APOD: Mercury's Surface in Exaggerated Color (2011 Jun 16)

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APOD: Mercury's Surface in Exaggerated Color (2011 Jun 16)

Post by APOD Robot » Thu Jun 16, 2011 4:05 am

Image Mercury's Surface in Exaggerated Color

Explanation: The robotic MESSENGER spacecraft recently completed over 100 orbits of Mercury. Messenger's cameras have recorded detailed pictures utilizing eight different colors across visible and near infrared light, exploring the surface composition and looking for clues to the history and evolution of the solar system's innermost planet. This sharp image combines three of the MESSENGER wide angle camera's colors, but in exaggerated fashion. Otherwise, to the unaided human eye, Mercury's surface colors would appear comparatively muted. The image is about 1,000 kilometers across and features as small as a single kilometer are discernible at the original resolution. Today, the Messenger project will release new images and science findings from the first spacecraft to orbit Mercury.

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ucuicme

Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by ucuicme » Thu Jun 16, 2011 4:48 am

Is most of that astriod impact still there cause it must have hit slow to still remain intact like that.

mulsar

Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by mulsar » Thu Jun 16, 2011 6:58 am

I'm wondering if the multitude of straight strings of craters, ususally with increasing sizes along the path of the string, you see all over the photo are comet impacts, comets that have broken up due to gravatational forces simular to the Shoemaker-Levy 9 impact on Jupiter. Maybe Mercury has been sweeping up comets for eons, problably protecting the outer planets from comet impacts.

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by bystander » Thu Jun 16, 2011 7:13 am

Know the quiet place within your heart and touch the rainbow of possibility; be
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garry

Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by garry » Thu Jun 16, 2011 9:52 am

mulsar wrote:I'm wondering if the multitude of straight strings of craters, ususally with increasing sizes along the path of the string, you see all over the photo are comet impacts, comets that have broken up due to gravatational forces simular to the Shoemaker-Levy 9 impact on Jupiter. Maybe Mercury has been sweeping up comets for eons, problably protecting the outer planets from comet impacts.
Yes it is interesting that in this small picture, numerous crater chains, Like Mars which is not close to the Sun. If a comet broke into pieces, you would not get a straight line; As the nucleus breaks up before impact, the pieces would NOT fall into place behind each other and impact in a perfectly straight line. The pieces would be moving away slightly from each other. And like Mars, the crater chains are all the same size; This would mean that each piece would have to break up in exactly the same size to form constant craters.(Mass X Velocity), Oh yes, all the craters are perfect circles.; Which means they would always have to hit at a perpendicular angle, or close to it.

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by neufer » Thu Jun 16, 2011 10:24 am

mulsar wrote:
I'm wondering if the multitude of straight strings of craters, usually with increasing sizes along the path of the string, you see all over the photo are comet impacts, comets that have broken up due to gravitational forces similar to the Shoemaker-Levy 9 impact on Jupiter.
Quite possibly.
Last edited by neufer on Thu Jun 16, 2011 12:30 pm, edited 1 time in total.
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by owlice » Thu Jun 16, 2011 11:19 am

Pretty planet, whether the colors are exaggerated or not.

Re: round craters, I am under the impression that most impacts will leave round craters, even if not perpendicular or nearly so. Is my impression incorrect?
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mattunes

Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by mattunes » Thu Jun 16, 2011 12:06 pm

I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people (the unattributed vertical scale exaggerations commonly found on, i.e. Mars images, is also most objectionable). I get that there's info in there that's invisible otherwise, but for me the images are just hideous, Warhol-esque perversions of the real thing, and they become worse than meaningless without detailed explanations, as huge numbers of naive people see them and think that's what the object looks like. As an amateur astronomer who does public watches, I'm always explaining why the objects lack all those reds, purples, greens, blues, and yellows. Please, APOD editors, show us what we would actually see as the default, then link to the "enhanced" image with lots of explanation as to why the colors are chosen and what they represent. Thanks! Matt in Florida

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by orin stepanek » Thu Jun 16, 2011 12:21 pm

The planet don't seem to be dusty like Luna; like it is very solid and clean looking!
Orin

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by richard schumacher » Thu Jun 16, 2011 12:59 pm

I prefer the MESSENGER website at the Johns Hopkins University APL:
http://messenger.jhuapl.edu/

mattunes

Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by mattunes » Thu Jun 16, 2011 1:37 pm

"If a comet broke into pieces, you would not get a straight line; As the nucleus breaks up before impact, the pieces would NOT fall into place behind each other and impact in a perfectly straight line. The pieces would be moving away slightly from each other. And like Mars, the crater chains are all the same size; This would mean that each piece would have to break up in exactly the same size to form constant craters.(Mass X Velocity), Oh yes, all the craters are perfect circles.; Which means they would always have to hit at a perpendicular angle, or close to it."

Wrong on all counts: in line? yes, see SL-9, and the hundreds of crater chains (catenas) identified on the moon and elsewhere; craters the same size? possible for breakup to produce impactors of approximately the same scale, and within the resolution of this image, yes; angle/circle? only very oblique, low angle, impacts produce elliptical craters (see Schiller on Moon), most angles of impact produce essentially circular ones.

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by neufer » Thu Jun 16, 2011 1:43 pm

mattunes wrote:
I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people (the unattributed vertical scale exaggerations commonly found on, i.e. Mars images, is also most objectionable). I get that there's info in there that's invisible otherwise, but for me the images are just hideous, Warhol-esque perversions of the real thing, and they become worse than meaningless without detailed explanations, as huge numbers of naive people see them and think that's what the object looks like. As an amateur astronomer who does public watches, I'm always explaining why the objects lack all those reds, purples, greens, blues, and yellows. Please, APOD editors, show us what we would actually see as the default, then link to the "enhanced" image with lots of explanation as to why the colors are chosen and what they represent.
http://en.wikipedia.org/wiki/Fetishism wrote:
<<Fetishism is the attribution of inherent value or powers to an object. A fetish (French fétiche; Portuguese feitiço; Latin facticius, "artificial" and facere, "to make") is an object believed to have supernatural powers.>>
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Chris Peterson » Thu Jun 16, 2011 2:38 pm

mattunes wrote:I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people (the unattributed vertical scale exaggerations commonly found on, i.e. Mars images, is also most objectionable). I get that there's info in there that's invisible otherwise, but for me the images are just hideous, Warhol-esque perversions of the real thing, and they become worse than meaningless without detailed explanations, as huge numbers of naive people see them and think that's what the object looks like.
You say that you "get" the fact that there's info that can only be seen this way, but I'd argue that the rest of your statement suggests you don't get it at all!

Once again, this is about science. It isn't about aesthetics- although many may find today's image (and images using different palettes in general) to be very aesthetic, indeed.
As an amateur astronomer who does public watches, I'm always explaining why the objects lack all those reds, purples, greens, blues, and yellows.
Me too. And I consider it a superb opportunity to introduce ideas that most people have never considered.
Please, APOD editors, show us what we would actually see as the default, then link to the "enhanced" image with lots of explanation as to why the colors are chosen and what they represent.
Happily, that's not going to happen. Many of the images shown here are not even collected in visual light bands to begin with. How should they be displayed- as a black box linked to some other visual version? This site is about how scientific imagery enhances our knowledge, how such images can be beautiful in their own right. So we have images made in the light of radio through x-rays, or even in the "light" of gravity, and displayed in whatever colorspace is most appropriate for getting across the point of the imager.
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Orca » Thu Jun 16, 2011 6:14 pm

Happily, that's not going to happen. Many of the images shown here are not even collected in visual light bands to begin with. How should they be displayed- as a black box linked to some other visual version?
Do you suppose this goes back to the tendency people have to think of the visible part of the spectrum as "how things really appear?"

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Beyond » Thu Jun 16, 2011 7:21 pm

It would seem to me that just about everything that we see in this solar system has impact written all over it. Even this planet, though much is covered by foliage. This solar system sure must have been a really WILD place early on. Atlas must have gotten in a lot of batting practice before things settled down. It also looks like he might have dropped a bag of flour on mercury. :mrgreen:
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Dyavalon » Thu Jun 16, 2011 7:57 pm

I find the large complex crater just right of center that appears to have a nearly perfectly centered, smaller, second impact, with that containing the typical uplift center of a complex crater. It is interesting that this appears to have had an impact, a collapse, then possibly a second impact in the center of the first.

I also notice to the "right" side of that same large crater the whole "eastern" edge appears to have be undermined and collapsed as one large unit. I wonder what geology would allow for the surface to remain suspended above the impact zone. It reacts like it was either heaved as one large unit (didn't melt) only to collapse back down, or was undermined over time only to collapse by some other natural process. Either way it tells me that the upper crust must be made of some material which is much stronger than the underlying material.

I can't wait to see higher resolution images. There are a number of structures in this picture that are inconsistent with being impact craters, and point to some other mechanism creating a "spongy looking" surface texture. Areas that appear to be recessed that have no symmetrical structure. They could be very ancient, small, impact craters that have just been re-impacted and distorted over time. Or possibly evidence of volcanic collapse of the subsurface maybe?

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by bystander » Thu Jun 16, 2011 8:44 pm

Happy 16th Anniversary, APOD!

Thanks to Robert and Jerry for providing us 16 years of wonderful images and commentary!
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Early MESSENGER science results

Post by neufer » Thu Jun 16, 2011 8:56 pm

http://www.planetary.org/blog/article/00003067/ wrote:
The Planetary Society Blog
By Emily Lakdawalla Jun. 16, 2011
Early MESSENGER science results: Mercury is its own planet, not Moon or Earth

<<There was a press briefing today giving some early science results from MESSENGER and it was surprisingly meaty. I'm going to focus on just one set of the results that they presented. As usual with MESSENGER, the most exciting stuff is not from the "pretty pictures," although there were some of those, which you can see at the page full of visuals for the press briefing. What's most exciting out of Mercury is what we're learning from the other, relatively arcane instruments on MESSENGER. Whenever you send a spacecraft to orbit a planet for the first time, you're going to wreck a lot of people's neat theories, and this mission is no exception.

The result relates to the composition of Mercury's surface rocks. Pretty much everything in the solar system, from the Sun down to little asteroids, formed from the same initial nebula of gas and dust. But all of these things have different proportions of the different chemical elements, and "cosmochemists" (a job title I love) try to parse those differences to understand the different formation histories of the star, planets, and other stuff, in order to tell the story of how the whole solar system came to be.

MESSENGER's Gamma-ray and Neutron Spectrometer (GRNS) can measure the composition of Mercury's surface rocks (within the top meter or so) from orbit, which is a pretty neat trick. The way this works, as explained by Larry Nittler in today's briefing, is that galactic cosmic rays come screaming into the planet; when they strike atomic nuclei, they produce high-energy ("fast") neutrons. These neutrons bump into other atomic nuclei, which emit gamma rays. The energy of the gamma ray that's emitted when fast neutrons bump into them is different for each type of element, so by mapping the different energies of gamma rays emitted by Mercury's surface, GRNS can develop a map of the distribution of chemical elements across the planet. This kind of experiment produces better results the longer a spacecraft is in orbit, so at this stage the results they have to report concern the most common elements in Mercury's uppermost crust. Here's a plot of those results, and how they compare to measurements on the other terrestrial planets: What's being plotted here is the ratio of the abundance of magnesium to the abundance of silicon on the horizontal axis, and the ratio of abundance of aluminum to the abundance of silicon on the vertical axis. Earth's mantle has a high magnesium-to-silicon ratio, representing its bulk composition. The Moon has a very high abundance of aluminum, a result of its history of having a global magma ocean in which aluminum-rich feldspar crystals floated to the top. Earth's basalts (black lava rock that covers most of the planet's ocean floors) formed from partial melting of mantle rocks, a process in which they get more aluminum- and less magnesium-rich. But Mercury's composition doesn't match the compositions of either lunar or Earth rocks, indicating that its geologic history is unique. Putting on my speculation hat here, I'm wondering if its composition reflects a higher degree of partial melting of its mantle rocks, or if its lavas came from mantle rocks that started out more magnesium-rich than what you find on Earth....

Another result from GRNS (not shown on this plot) overturns an observation made in previous flybys that itself had overturned an observation from Mariner 10. Mariner 10 results suggested that the surface of Mercury had a relatively low abundance of iron and titanium. But flyby data indicated otherwise. Now that MESSENGER's in orbit, they're reconfirming the Mariner 10 results. Nittler remarked that "this shows the power of orbital data versus flybys." He didn't offer an explanation for why the flyby data was discrepant.

Nittler also said that the GRNS data reveal that the surface of Mercury has a relatively high abundance of sulfur, up to a few percent by weight, which is at least ten times higher than that of Earth and the Moon. He said they don't know why this would be yet, though they speculate that it might relate to the explosive volcanic vents that MESSENGER has observed to dot Mercury's surface; explosive volcanism would be explosive because of the presence of gases including sulfur compounds in the lava. This high sulfur abundance is really important to people who are trying to figure out Mercury's formation history -- more on that in just a bit. First, let's look at potassium and thorium at Mercury.

Why care about potassium and thorium? Nittler explained: "The ratio of potassium to thorium has long been understood to be a very useful probe because potassium is a rather volatile element. It evaporates at relatively low temperature, and thorium does not. So this can provide information about the temperatures of processes in early solar system." He went on to say that the Moon has long been known to be strikingly different from the other terrestrial planets in that it is very depleted in potassium. This is one of the important observations that support the giant impact theory of the Moon's formation, in which the Moon would have been very very hot, and would have lost a lot of its volatile elements.

Nittler said that "Prior to MESSENGER, ideas about Mercury suggested that since it formed close to the Sun, Mercury should also have low potassium-thorium ratio." But just look at what GRNS has found: Nittler said, "Surprisingly, it's not low, it's as high or higher than the other terrestrial planets. It rules out some formation models, and it's consistent with the high abundance of sulfur and the presence of sodium in Mercury's exosphere. Taken together, [the presence of high abundances of] these elements are changing our view of the origin of Mercury. Mercury is not the Earth and it's not the Moon."

This may sound obvious, but it's kind of an important point. When we don't understand the geologic history of a place, we usually try to describe it by analogy to places that we have studied. Mercury looks kind of like the Moon but it's denser even than Earth, so its history has often been described as an amalgam of both. But it's its own world, with a history unique among the terrestrial planets.

In the Q and A session Nittler expanded on how these observations are upsetting previous ideas, which I did my best to jot down. "A number of models proposed after Mariner 10 indicated Mercury had an unusually large core. One idea is that it formed like Earth, then because the Sun went through a phase of extreme high intensity, Mercury was so close to this hot sun that the outer layers could have evaporated off. This would have predicted very low abundances of potassium and sodium and sulfur. Other models proposed that it formed from a specific kind of meteorite called CV chondrite that are very very rich in metal. For the most part these are not in detailed agreement with our observations, but variants cannot be ruled out. Another model is that Mercury formed larger and then after it formed an Earth or Moon-like crust, another planet hit it, smashing off the crust and outer mantle. At this point we cannot rule out this model. Some of our data are consistent with this model; whether high sulfur abundance is consistent, we have not yet figured out. There will probably be very many more models devised as we continue to get interesting data.">>
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by neufer » Thu Jun 16, 2011 9:22 pm

bystander wrote:Happy 16th Anniversary, APOD!

Thanks to Robert and Jerry for providing us 16 years of wonderful images and commentary!
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by NoelC » Thu Jun 16, 2011 11:28 pm

mattunes wrote:I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people
...
the images are just hideous
Oops, sorry.

-Noel

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by nstahl » Fri Jun 17, 2011 1:43 am

Yes, thank you guys (and gal(s?)) for several years of pleasure and education.

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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Beyond » Fri Jun 17, 2011 2:44 am

HEY, wheres the 'spacecake' and the star candles and the nebula 'crab-cakes' and the 'mars' bars and the rest of the 'party' stuff??
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by Beyond » Fri Jun 17, 2011 2:47 am

NoelC wrote:
mattunes wrote:I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people
...
the images are just hideous
Oops, sorry.

-Noel
Hey, NICE moon, Noel!! :D
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by neufer » Fri Jun 17, 2011 2:48 am

NoelC wrote:
mattunes wrote:
I sure hope the false color fetish doesn't spread from the Hubble crowd to the planetary people
...
the images are just hideous
Oops, sorry. -Noel
Click to play embedded YouTube video.
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Re: APOD: Mercury's Surface in Exaggerated Color (2011 Jun 1

Post by owlice » Fri Jun 17, 2011 4:01 am

Beyond wrote:HEY, wheres the 'spacecake' and the star candles and the nebula 'crab-cakes' and the 'mars' bars and the rest of the 'party' stuff??
I don't know where yours are, but our party stuff was cupcakes from Georgetown Cupcake. :-) Still have two left:
Image
Classic madagascar bourbon vanilla cupcake
baked with fresh raspberries topped with a white
chocolate buttercream frosting and a fondant flower
Image
Classic madagascar bourbon vanilla cupcake
with a whipped Callebaut chocolate frosting topped
with a fondant flower
They are out of this world. Which would you like?

Noel, that's a magnificent moon!
A closed mouth gathers no foot.