APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

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APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by APOD Robot » Wed Feb 10, 2010 4:54 am

Image Sakurajima Volcano with Lightning

Explanation: Why does a volcanic eruption sometimes create lightning? Pictured above, the Sakurajima volcano in southern Japan was caught erupting early last month. Magma bubbles so hot they glow shoot away as liquid rock bursts through the Earth's surface from below. The above image is particularly notable, however, for the lightning bolts caught near the volcano's summit. Why lightning occurs even in common thunderstorms remains a topic of research, and the cause of volcanic lightning is even less clear. Surely, lightning bolts help quench areas of opposite but separated electric charges. One hypothesis holds that catapulting magma bubbles or volcanic ash are themselves electrically charged, and by their motion create these separated areas. Other volcanic lightning episodes may be facilitated by charge-inducing collisions in volcanic dust. Lightning is usually occurring somewhere on Earth, typically over 40 times each second.

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RJN
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Post by RJN » Wed Feb 10, 2010 6:52 am

Quiz: Can anyone identify the starfield behind the volcano?

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by neufer » Wed Feb 10, 2010 11:35 am

Well, let's see:
  • 1) hot temps insure low relative humidity
    2) there is lots of rubbing going on.
Sounds like a good static electricity situation to me.

Maybe Sakurajima is even a large Van de Graaff generator:
  • Image
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by emc » Wed Feb 10, 2010 12:32 pm

Very interesting… World Of Wonder! Where else can you get burned, shot, beaten and electrocuted all at the same time?

Very cool images on Martin Rietze's website 8-)
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by azurelune » Wed Feb 10, 2010 2:26 pm

This picture of the lightning in the volcanic eruption has been dated February 9 and should read February 10

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Post by emc » Wed Feb 10, 2010 2:42 pm

RJN wrote:Quiz: Can anyone identify the starfield behind the volcano?
My confidence is very low... smoky at best... but it would be apropros if the background includes Draco.

I believe I can spot NodusI right of starfield center and Chi Draconis on the left
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by RJN » Wed Feb 10, 2010 3:47 pm

emc: Good guess but I don't think that is right.

azurelune: Thank you. My bad. I just fixed the date.

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by neufer » Wed Feb 10, 2010 6:15 pm

RJN wrote:emc: Good guess but I don't think that is right.
The nearly parallel tracks (as opposed to circular tracks) must indicate
that we are looking pretty much either due East or due West.

I'll guess that we are looking pretty much due West and that
the three aligned stars in the center are part of Andromeda.
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by RJN » Wed Feb 10, 2010 7:41 pm

No, good guess again but it is not Andromeda. Here is a clue: the volcano was imaged from the east. Bigger clue: the image taken on 9.1.2010 at 18h43m48s local time.

BTW, I notice that the Digg counts are comparatively low for this APOD, which I find surprising given the seemingly dramatic presentation. Does this surprise anyone else?

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by emc » Wed Feb 10, 2010 9:15 pm

Do I get another guess? Even with your excellent clues, I’m still having difficulty matching the patterns. Now I think we are looking toward Pegasus and Equuleus is behind the plume. But I am bias.
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by RJN » Wed Feb 10, 2010 11:49 pm

Don't have it yet! I will post the answer on Thursday.

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by emc » Thu Feb 11, 2010 12:41 pm

RJN wrote:...I notice that the Digg counts are comparatively low for this APOD, which I find surprising given the seemingly dramatic presentation. Does this surprise anyone else?
I just signed up to DIGG (took me a good deal of scrolling to get to my birth year – bummed me out)

My first impression is that DIGG is very commercial… thankfully APOD is not. This APOD may get more DIGGS in time but apparently most folks that visit APOD are not members of DIGG.

I noticed that the Jan 29, 2006 APOD had 2259 DIGGS
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by bystander » Thu Feb 11, 2010 1:58 pm

Huh, and it doesn't even have a digg link. :?

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by RJN » Thu Feb 11, 2010 3:42 pm

The photographer said, in an email, that the stars in the background are "from Aquarius-Delphinus border". Here is the image he sent in:
Image

The preview shows that the right part of the image has been cut off. So to see the whole image, I suggest isolating it in its own browser window.

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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by emc » Thu Feb 11, 2010 9:41 pm

Thank you for posting the answer. As I already knew, my astronomer skills need a good deal of work! But it was fun trying to find the right answer.

And thank you for APOD and Asterisk. I’m making friends and having a great deal of fun plus learning a thing or two.
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by neufer » Thu Feb 11, 2010 11:47 pm

RJN wrote:The photographer said, in an email, that the stars in the background are "from Aquarius-Delphinus border".[/img]
Oh, darn :!:

And I was intimately familiar with the asterisms along the "Aquarius-Delphinus border". :wink:
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by neufer » Fri Feb 12, 2010 2:03 am

emc wrote:Now I think we are looking toward Pegasus and Equuleus is behind the plume.
Pegasus with the foal Equuleus next to it, as depicted in Urania's Mirror,
a set of constellation cards published in London c.1825.
The horses appear upside-down in relation to the constellations around them.
Image
In Greek mythology, one myth associates Equuleus with the horse struck from Neptune's trident,
during the contest between him and Athena when deciding which would be the superior.
http://en.wikipedia.org/wiki/Equuleus wrote:
<<Equuleus is Latin for 'little horse', i.e. a foal. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is the second smallest of the modern constellations (after Crux), spanning only 72 square degrees. It is also very faint, having no stars brighter than the fourth magnitude.

Image>>
http://www.areavoices.com/astrobob/index.cfm?archive=2009-08 wrote:
<<I'm thinking of three little constellations that don't get much recognition from skywatchers. Well, maybe Delphinus the Dolphin does because it's just so cute, but the other two tend to get passed up because they're overshadowed by the Milky Way and whoop-de-doo constellations like the Northern Cross or Pegasus. We're talking about Sagitta (Sah-JIT-tuh) the Arrow, Equuleus (ek-KWOO-lee-us) the Little Horse and the more familiar Delphinus (del-FINE-us) the Dolphin. They march down from below the Northern Cross toward Enif in Pegasus like three floats in a parade. Why not set up a lawn chair and watch them pass by? From Altair stretch out your arm and use your fist to hop up to the arrow and over to the dolphin and foal.

Image
Image

Some small constellations like Leo Minor and Lynx are relatively new entries in the heavenly lineup. They were created in the 17th century by celestial mapmakers who assembled faint stars between the traditional constellations into new ones. Our three minis however are of ancient vintage and as well known to the Greeks as they are to seekers in the 21st century.

I don't think you'll have a problem seeing Delphinus and even Sagitta, but Equuleus will need more attention since none of its stars is brighter than the 4th magnitude, two levels fainter than the stars of the Big Dipper.>>
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Re: APOD: Sakurajima Volcano with Lightning (2010 Feb 10)

Post by RJN » Fri Feb 12, 2010 9:06 pm

emc wrote: I’m making friends and having a great deal of fun plus learning a thing or two.
And thank you, emc (and everybody), for your contributions to the Asterisk. I am hopeful that the new design is perceived by most as a bit more fun than the old one. I am finding it so myself.