How Magnetic Tornadoes Might Regenerate Mercury's Atmosphere
Written by Brian Ventrudo
Compared to Earth, Mercury doesn't have much of an atmosphere. The smallest rocky planet has weak surface gravity, only 38% that of Earth. And the scorching-hot daytime surface temperatures of 800 degrees Fahrenheit (approximately 450 degrees Celsius) should have boiled away any trace of Mercury's atmosphere long ago. Yet recent flybys of the MESSENGER spacecraft clearly revealed Mercury somehow retains a thin layer of gas near its surface. Where does this atmosphere come from?
"Mercury's atmosphere is so thin, it would have vanished long ago unless something was replenishing it," says Dr. James A. Slavin of NASA's Goddard Space Flight Center, Greenbelt, Md., a co-investigator on NASA's MESSENGER mission to Mercury.
The solar wind may well be the culprit. A thin gas of electrically charged particles called a plasma, the solar wind blows constantly from the surface of the sun at some 250 to 370 miles per second (about 400 to 600 kilometers/second). According to Slavin, that's fast enough to blast off the surface of Mercury through a process called "sputtering", according to Slavin. Some sputtered atoms stay close enough to the surface to serve as a tenuous yet measurable atmosphere.
But there's a catch – Mercury's magnetic field gets in the way. MESSENGER's first flyby on January 14, 2008, confirmed that the planet has a global magnetic field, as first discovered by the Mariner 10 spacecraft during its flybys of the planet in 1974 and 1975. Just as on Earth, the magnetic field should deflect charged particles away from the planet's surface. However, global magnetic fields are leaky shields and, under the right conditions, they are known to develop holes through which the solar wind can hit the surface.
During its second flyby of the planet on October 6, 2008, MESSENGER discovered that Mercury’s magnetic field can be extremely leaky indeed. The spacecraft encountered magnetic "tornadoes" – twisted bundles of magnetic fields connecting the planetary magnetic field to interplanetary space – that were up to 500 miles wide or a third of the radius of the planet.
"These 'tornadoes' form when magnetic fields carried by the solar wind connect to Mercury's magnetic field," said Slavin. "As the solar wind blows past Mercury's field, these joined magnetic fields are carried with it and twist up into vortex-like structures. These twisted magnetic flux tubes, technically known as flux transfer events, form open windows in the planet's magnetic shield through which the solar wind may enter and directly impact Mercury's surface."
Venus, Earth, and even Mars have thick atmospheres compared to Mercury, so the solar wind never makes it to the surface of these planets, even if there is no global magnetic field in the way, as is the case for Venus and Mars. Instead, it hits the upper atmosphere of these worlds, where it has the opposite effect to that on Mercury, gradually stripping away atmospheric gas as it blows by.
The process of linking interplanetary and planetary magnetic fields, called magnetic reconnection, is common throughout the cosmos. It occurs in Earth's magnetic field, where it generates magnetic tornadoes as well. However, the MESSENGER observations show the reconnection rate is ten times higher at Mercury.
"Mercury's proximity to the sun only accounts for about a third of the reconnection rate we see," said Slavin. "It will be exciting to see what's special about Mercury to explain the rest. We'll get more clues from MESSENGER's third flyby on September 29, 2009, and when we get into orbit in March 2011."
Slavin's MESSENGER research was funded by NASA and is the subject of a paper that appeared in the journal Science on May 1, 2009.
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and after flybys of Earth, Venus, and Mercury will start a yearlong study of its target planet in March 2011. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.
Source: NASA
Filed under: Astronomy, Mercury, Solar System
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June 3rd, 2009 at 6:44 pm
No doubt that bloody Anaconda will turn up again to sell his usual brand of Snake Oil "Electric Universe" cosmology to explain everything!
June 3rd, 2009 at 8:23 pm
Good to see Messenger paying handsome dividends already. Should be a veritable deluge of science when it settles into orbit…
June 4th, 2009 at 4:54 am
Well, isn't this a blast?
D'oh! I assumed that thermal heating was primarily responsible for the atmosphere. Preferential sputtering by light ions is an even better explanation why light elements such as sodium are mentioned, or why water is seen. (Presumably solar wind hydrogen interacting with oxide minerals, or just liberating what's already in the rocks.)
IVAN3MAN, do you know if Anaconda and ilk is picturing snakes … eh, electrons all the way down? I assume gravitons and other particles are "illusions of scientists", and that those with direct connection with the electronic cosmic mind knows who's in charge.
[Not that it is terribly interesting to untangle the confused web of thoughts of someone who can't even master how to apply math but assumes (s)he does, but I can't resist some primitive pattern matching and labeling of my own. "Look, there goes the rare turtles all the way down believer!"]
June 4th, 2009 at 5:06 am
Um, "untangle" denialist claims is the wrong claim of course. It's not doable as there are false assertions in there so one can add on stuff to show anything with such a mess, including contradictions.
"Prod" confused ideas is probably a better description. (Always a risky business around poisonous snakes!)
June 5th, 2009 at 11:45 am
There was no reason to comment, the schematic speaks for itself: It has ELECTROMAGNETISM written all over it!
As far as Larsson's criticism? Well, let's see:
Larsson states, "I assume gravitons and other particles are 'illusions of scientists'…"
Last time I looked NOBODY has even CLAIMED to have found "gravitrons". It's a prediction of Quantum Mechanics…because…well…er…according to QM there has to be a particle for every force…so there must be "gravitrons".
Lots of Luck
Larsson states: "Um, “untangle” denialist claims is the wrong claim of course. It’s not doable as there are false assertions in there so one can add on stuff to show anything with such a mess, including contradictions."
You and "modern" astronomy should look in the mirror.
But perhaps a group hug will do.
June 5th, 2009 at 1:37 pm
What is "ELECTROMAGNETISM", Anaconda?
I mean, what do mean by the term in your comment?
Specifically, how does your view of "ELECTROMAGNETISM" differ from
a) Maxwell's equations?
b) QED?
Please be as specific as you can.
Please also state, clearly, the extent to which your view of "ELECTROMAGNETISM" may be described as consistent with contemporary physics.
June 5th, 2009 at 3:03 pm
IVAN3MAN Says
I am merely an amateur astronomer, and mostly into observational studies of whatever my telescope and CCD can pick up. Without mentioning names, you are correct that person with various brands of snake oil has returned!!!!!! Lol Where some alcoholic may have a cast-iron stomach to drink rut-gut wine and diesel fuel, this person must have a cast-iron patience to continously absorb
all types of downgrading, name-calling and is a glutton for more punishment!!!!! lol
June 5th, 2009 at 4:42 pm
@ Nereid:
What do I mean by electromagnetism?
That charged particles, electrons and ions, plasma, flow from the Sun to (in this case) Mercury, via Birkeland currents and once at Mercury interact with Mercury's magnetosphere and surface in various processes as labled on the schematic in this post.
Pretty simple.
Oh, almost forgot and, of course, this is all entirely consistent with the tenents of Plasma Cosmology.
Even if it does give you and others a case of indigestion
June 5th, 2009 at 6:23 pm
Thanks for the swift response, Anaconda.
Unfortunately, I don't understand what you wrote:
If I may, here's what I think your general idea of "ELECTROMAGNETISM" is:
* a flow of charged particles in the IPM.
If so, then that seems to me to be just another name for "the solar wind".
But your comment also includes mention of Birkeland currents, and interactions with planetary magnetospheres and surfaces.
To what extent are Birkeland currents an essential part of your concept of "ELECTROMAGNETISM"?
To what extent is the interaction of the solar wind with planetary magnetospheres and/or surfaces an essential part of your concept of "ELECTROMAGNETISM"?
Finally, is your concept of "ELECTROMAGNETISM" restricted to the solar system?
June 6th, 2009 at 5:01 am
@ Nereid:
Review the schematic.
Notice the spirals that are labled, "Flux Transfer Events", this is simply another name for Birkeland currents.
The title of the post calls them magnetic tornadoes.
They are a filamentary flow of electric currents constrained by tubular magnetic fields generated by the electric currents.
Remember, you can't have "magnetic" without the "electro"
Obviously, electromagnetism is a broad general term.
Nereid states: "If I may, here’s what I think your general idea of “ELECTROMAGNETISM” is: * a flow of charged particles in the IPM. If so, then that seems to me to be just another name for 'the solar wind'."
Not exactly. The solar wind is a subset of electromagnetism. Birkeland currents are a subset of electromagnetism. The solar wind and Birkeland currents are two seperate electromagnetic phenomena, although, related.
The solar wind is the general tenuous flow of charged particles from the Sun in all directions possibly concentrated at the Sun's heliospheric current sheet often times referred to as the Parker spiral. Birkeland currents as stated, above, are a concentrated filamentary flow of electric currents constrained by tubular magnetic fields generated by the electric currents.
Nereid asks: "To what extent are Birkeland currents an essential part of your concept of 'ELECTROMAGNETISM'?"
They are a basic component because they are a transport mechanism of electric currents in space. As Hannes Alfven, the Nobel Prize winner stated: Birkeland currents are the electric cables in space, which transport electrical energy over long distances.
Nereid asks: "To what extent is the interaction of the solar wind with planetary magnetospheres and/or surfaces an essential part of your concept of 'ELECTROMAGNETISM'?"
"Essential" would not be the word I would employ. Rather, the interaction of the solar wind with planetary magnetospheres and/or surfaces (and the Birkeland currents as well) is a process of electromagnetism which as the, above, schematic shows, can be divided into further processes and phenomena.
Nereid asks: "Finally, is your concept of “ELECTROMAGNETISM” restricted to the solar system?"
No.
June 6th, 2009 at 5:28 am
Is light "ELECTROMAGNETISM"?
Is light "a subset of electromagnetism"?
Is the photoelectric effect either "ELECTROMAGNETISM" or "a subset of electromagnetism"?
Is the Compton effect either "ELECTROMAGNETISM" or "a subset of electromagnetism"?
Is synchrotron radiation either "ELECTROMAGNETISM" or "a subset of electromagnetism"?
June 6th, 2009 at 10:31 am
@ Anaconda, above you state that the diagram / illustration "has electromagnetism written all over it". Could you please provide peer-reviewed, published papers concerning specifically the Messenger observations and a strict PU-EU interpretation of these observations made by the MESSENGER probe? Possibly something beyond your unsubstantiated claims (and no press releases, blog stories, podcasts, etc.) ?
June 6th, 2009 at 12:35 pm
@ Anaconda,
I presume that my harmonious associates will concur when I request that you eschew obfuscation and espouse elucidation.
June 6th, 2009 at 12:41 pm
One more question if I may, Anaconda: what is "electrical energy"?
(bold added)
Oh, and do you have a source for this? Specifically, in which publication did Alfvén state this (or, if at a conference, what conference)?
June 6th, 2009 at 4:42 pm
Anaconda:
Nereid:
We know very well where the source for that and other stuff that Anaconda quotes; I just wonder if he remembered to wash his hands afterwards?
June 8th, 2009 at 10:51 pm
@ Anaconda:
*Crickets*
June 9th, 2009 at 9:34 am
@ Ivan3Man:
Your humor is juvenile and can be fun at times, but your scientific penetration is limited.
At the moment I can't find the "electric power cables in space" quote from Hannes Alfven, but I do have this one that is an equivalent:
"In order to understand the phenomena in a certain plasma region, it is necessary to map not only the magnetic but also the electric field and the electric currents. Space is filled with a network of currents which transfer energy and momentum over large or very large distances. The currents often pinch to filamentary or surface currents. The latter are likely to give space, as also interstellar and intergalactic space, a cellular structure." — Hannes Alfven, plasma physicist, 1970 Nobel Prize winner
Source: Wikipedia, foot noted for source of above quote.
http://en.wikipedia.org/wiki/Hannes_Alfv%C3%A9n
June 9th, 2009 at 9:38 am
@ Nereid:
What Hannes Alfven and others focussed on was the electron/ion electricity dynamic.
That should be clear to you, now, but I see you still are into passive/aggressive questions.
June 9th, 2009 at 1:08 pm
Anaconda:
Must everything have sexual connotations with you, Anaconda?
June 9th, 2009 at 3:18 pm
Anaconda states "At the moment I can’t find the “electric power cables in space” quote from Hannes Alfven….". And this is the response from the PU/EC/EU proponent(s) ? Who is lacking in 'scientific penetration' now? Anaconda can't seem to find a whole host of relevant papers that have been asked of him (and solrey, too, for that matter). As IVAN3MAN so eloquently put it "I presume that my harmonious associates will concur when I request that you eschew obfuscation and espouse elucidation."
June 10th, 2009 at 4:16 am
@ Jon Hanford:
"Space is filled with a network of currents which transfer energy and momentum over large or very large distances."
What does that mean to you?
June 10th, 2009 at 6:12 am
Anaconda,
I think you have some questions to answer first. Like some quantifiable EU/PC models that can be compared to astronomical observations. Currently the consensus is that such models are lacking despite the hupla you and other proponents have been making.
June 10th, 2009 at 10:41 am
I have discovered that at least one person has tried to explain to you that not all currents are Birkeland currents, and not all currents *in plasmas* are Birkeland currents … it seems that you didn't understand what they were trying to tell you …
Why do you think this is equivalent to the statement you gave earlier (supposedly by Alfvén)?
I am much more clued up now, Anaconda … it seems that much of what you write is simply your own, personal, ideas, formed in part by applying a narrow selection of stuff that you mis-remember from your school days, and using faulty logic (the fallacy of false dichotomy, for example).
In any case, what examples can you give (at least one please) of "currents which transfer energy and momentum over large or very large distances" in astronomy? Please, exclude the solar system.
June 10th, 2009 at 3:15 pm
@ Nereid:
The double helix that comes out of the Milky Way's Active Galactic Nucleus.
Nereid asks: "Why do you think this is equivalent to the statement you gave earlier (supposedly by Alfvén)?"
Simple, that's what "electric cables" do, they transfer electrical energy over large distances, it's an analogy.
June 11th, 2009 at 8:06 am
Thanks for the reply, Anaconda.
I was not aware that the Milky Way has an AGN; may I ask if you made this up, or you read it somewhere? If the latter, would you be kind enough to provide the source?
What is "The double helix"?
How did you conclude that this thing is “current(s) which transfer energy and momentum over large or very large distances”?
June 11th, 2009 at 11:40 am
@ Nereid2,
"Nereid2"? Twin brother of Nereid?
Anyway, I think that this is what Anaconda is referring to: Double Helix Nebula.
June 11th, 2009 at 12:38 pm
@ Nereid,
Here's a more detailed article linked at the bottom of the Wikipedia article:
Double Helix Nebula Near Center of the Milky Way.
June 11th, 2009 at 1:58 pm
@ Anaconda,
Both of those articles refer to a super-massive black hole at the centre of the Milky Way galaxy. So there!
June 11th, 2009 at 3:19 pm
@Anacona: One more time, the Milky Way Galaxy, the galaxy in which we reside, does not currently have an Active Galactic Nucleus! It may have once been an AGN and it may become an AGN in the future, but it is in no way is it considered to currently exhibit Active Galactic activity at this time. If you have a properly referenced paper that states otherwise, I'd be more than glad to admit my error. You have repeatedly made this exact error in previous posts and then admit you may have been in error. Note to Anaconda: THERE IS CURRENTLY NO AGN AT THE CENTER OF OUR GALAXY.
June 12th, 2009 at 4:55 am
@IVAN3MAN: for you, I will be Nereid's (dizygous) twin brother … or anyone else you wish me to be … (well, not ANYONE); after all, as the saying goes, on the internet no one knows you're a dog!
Or you can accept a more mundane explanation, such as me being away from home, and not having taken my WP PW with me (and so having had a need to create a new account …).
June 17th, 2009 at 12:09 am
@ Nereid,
Oops!