APOD: Comet and CME on the Sun (2011 Oct 05)

[APOD Robot]

Comet and CME on the Sun

Explanation: Did a sun-diving comet just cause a solar explosion? Probably not. This past weekend a comet dove toward the Sun and was followed very quickly by a Coronal Mass Ejection (CMEs) from the other side of the Sun. The first two sequences in the above video shows the spectacular unfolding of events as seen by the Sun-orbiting SOHO satellite, while the same events were also captured by both Sun-orbiting STEREO satellites. Now sungrazer comets that break up as they pass near the Sun are not all that rare -- hundreds have been cataloged over the past few years. CMEs are even more common, with perhaps three lesser events occurring even during the eight hours of the above time-lapse movie. Therefore, the best bet of solar scientists is that the two events were unrelated. Another basis for this judgment is that CMEs are caused by rapid changes in the Sun's magnetic field, changes that a small comet seem unlikely to make. Such coincidences are even more likely during periods of high activity on the Sun's surface -- like now.

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[bystander]

Click to play embedded YouTube video.

Did a Comet Hit Cause an Explosion on the Sun?
Universe Today | Nancy Atkinson | 2011 Oct 03
http://asterisk.apod.com/viewtopic.php?t=25467

The comet and the Coronal Mass Ejection
Discover Blogs | Bad Astronomy | 2011 Oct 04
Good video analysis by Phil Plait

Big comet, big CME... big coincidence?
Sungrazing Comets | Karl Battams | 2011 Oct 04
Analysis by Sungrazer researcher

[FlashBlocked]

What the HELL is this?!?!?

Where's my frackin' APODvertisement for new bar coding technologies and the companies that make them?

And.... what's up with posting videos on a so-called picture site?

Can't you guys get anything right?!

[ems57fcva]

I have a hard time not seeing the events as being connected. The comet heads into the Sun, and suddenly there is a double eruption that creates a CME sending stuff out in the direction of the comet's passage! My guess in that the comet disrupted a magnetic field line connecting the two active regions. Otherwise, I cannot account for how something so small could have such a big effect.

[sunman72]

If you look closely at the 512 x 512 resolution STEREO Behind SECCHI EUVI movie for October 1:

http://stereo-ssc.nascom.nasa.gov/brows ... 95_512.mpg ,

it's pretty clear that the eruptive event associated with the CME starts no later than 19:41 UT, and probably a bit before.

Now look at the STEREO Behind COR1 movie:

http://stereo-ssc.nascom.nasa.gov/brows ... r1_512.mpg ;

the leading edge of the comet is no closer than a solar radius (700,000 km) to the solar limb (and the limb at least a quarter of the way around the Sun, at that) at 19:41 UT. I don't think the comet is able to influence the magnetic fields on the other side of the Sun from that far away.

I recommend the discussion of the general issue of sungrazing comet - CME coincidence at:

http://sungrazer.nrl.navy.mil/index.php ... omets_cmes .

[stowaway]

Yay! Astronomy!

[anuradha bhagwat]

icorrect date on the website. It is showing Oct 4 2011

[dunce]

Given that the mass of the comet in this event can be reasonably estimated

What Mass of Metals (iron and others) could influence the magnetic fields in the areas of the sun that are the source of the CME?

[neufer]

Click to play embedded YouTube video.

Did a Comet Hit Cause an Explosion on the Sun?
Universe Today | Nancy Atkinson | 2011 Oct 03
http://asterisk.apod.com/viewtopic.php?t=25467

The comet and the Coronal Mass Ejection
Discover Blogs | Bad Astronomy | 2011 Oct 04
Good video analysis by Phil Plait

Big comet, big CME... big coincidence?
Sungrazing Comets | Karl Battams | 2011 Oct 04
Analysis by Sungrazer researcher

Click to play embedded YouTube video.

<<Tether Ball Rules: A player can commit a violation by stepping onto his opponent’s half of the pole, by catching and throwing the ball (a “crossy”), by striking the rope instead of the ball (a “ropey”), by hitting the ball twice before it has either circled the pole or been returned by the opponent or, in some variants, struck the pole (a “double touchie”). Generally, after a violation occurs, the game pauses and the ball is returned to the position it was in before the violation; the number of wraps around the pole is re-created (or a penalty-wrap is awarded to the player who did not commit the foul). The player who did not commit the violation then serves the ball. If, however, the violation appears to be intentional, it may result in loss of game.

Tetherball has long been a favorite of school yards, campers, and those who enjoy spending time in parks. While the goal of the game is simple- to wrap the string of the tetherball around the pole it is tethered to by knocking it back and forth- the thrill of competition makes it far more complex. The movie “Napolean Dynamite” attracted new players as well, after watching the title character play the game in the movie. The history of tetherball is somewhat unclear- it’s not an “official” sport with a governing body or committee, which means that any history of the sport is little more than an urban legend. One favorite rendition says that in the ninth century, the Tartars would attach the severed head of a defeated opponent to a rope, tie it to a pole, and then knock it back and forth just for fun. The pole used in the gruesome sport was called a barber pole, a reference to the barbarian nature of the Tartars. Perhaps a more likely explanation refers to the tradition of dancing around a maypole. Long ago, residents of small farming villages would gather around a tree or pole and dance around it while holding ribbons or garlands. The setup of a modern tetherball and tetherball court makes this seem a more likely origin for the game, and one description of the game calls it a “cross between volleyball and a maypole dance.” Maybe the most believable history of the game is simply that tetherball was invented after volleyball in the late 1800s. Early tetherballs were simply volleyballs attached to a rope, and the game likely evolved from volleyball. No matter where tetherball originated, the popularity of the sport is hard to ignore. In 2007, the tetherball tournament held in San Diego attracted more than 80 players.>>

[orin stepanek]

Comets seem to be drawn to the Sun like a moth to a flame. Today's APOD was very interesting. I don't believe the two events were related! (The CME and the Comet!)

[Jeff_in_GA]

Thanks, APOD. Much better than yesterday.

[matrtello]

Suppose the sun has a small core at its center that the comet disturbed & this core reacted in some way to cause the outer shell to mass eject.

[michaelpat]

My APOD has been hijacked this week by spamers. Today's picture is of an animal with its head caught in a fence, yesterdays was of a French (a Paris train station) train wreck and the day before was a shot of a forest of fallen trees.

Anybody else getting these spam images?

What gives?

[perko3280]

I've been liking the site for a long time, but posting video of the day instead of picture will send me looking for a new favorite.

[orin stepanek]

My APOD has been hijacked this week by spamers. Today's picture is of an animal with its head caught in a fence, yesterdays was of a French (a Paris train station) train wreck and the day before was a shot of a forest of fallen trees.

Anybody else getting these spam images?

What gives?

The links carry a little humor once in a while.

[owlice]

michaelpat, you are probably using the APOD backgrounder program, which was written before videos became so common on the Web. This program doesn't handle videos, and when something other than an image is the day's APOD, the backgrounder program looks for the first available image amongst the links. See here for more information.

The shot of the fallen trees WAS the APOD for that day. You might want to look at APOD on the web on occasion, as that is the medium for which the site is designed. It's great to have the other options, but sometimes they just don't work as well as the original.

[Wolf Kotenberg]

celestial bankshot. There are rumors the moon was created by a bankshot

[nstahl]

Thus are religions founded. One event then another and it's (too) natural to assume causation. If there was video going around of a CME followed by a comet there'd be a few people thinking CME's cause comets.

[orin stepanek]

michaelpat, you are probably using the APOD backgrounder program, which was written before videos became so common on the Web. This program doesn't handle videos, and when something other than an image is the day's APOD, the backgrounder program looks for the first available image amongst the links. See here for more information.

The shot of the fallen trees WAS the APOD for that day. You might want to look at APOD on the web on occasion, as that is the medium for which the site is designed. It's great to have the other options, but sometimes they just don't work as well as the original.

owlice I thought he was referring these links that were in the explanation!

Click to view full size image

Click to view full size image

[owlice]

Orin, yes, those are the images that user is seeing INSTEAD of the day's APOD. The backgrounder program downloads (or tries to download) the current APOD image and makes it a computer's background image. When an APOD is not a static image, the backgrounder program grabs the first image it can find in the text and downloads that instead. If one doesn't know it does that, confusion results!

[Beyond]

I think it grabbed the cat image just a little toooo hard and stretched it's neck a bit

[Harry TenHerons]

Way to knock it out of the park, APOD ! Yay !

[Psnarf]

The STEREO views are so cool! You can see the object flying above the surface of the sun before vanishing near the center of image. Whatever it was, comet or asteroid, it had to have vaporized high above the surface. I'll go out on a limb here, I think it is impossible for the object to have caused the CME. My feeble grasp of plasma physics leads me to doubt that comets or even asteroids can last very long in a two-million-degree Kelvin environment. If the object did strike the surface causing the CME, it's gotta be space monkeys. No wonder they're so difficult to find, they're hiding just below the surface of the sun.

[neufer]

[url=http://www-ssc.igpp.ucla.edu/personnel/russell/papers/896/][size=150]Mechanism[/size][/url] [size=150]for generating a detached ICME flux rope through [b][u]reconnection[/u][/b] of coronal magnetic fields.[/size]

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Whatever it was, comet or asteroid, it had to have vaporized high above the surface. I'll go out on a limb here, I think it is impossible for the object to have caused the CME. My feeble grasp of plasma physics leads me to doubt that comets or even asteroids can last very long in a two-million-degree Kelvin environment. If the object did strike the surface causing the CME, it's gotta be space monkeys. No wonder they're so difficult to find, they're hiding just below the surface of the sun.

I too doubt striking the surface would have any effect.

However, if the comet were to explode into a high density plasma at some very critical place in the coronasphere it might just trigger the reconnection of coronal magnetic lines leading to a CME.

[hexalm]

[url=http://www-ssc.igpp.ucla.edu/personnel/russell/papers/896/][size=150]Mechanism[/size][/url] [size=150]for generating a detached ICME flux rope through [b][u]reconnection[/u][/b] of coronal magnetic fields.[/size]

---

Whatever it was, comet or asteroid, it had to have vaporized high above the surface. I'll go out on a limb here, I think it is impossible for the object to have caused the CME. My feeble grasp of plasma physics leads me to doubt that comets or even asteroids can last very long in a two-million-degree Kelvin environment. If the object did strike the surface causing the CME, it's gotta be space monkeys. No wonder they're so difficult to find, they're hiding just below the surface of the sun.

I too doubt striking the surface would have any effect.

However, if the comet were to explode into a high density plasma at some very critical place in the coronasphere it might just trigger the reconnection of coronal magnetic lines leading to a CME.

I might be oversimplifying, but it would take EM radiation about 5 seconds to go through the sun (unhindered in a vacuum, anyway), and around 15s to go around it. What I can't seem to remember is if snapping magnetic field lines are limited to the speed of light, or if they sneak around it somehow.

I would assume they can't transmit information to the opposite side of the sun instantaneously, though the only info I can find regarding that is here: http://www.sciencedaily.com/releases/20 ... 233737.htm, in the context of CME features moving at 1/2 million mph (nowhere near the speed of light, not sure if that specifically refers to magnetic field lines, though).