Dawn Captures Sharper Images of Ceres
“Craters and mysterious bright spots are beginning to pop out in the latest images of Ceres from NASA’s Dawn spacecraft. These images, taken Feb. 12 at a distance of 52,000 miles (83,000 kilometers) from the dwarf planet, pose intriguing questions for the science team to explore as the spacecraft nears its destination.”

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40 replies on “Getting Closer to Ceres”

  1. That’s one weird rock. There’s still no certain clues about the bright spots although I’m wondering if there is something in Ceres’s ‘soil’ that makes it reflect more brightly at some sun angles. Crystalline ices maybe?

    There is obviously a lot to learn about this world!

    1. I figured the white spots were areas where the underlying water ice was exposed by impacts (or possibly the underlying liquid water was exposed and then froze immediately after impacts, if Ceres has a liquid layer).

  2. Most of the craters look eroded, as though they are extremely old. The only sharp features are the few recent craters which appear extremely bright. Subsurface ice sounds reasonable to me, but if it was that pervasive and close to the surface, why isn’t it visible elsewhere?

    1. Most of the craters look eroded

      That could still just be an artefact of using the low res nav-cam, softening detail.

    2. Not to rain on anyone’s parade, but fresh craters usually look bright. Radiation causes a darkening of exposed material. So older surfaces tend to be dark, and newer surfaces tend to be bright. We need to wait for the spectra before talking about the possible composition of the surface.

      1. Case in point, the crater Tycho on the Moon. It’s a very bright southern-hemisphere crater, much younger than the surrounding terrain and much brighter. Age is relative, though, as it’s still around 108 million years old.

  3. If this is ice on Ceres. We need to set up a tanker train to Ceres launching tankers every year bringing back ice fuel to earth/moon orbit. How would you guys design such a system assuming Falcon H R tech or MCT R tech.

    Should arm be changed to setting up Ceres fuel mining operation first? Couldn’t Spacex make money fueling the inner solar system railroad soon?? Couldn’t this all be done roboticly??

    1. At the moment, it’s too far out to be useful. One day it would be useful for, say, colonising Ceres. Supplying local fuel both for the ships returning to Earth, and as a fuel stop for those expanding further out into the solar system. But we’re a long way short of that point in space settlement.

      1. The Ceres Run

        Using used Mars Colonial Transporters. Humans team with robots to fuel the Inner Solar System Railroad.

        A Miners Tale

        1. Elon Musk would laugh at the idea of a ‘used’ MCT. They are multi-use by design and necessity. I’m sure he’d be happy to sell you one, though.

      2. The gravity well of ceres is about 1/5 that of the moon, so Is the delta v from a high lunar orbit or lagrane point to Ceres more or less than the delta v from earth to the moon. Take a long slow trip, bringing the ice back to earth/moon L PT. Ceres is very cold, not a place for humans anyway. Bring that fuel closer. If large amounts of ice are on the surface, don’t you just need a robot lander that can land on the ice cut out a chunk maybe with lasers and bring it back? How would Robots mine Ceres???

        Mars sample return. Catch and play with an Astroid with SLS ? Hell bring fuel here instead.

        @dtarsgeorge

        1. Delta-v to Ceres is about 10km/s, same back.

          To put that in perspective, it’s around the same delta-v typically required for a launch from Earth’s surface into LEO.

        2. Maybe it’s more important to actually wait and study Ceres so that, among other things, the scientists can get an idea of how much ice/water is on Ceres.

          Grand plans are pointless without the science to justify them.

          1. We are waiting anyway Mr. Squared. Learning how practical it is or not to mine the asteroids doesn’t seem pointless to me.

          2. Nowhere did I say it was pointless to learn about the practicality of mining asteroids. That’s not even implied in my comments. That learning can be done without grandiose fantasies.

    2. The Martian colonists might have something to say about that. Ceres is a whole lot closer to them than to us.

  4. Those exceptionally bright white spots seem to have a lot of shadowing going on — i.e. the walls are steep – and deep … makes me wonder if something punched through the surface into an underground ocean …

    2. Ceres has a diffuse GH2O atmosphere. Could these be fresh frost layers around the vents that replenish it?

    3. This brightness is most likely an artifact. According to an exceptionally knowledgeable source on these images “The brightness of the spots are an artifact of stretching to enhance contrast. The albedo of Ceres overall is ~9%. The brightest spots at Hubble resolution were ~11%. As resolution gets better, some of the spots are unresolved, so their albedos increase.”

    4. Could Ceres reasonably still have an underground ocean? Considering its small size, distance from the Sun, and the lack of tidal heating from a large parent body (e.g. Europa/Jupiter), I would expect it to be frozen straight through.

      1. It would not be a liquid ocean or slush. It would be ice (and not necessarily all or some water ice) . However, a large impact would cause local melting (if in fact it is ice) which would flow and then re-harden (plus some sublimate or vaporize away.)

  5. Ice beneath regolith I’m guessing, with the ice (or water, quickly freezing as a surface liquid layer boils off) laid bare by impacts being covered up by regolith scattered overall from later impacts. Surely only ice could be so bright.

  6. Looks to me like a different bright layer with a dark , aged perhaps, covering. The center crater on the right image has a cone shape, with a slight darkness in the center. This may be some of the overlaying dark material. I thought ice at first, but ice would be level. Ice flows. Looking at the whole of both images, it looks like a dark crust. Not much of interest after waiting a long time to see what it looked like. There is the question of why some craters are white and some not. Obvious would be no light material. It would be rather deep to come up with why the white is not evenly distributed. Rather common. Strange that the scientists don’t give any theories. They are baiting us.Trying to keep up interests or saving it for papers. Ok, you found something interesting enough to comment on.

    1. “Baiting” us? Unlikely. The rational explanation is that the scientists are very likely waiting for Dawn to get much closer and to enter orbit so that they can have the high fidelity data from the spectrometer and the gramma ray and neutron detector that they require to fully establish or confirm their hypotheses.

      At the distance that Dawn is at now, the scientists are very likely only cataloguing interesting things for further study and posing interesting questions.

  7. Many small impacts have the effect of eroding the features of the larger impacts that are easy to see. Small impacts are far more numerous, but require much higher resolution on the imaging to detect.

    1. You can see that Dawn is coming in at a lower angle than the dead on Hubble image. You can see the same spot plus the dark “V” towards the bottom.

  10. Surely, though, that’s not equivalent since you can use SEP

    Very true, but most ion drives use a noble gas like Xenon or Argon, which are easier to ionise. These aren’t going to be readily available on Ceres. That means you can’t refuel your primary transportation system, which defeats the purpose of using Ceres as a fuel station…

    (If ion drives use hydrogen, they need to use more energy ionising the gas, which leaves less energy for the actual acceleration. The drive becomes much less efficient. Oxygen isn’t quite as bad for efficiency, but ionised oxygen is really bad for erosion.

    There’s an experimental ion drive called ELF (electrodeless Lorentz force thruster) which should be able to entrain a non-ionised gas to drastically increase drive efficiency and thrust density. That would allow you to use hydrogen (from water ice/methane/ammonia/whatever-you-find) as the primary propellant without having to ionise it. That would help a lot.)

  11. You can see the effect in this Apollo 17 panorama.
    Click on the image to expand it. And then click on the expanded image again to make it full size.
    Notice the rounded hills and generally soft dusty surface.After double expanding, you’ll need to scroll side to side to see the whole image, unless you have a widescreen.

  12. Beyond the destructive effects of 500 degree F temperature swings, heavy and light hyper-velocity ion flux, there is a multi-billion year bombardment of meteroids – like an unending machinegun firing into the ground into every square centimeter.
    On the Moon there is a pulverized layer about 10 or more meters thick.

    Here is an image of Becvar on the lunar farside. You see the old eroded big crater and some younger, more rugged small craters.

    http://the-moon.wikispaces….

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