sky features that are not directly observable).

Hence, it would seem to be Aldebaran.
I agree. At least my original assertion of several coincidences is true. That's all they are :)
A pessimist is nothing more than an experienced optimist