More Mercury!

By Phil Plait | March 30, 2011 12:49 pm

NASA has just released more images of Mercury as seen by the MESSENGER spacecraft, and they’re pretty cool:

This first one is something of a repeat, showing the same region as the picture they released yesterday, but now it’s in color! Mercury is not exactly the most beautifully hued planet, but it does have some color to it. This composite was taken in the infrared (shown red in the image), red (shown as green in the image) and blue (shown as blue), and has a maximum resolution of about 2.7 kilometers (1.6 miles) per pixel. While most of the surface looks gray, look again: some of the craters do show subtle color variations. This is most likely due to the material excavated on impact — composition, particle size, and other factors change the way these features reflect light. This image only uses three colors, but the wide angle camera has eight 11 filters, which will allow planetary scientists to map the planet very effectively and learn about the composition and history of the surface.

Sometimes, the false colors really make a difference, like in this color close-up of a crater field near Hokusai. Funny — this image uses the same filters as in the first image above, but this region happens to have more color. That’s likely due to variation in mineral composition across the area, which is on average more diverse than in the much larger field of view above.

Anything white in the image reflects all light equally, but something blue means that the material absorbs redder light and reflects blue. Olivine (a very simple mineral found everywhere in the solar system), for example, behave that way, so we may be seeing an abundance of them in that one blue crater. Better, more detailed observations will make this clearer. Images like this show scientists where to follow up, with the crater’s color essentially announcing something interesting is going on there.

Of course, I do like the splashy, wide-angle shots too:

This shot of the horizon is simply lovely. You can see the long, linear rays from the crater Hokusai, which practically envelope the planet. Other fresh craters can be seen as well. Pictures like this from MESSENGER may become more rare as the science observations concentrate on high-resolution data, which means looking more toward "straight down" from the spacecraft’s viewpoint, as opposed to features farther away on the horizon.

But there’s a terrible beauty in all these pictures. Mercury is a strange little world. Hot, dense, battered, cracked… it’s as unlike Earth as any solid body can be, and it’s exactly those contrasts that will help us understand more about planetary geology and environments. We travel the solar system for many reasons — to learn about strange, new worlds; to discover new science; to have our brains tickled at the wonder and majesty of nature — but it’s funny how so many of these findings wind up helping us understand our own planet. That may not be the only reason we go, or even the most important one, but it’s still a fine thing to do.

Images credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington


Comments (39)

  1. We do these things “not because they are easy, but because they are hard.”

    …and also because they are COOL. Very, very cool.

  2. Kind of like watching It’s a Wonderful Life on a color TV.

  3. thetentman

    I don’t see any stars in the bottom image. Did NASA cook this up in a studio?

  4. Kalex

    thetentman: “I don’t see any stars in the bottom image. Did NASA cook this up in a studio?”

    No, this is common. The light reflecting from Mercury is too bright for the dimmer stars to be seen. It is like this in pretty much any picture of any planet.

  5. Daklok

    @thetentman: yes, they make the exact same mistake everytime they show a picture of an overexposed object.

  6. gkdada

    @Daklok and Kalex, I guess thetentman left out /joke tags. I don’t think he was serious.

  7. @8. I would assume.

    (I had previously meant to say *facepalm* but used brackets and the HTML editor ate my comment. 😛 )

  8. Dave

    For a point of reference, try looking at our Moon through a telescope, then look up at the sky. The eye that was looking through the telescope will be so light dazzled, it won’t be seeing any stars until it gets light adapted again.

  9. Sili

    When will we get to see those last few unimaged spots?

  10. DrBB

    Re the false-color image: makes it look like Mercury’s color scheme is basically that of a really nasty bruise.

  11. Guito

    What’s the blob between the impact craters in the last picture?

  12. Christopher Kandrat

    The picture is amazing, Mercury has been my favorite planet forever, but it looks like the moon to me, heh,

  13. Charlie Young

    Looks like they got a picture of Jesus on the left side there.

  14. jess tauber

    I don’t know about the rest of you, but I’m hoping to MINE the planet. Because its outer layers were stripped away (by impacts or radiation) the dense metal core is MUCH closer to the surface, and all that solar energy, properly concentrated by a giant mirror to the day and night sides, could both power extraction and processing as well as life support systems for any human miners on the planet, though I imagine most such things will be automated.

    Its not that I want to do this, my robot overlords are forcing my hand with their mind control. But we survive the best way we know how.

  15. nota bene

    Semi O/T….FYI there’s a connection between Debussy & Hokusai (the people, not the craters). Debussy famously insisted that any published edition of the score to La Mer feature Hokusai’s Great Wave as its cover. In the recording era, it’s often used as the album cover of Debussy pieces for the same reason.

    Skimming thru Wikipedia, astronomers obviously decided at some point that Mercurian (?) geological features would be named after artists, writers, musicians, etc. Very cool. I was previously unaware of this.

  16. Liath

    #13 Guito

    If you look very carefully at the blob you are referring to you can see that it is a 1930’s style cartoon drawing of a man’s head. I feel certain that Walt Disney got to Mercury before us.

  17. Messier Tidy Upper

    NASA has just released more images of Mercury as seen by the MESSENGER spacecraft, and they’re pretty cool:

    Don’t you mean hot? 😉

    Well I guess the Mercurian temperatures do range to both extremes! 😉

    Great news and images.

    [Obligatory] That’s no moon! [/Obligatory]
    (Can’t believe I’m the first to say that here.)

    … Even if it does look awfully Moon-like! 😉


    “A tin can placed on the sunlit side of Mercury or on the surface of Venus would melt.*”
    – Page 12, ‘Amazing Facts about Australia’s Southern Skies’, Steve Parish, Steve Parish Publishing Pty, no year listed.

  18. Messier Tidy Upper

    (Off-topic sorry, but hopefully of interest.)

    More Mercury is good – well info and images~wise anyhow – but on the sad news side of the equation seems there may be less “Earths” :

    Seems rare(r) Earth’s might be right after all. :-(

    On the positive side, they still estimate two billion Earth-like worlds are out there. :-)

    Frankly, it still jury out and insufficient info to really tell in my view.

  19. Amazing. We are literally watching history unfold as these high-res pics start to come in.

  20. Thameron

    “but it’s funny how so many of these findings wind up helping us understand our own planet. ”

    Such as? I like discovering things as much as the next guy (probably more), but I have always found this particular argument ludicrous. What could a interplanetary space probe tell us about our planet that an Earth orbiting satellite (combined with an enormous amount of data available to ground measurement) couldn’t?

  21. Deadtrinity

    I wonder if they could take a picture of the sun, I think its be awesome to see what it looks like that close up. 😀

  22. Messier Tidy Upper

    @ ^ Deadtrinity : Twould be even more awesome to watch what the Sun *does* in the Mercurian sky – but they’d a video rather than a still camera to record this :

    happening in reality rather than just animation. 😉

    (Mercury’s double sunrise and sun standing still. Posted this before but thought – hopefully correctly – it’s worth posting again now.)

    Also to celebrate these here’s the Mercurian planetary anthemn :

    for y’all. (Esp. classical music fans.) :-)

    Plus this bonus : Off topic but fascinating clip I stumbled on :

    ‘What If other planets replaced the moon? which doesn’t feature Mercury but does “star” some other “wandering stars” in our night sky in perspective of sorts. 😉

  23. jeremy greenwood

    Debussy is about the size of Greater London, with the disturbed area around it the size of South East England, and the rays would be splashing against the Alps right? Have I got the correct scale here?

  24. Messier Tidy Upper

    Additional link for y’all here :–23_AW0&feature=related

    which does “star” the relevant planet – & the latest images.

    Plus this short but reasonable news item :

    On the MESSENGER’s arrival bearing photographs.

    As well as this :

    Mercurian if not mercurial clip by Sixty Symbols. :-)


    “The Ramans do everything in threes.”
    – Arthur C. Clarke, ‘Rendezvous with Rama’, Final page (252), Pan
    Books Ltd, 1973.

  25. Nigel Depledge

    @ Thameron (23) –
    For example, how the planets formed.

  26. #18 nota bene:
    The IAU has established naming conventions for features on all Solar System solid bodies; each body has its own set of conventions. As you rightly observe, the convention for craters on Mercury is to name them after artists, musicians and writers. Not all geological features – just the craters. There are other conventions for its other features; plains are named with the names of Mercury itself in various languages, valleys are named after radio telescopes ( e.g. Arecibo Vallis, Goldstone Vallis ) ( because Mercury’s rotation period was first measured by radar ), and scarps and ridges are named after famous ships of discovery ( e.g. Santa Maria Rupes, Endeavour Rupes ).
    The reason for the crater naming convention is quite simple. When people first began mapping the Moon in the 17th Century, the convention was established of naming craters after astronomers and other scientists. This trend was later continued on Mars, naming them after scientists who contributed to the study of that planet. As for Mercury; Mercury the god, as well as being the messenger of the gods, was said to be a great musician – hence while the Moon and Mars are a roll of honour for scientists, it was decided that Mercury would become one for music and the arts.
    Other conventions are followed on other planets and satellites; e.g. on Venus, for obvious reasons, the craters are named after famous women who contributed to human culture.

  27. Anchor

    24. Deadtrinity:

    The Sun from Earth subtends about a half degree. At Mercury’s average distance from the Sun, it would be appear “only” about 2.4 times larger, or around 1.2 degrees across. Believe it or not, the Sun (and our Moon) seen in our skies is like the width of a pencil eraser as seen from arm’s length (about 2 feet from your eye). In order to appreciate how large the Sun is (on average) as seen from Mercury, hold a common half-inch marble at arm’s length.

    By comparison to some “Hot Jupiter”-type exoplanets that have been discovered, our Mercury is as ‘distant and cold’ as the rest of the terrestrial planets in our system. In fact, it may possiblyturn out to be something of an anomaly that our Solar System doesn’t have a planet interior to Mercury’s orbit…but that may not necessarily mean there wasn’t one there that had been consumed by the Sun sometime in the 4.6 billion years since our system’s formation…

  28. Anchor

    Consider: if the Sun consumed something like a large planet (let alone anything like the equivalent of a ‘Hot Jupiter’ – a class of object that has only recently been found to be so commonly associated with planet-bearing stars) early on in our Solar System’s history, it is at least conceivable that the resulting disruption can have blown away the primordial atmospheres of what we currently call ‘terrestrial planets’, ours included.

    However implausible it may seem in the light of current consensus, the possibility exists – within our current knowledge or uncertainty – that almost all large planetary bodies which grow from a protoplanetary disk may ROUTINELY acquire a primordial atmosphere directly from the protoplanetary disk…and become ‘gas giants’ as a normal course of events. Nobody yet knows what the ‘typical’ planet-growing’ recipe involves, and from what little we actually do know it is still possible that the conventional and currently established scenario for how solid particles in a gaseous medium like the protoplanetary disk gather together via gravitational and electrostatic forces into growing planetesimals to do their growing thing holds considerable weight. But maybe that’s not all there is to it. Maybe there’s more to it and it’s fiendishly complicated, but maybe it’s SIMPLER than we think. Nobody yet knows.

    It may not be all that complicated a problem. While we have an abundance of knowledge about basic forces that must be involved, we still do not know precisely in detail how planets form.

    But we do know enough to appreciate that catastrophic events can drastically change the game. Suppose almost ALL planets that grow fast and acheive a certain mass TYPICALLY hang on to their primordial atmospheres, just like we currently think Jupiter and Saturn and Uranus and Neptune have: what would THOSE planets look like if the bulk of their thick and deep-soupy atmospheres were catastrophically ripped away to expose their cores?

    Mercury, being nearest to the Sun and curiously also plying the most eccentric orbit of any planet (unless one discounts Pluto in that category) no doubt harbors secrets to the formation of our planetary system. Messenger will inevitably uncover some of them. The wild and (I admit disconcerting!) possible scenario I’ve outlined above may be ruled out by the science that comes from this mission (whew!). On the other hand, we can’t ever afford to ignore new and potentially shattering possibilities simply because they may not square with our preciously adopted current beliefs: a ‘belief’ is a canard that is just about as important as worrying about what hat you prefer to wear. If anybody wants genuinely to think scientifically, they have abstained utterly from the tyrrany of fashion, in favor of something that demonstrably and ACTUALLY WORKS to keep their head warm.

  29. Nigel Depledge

    Anchor (31) said:

    Suppose almost ALL planets that grow fast and acheive a certain mass TYPICALLY hang on to their primordial atmospheres, just like we currently think Jupiter and Saturn and Uranus and Neptune have: what would THOSE planets look like if the bulk of their thick and deep-soupy atmospheres were catastrophically ripped away to expose their cores?

    Well, if I’ve understood the current ideas about how they formed, without (the bulk of) their atmospheres they might look rather like Mercury. Or Earth.

  30. DrBB

    @31 Anchor:

    What a cool and (AFAIK) plausible speculation. Instead of being bizarre anomalies, the hot Jupiters we keep finding end up being the norm and we’re the exception, due to a catastrophic crash-and-blast of one such beast earlier in the history of Sol system. Caveats notwithstanding, I love it!

    Re beliefs, since nothing’s at stake for me either way this is the hat I’m gonna wear for now until somebody proves it untenable. Thanks for posting it!

  31. Joseph G

    I wonder if there actually is a significant amount of mercury on Mercury (being a heavy metal and Mercury being a dense little bugger).
    For that matter, I wonder if there’s Uranium on Uranus, Neptunium on Neptune, or Plutonium on Pluto?
    Quick, someone name one of the KBOs “Unobtainus”!

  32. Joseph G

    @18 Nota Bene: Fascinating stuff about Debussy and Hokusai! I never knew that. I’ve always liked ukiyo-e paintings, and Japanese art in general, and I’d never heard of that connection.

    @17 Jess Tauber: The only problem is the high delta-V needed to get goodies back from Mercury. But I guess with all that solar power, you can just build some huge frickin’ mass drivers 😀
    I’ve actually wondered about that – other then photovoltaic power, would it be hard to set up a solar power system on Mercury? I’m thinking of a more efficient heat-engine kind of thing, like those solar towers with steam generators. I was wondering if it’d be possible to economically cool something like that, the days being so long there and there being no substantial atmosphere to carry away heat? Heat engines don’ work if the whole darn thing is really hot 😛

    @34 DrBB: That is an intriguing idea. I kinda hope it’s wrong, as I’m a hopeless romantic when it comes to colonizing other star systems. I always just assumed that hot Jupiters were by far the easiest to find using current planet-finding methods (both radial velocity and transit methods, at least). The transit method one is particularly infuriating, due to the small odds of a star’s ecliptic being aligned with our point of view enough to use that method. I’ve seen estimates that for every terrestrial planet we find using the transit method, there are about 50 that we miss!

  33. icemith

    So, let me get this up to date…… Mercury is now right in fashion :- Green is the new Red! (At least blue is still Blue).

    @35. Joseph G: You forgot to wonder if there was any earth on Earth.


  34. Gary Ansorge

    Ah, Mercury, a big, little planet, full of resources we can use. Mass drivers on the equator, powered by the sun, to launch refined metals to our neck of the sol system. I expect it would take quite a few millennia to use it all up.

    We may not be the only species to think of this:

    Space miners wanted; Short hours; good pay. 18 month labor contracts required. Please apply at your local Mercurian Mining Development Corporation headquarters.

    Gary 7


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