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The Rembrandt impact crater basin on Mercury.  Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Smithsonian Institution/Carnegie Institution of Washington

New Mysteries Unveiled on Mercury

30 Apr , 2009

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Even though Mercury looks like the Moon at first glance, scientists from the MESSENGER mission say it’s becoming apparent that Mercury is an amazingly dynamic planet, and is actually more like Mars. For example, before this mission, scientists weren’t sure if volcanism even existed on Mercury, but from the spacecraft’s two flybys, they now know it is a very important part of the planet’s history. Additional new findings from the second flyby of Mercury in October 2008 show that the planet’s atmosphere, magnetosphere, and geological past are all characterized by much greater levels of activity than scientists first suspected.

And by the way, isn’t this a stunning picture of an impact basin? It’s one of the new discoveries from MESSENGER.

One of the most exciting results from the second flyby of Mercury is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter, and actually, to see the entire basin, it took combined images from both the first and second flyby to create the stunning picture above. Rembrandt is a relatively young impact basin, and forming about 3.9 billion years ago, is younger than any other known impact region on the planet. It shows pristine terrain on the outer portion of the crater, as well as unusual tectonic fault features, not found in any other big crater.

“This is the first time we’ve seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed” says MESSENGER scientist Thomas Watters. “Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows. We know that after Rembrandt formed, the planet was still contracting, so it is an exciting and unique new member of planetary craters we can study.”

MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer, or MASCS, detected significant amounts of magnesium clumped in the planet’s tenuous atmosphere, called the exosphere. Scientists had suspected magnesium would be present, but were surprised at its distribution and abundance.

“Detecting magnesium was not too surprising, but what is surprising is the distribution and amounts of magnesium that was recorded,” said Bill McClintock, a MESSENGER co- investigator.
The instrument also measured other exospheric constituents during the October 6 flyby, including calcium and sodium, and he suspects that additional metallic elements from the surface including aluminum, iron, and silicon also contribute to the exosphere.

The differences in Mercury's magnetosphere in the two flybys by MESSENGER. Credit: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS.

The differences in Mercury's magnetosphere in the two flybys by MESSENGER. Credit: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS.


MESSENGER observed a radically different magnetosphere at Mercury during its second flyby, compared with its earlier January 14, 2008 encounter. In the first flyby, no dynamic features were found. But the second flyby was a totally different situation, said James Slavin, MESSENGER Co-Investigator.

“MESSENGER measured large magnetic flux leakage through the dayside magnetopause, about a factor of 10 greater than even what is observed at the Earth during its most active intervals. The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the Magnetometer throughout the encounter.”

Slavin said Mercury’s magnetic field bears a marked resemblance to what we have at earth, but it is about 100 times weaker, which implies interior of Mercury is in part molten. “There is a dynamo action that is ongoing which regenerates and maintains the planetary magnetic field,” he said.

A subsurface interpretation of an impact basin on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington.

A subsurface interpretation of an impact basin on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington.


Scientists are also learning more abour Mercury’s crustal evolution, and have now mapped about 90% of the planet’s surface. About 40% is covered by smooth plains which are now known to be of volcanic origna. “These plains are globally distributed (in contrast with the Moon, which has a nearside/farside asymmetry in the abundance of volcanic plains),” said Brett Denevi, MESSENGER team member.

Data shows an enhanced iron- and titanium content in an ancient basin studied by MESSENGER, which are exposed on the surface only through impact events, and may formed when dense minerals settled out as they crystallized from a cooling magma. “There are a complex series of events going on here, but we see it everywhere, so this is a microcosm of the entire planet” said Denevi.

These discoveries are more clues to the mystery of the creation of the rocky, bizarre planet that resides closest to the sun.

Source: NASA Press conference, MESSNEGER press release


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solrey
Member
April 30, 2009 2:19 PM
Regarding the magnetic flux leakage, from another article: “On Mercury, though, the twisters were 10 times as strong as any magnetic cyclones observed on Earth. With so little atmosphere to interfere, Mercury’s magnetic tornadoes are great spinning chutes that ionized gas can slide down.” “They act as magnetic channels or open windows that allow solar wind plasma from the sun, very fast and very hot, to come right down those field lines and impacts the surface,” said Jim Slavin of NASA Goddard Spaceflight Center. When the gas hits the surface, it knocks off neutrally-charged atoms and sends them on a loop high into the sky.” That’s a pretty good description of Electric Discharge Machining! This is what I’ve… Read more »
HelloBozos
Member
April 30, 2009 2:29 PM

i just cought Mercury from my backyard with a 8″ telescope last weekend..its tricky cause it sets so fast..

http://www.celestronimages.com/details.php?image_id=3408

was the night after the Cresant Moon,Mercury an The Pleiades conjunction which was neat to view

Nereid
Member
Nereid
April 30, 2009 3:09 PM

“Electric Discharge Machining”? Is that some kind of personal theory, which Fraser’s announcement specifically said should not be promoted here?

Lawrence B. Crowell
Member
Lawrence B. Crowell
April 30, 2009 7:07 PM

This what I meant! There is no real physics behind what solrey, Anaconda, Oilsmastery and the rest talk about. They are good at throwing words around which have physics content, or borrowing buzz phrases from plasma physics, but there is little content to much of what they say.

Lawrence B. Crowell

solrey
Member
April 30, 2009 11:50 PM
lbc, nereid…better take that up with NASA. They describe the process as “sputtering”, which is what electric discharge machining does. In that diagram, the surface effects are labeled as sputtering. A discharge vortex, or “magnetic tornado”, results in surface sputtering (knocking off neutrally charged atoms) which is electric discharge machining. Any flow of charged particles (“magnetic vortex”) that rips atoms from, or deposits atoms into, the surface of an electrode (the surface of Mercury) is EDM. It can result in excavation, or deposition, of material on the surface. From Wiki: “The term electronic sputtering can mean either sputtering induced by energetic electrons (for example in a transmission electron microscope), or sputtering due to very high-energy or highly charged… Read more »
Nereid
Member
Nereid
May 1, 2009 7:17 AM
@solrey: if all you are doing is using electric discharge machining as a synonym for sputtering, then it would have been a good idea for you to have said so in your first comment (though why you would choose to capitalise it – Electric Discharge Machining – I don’t know). However, you didn’t stop at that; instead, you went on claim that the “plumes” and “jets” on Io and Enceladus are caused by the same mechanism (sputtering). Further, you made things even more confusing by adding “discharge vortices” to the mix, thereby making up your own, idiosyncratic, definition of electric discharge machining (the normal use of this term, as a manufacturing process, does not involve “discharge vortices”). I… Read more »
Nereid
Member
Nereid
May 1, 2009 7:41 AM
@Lawrence B. Crowell: my only prior exchange of comments with solrey came in response to his (her?) April 27th, 2009 at 8:21 am one, on the UT Did Dark Matter Annihilate Our Early Universe? story. In that comment, solrey wrote: “Yes there is a viable, alternative theory. But ya’ll ignore it or scoff at it, hurling insults and ridicule towards those who realize the validity of the theory. And now we’re not even supposed to invoke it’s [sic] name here.” To which I responded: “I’m rather at a loss to know what to say. MOND, and the various extensions which seek to incorporate relativity, is not ignored, not scoffed at, etc. Far from it; there are dozens and… Read more »
Ivan3man_At_Large
Member
Ivan3man_At_Large
May 1, 2009 11:22 AM

Nereid:

I’ve not exchanged comments with OilIsMastery, but someone wrote that Total Science seems to be the same person…

Yeah, it was me! smile

Nereid
Member
Nereid
May 1, 2009 11:29 AM

testing

testing (blockquote)

testing (bold)

Nereid
Member
Nereid
May 1, 2009 11:33 AM

OK, so now I know!

Thanks IVAN3MAN

Out of curiosity, do you recall if OilIsMastery provided a Peratt quote with reference(s) for Plasma Cosmology predicting that the CMB would have a temperature of 2.8K? I asked Total Science to provide one, and he (she?) has been silence ever since.

Ivan3man_At_Large
Member
Ivan3man_At_Large
May 1, 2009 1:26 PM

@ Nereid,

I don’t recall whether OilIsMastery had ever quoted Peratt, but Anaconda has often cited Anthony (“Dead Parrot”) Peratt — with links to “Thunderbolts.info” — on numerous occasions here and especially at Bad Astronomy — much to the annoyance of everybody there!

DrFlimmer
Member
DrFlimmer
May 1, 2009 3:04 PM

Hooray, finally. I just created a new email account somewhere else (I don’t know why the other THREE failed…) and know: Here I am wink.

So, good evening everybody!

Btw: Solrey, before presenting new details of your theory, please answer my question from some time ago: How is it possible that large neutral gas clouds (mostly consisting of hydrogen, detected by the 21-cm-line) are flying around in galaxies with the same velocity as the stars, although they should not be affected strongly by em-forces?

Nereid
Member
Nereid
May 1, 2009 4:40 PM

Welcome DrFlimmer.

The name seems familiar; have you, perchance, been a contributor to comments on the Cosmic Variance blog? Or the Bad Astronomer’s one (they’re both now hosted on Discover)?

damian
Member
May 1, 2009 9:17 PM

Err, Mercury, amazing. smile

Its interesting to hear about the variability of its magnetosphere, I guess we will learn more once Messenger is in orbit. But I wonder if its change has something to do with its elliptical orbit. The dynamo being affected by its proximity to the sun? Tidal forces?

So many mysteries.

I wish we had instruments to see below the surface of planets. It remains undiscovered country, even here on earth.

Ivan3man_At_Large
Member
Ivan3man_At_Large
May 2, 2009 1:36 PM
Anaconda: It would seem “sputteirng” [sic] is an electromagnetic process. Dictionary.com: sputter — verb (used without object) 1. to make explosive popping or sizzling sounds. 2. to emit particles, sparks, etc., forcibly or explosively, esp. accompanied by sputtering sounds. 3. to eject particles of saliva, food, etc., from the mouth in a light spray, as when speaking angrily or excitedly. 4. to utter or spit out words or sounds explosively or incoherently, as when angry or flustered. –verb (used with object) 5. to emit (anything) forcibly and in small particles, as if by spitting: The fire sputtered cinders. 6. to eject (saliva, food, etc.) in small particles explosively and involuntarily, as in excitement. 7. to utter explosively and… Read more »
DrFlimmer
Member
DrFlimmer
May 2, 2009 7:44 AM

@ Nereid

Yes, I am the same wink I always use this nickname. I participate at Bad Astronomy and also at Universe Today before, but I wasn’t able to register because I didn’t receive the confirmation mails due to whatever reasons. But, well, now it worked and I am happy wink.

Jon Hanford
Member
Jon Hanford
May 2, 2009 8:43 AM

I wonder if this magnetic phenomena is (at this level of intensity) limited to Mercury due to its proximity to the Sun, its’ chemical-mineral makeup and-or its’ size? This magnetic peculiarity my also help explain “sworls” of material next to some craters as opposed to the usual ‘ray’ pattern. @Dr Flimmer, glad to see you back again. As you can see, not much has changed. But that sure is a great picture of a giant basin ( …..or an example of “Electric Discharge Machining”???) on the surface of Mercury, no smile

Anaconda
Member
Anaconda
May 2, 2009 10:32 AM
Interesting… Electromagnetism is found to have a significant role in Mercury’s near-space environoment and even at the surface (“sputtering”), hey, it’s NASA that chose the term, and comparing the Wikipedia entry for “sputtering” and NASA’s description of the process on Mercury, I’d say the processes are similar. This similarity, a result of electromagnetic processes being scale independent, is why what goes on in a plasma physics laboratory is relevant to processes observed & measured on and around the various planets in the solar system (it may even form a basis for prediction and understanding). As for the follow-up comments to solrey’s comments, they seem focussed on definitions — a reasonable concern — but as always, substance takes precedent… Read more »
star-grazer west coast
Member
star-grazer west coast
May 2, 2009 11:57 AM

I am disregarding all other comments posted on this feed.I am glad the Messenger Mission will once and for all photograph and scan the entire planet, surprizes comes in quite small packages like Mercury- the crater is hugh!!!! Perhaps in several decades, some hardened tough rover-type vehicles can explore this harsh world!!!!

Anaconda
Member
Anaconda
May 2, 2009 3:05 PM

@ Ivan3Man:

And your comment is designed to do what?

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