Fans of Ceres will find this article interesting.

The 200 Plus Images are something I would love to get my hands on. Rotation animation Anyone!?


http://www.space.com/scienceastronomy/0509...res_planet.html

HST raw images tend to eventually end up on the query-able release site... it depends on what is proprietary and for how long... I made a color composite from HST Ceres images as far back as '97.

Have you posted those yet? I would love to add that to my Ceres archive.

Interesting images. I've been comparing them with earlier telescopic images. The bright spot is definitely something new. It seems to me that Ceres is divided into lighter and darker colored halves, though the boundary is more irregular than the one on Iapetus (and the albedo differences are not so great). "Piazzi", presumed to be a crater, is a dark circular or oval formation somewhat more than half surrounded by lighter "arms" or lobes. I believe this formation is observable in the new pictures as well (though possibly it is simply a similar formation located on the opposite side of Ceres from the older images). In any case, the very bright spot is located approximately in the center of the light hemisphere and is definitely not seen on the older images. Possibly the region in which it occurs was not previously imaged, but I do not think so. I am wondering whether Ceres may, through some strange mechanism, be active. Enceladus is smaller, and yet turns out to be far more interesting than expected. Might not Ceres be more than an inert lump of ice and rock? Even if it turns out that Ceres is inactive, the composition of the bright spot should be very interesting.

Ceres has long been suspected to be more than a totally undifferentiated ball of hydrated silicates. It's further out in the belt where things with water of hydration in minerals start to show up and S-types are declining or low in abundance, I can't recall if it has some in the infrared spectrum... stuff like Serpentine type minerals (hydrated olivine/pyroxene)

It continues to be astonishing how un-battered it looks. Pretty smooth circular limb and no obvious gouges and big-mother craters as it rotates. A planetino indeed!

We've been all hot about Vesta for years, with it's basaltic spectrum and probable pieces in meteorite collections, but what about the other "Big 2".. Juno and Pallas. One or both has very non-usual specta, not all that similar to other asteroids, though nothign really spectacularly unusual like Vesta. Juno, I think is in a very high inclination orbit.

Hubble Press Release Images: Largest Asteroid May Be 'Mini Planet' with Water Ice

http://hubblesite.org/newscenter/newsdesk/.../2005/27/image/

Looky Looky a great animation of Ceres rotation!

http://hubblesite.org/newscenter/newsdesk/...2005/27/video/a


I wonder how image stacking would help bring out more detail on Ceres.


EDIT: Opps! SigurRosFan Beat me to it.

Well, a body of its size is easily spherical, and with Hubble's resolution not much is visible anyway. It could be saturated with smaller craters.



No, it's Pallas which has very inclined orbit. Juno is by far the smallest and the most irregular of the first four asteroids.

Unfortunately, I'm pretty sure this animation is *not* a series of Hubble images, but rather a simulation based on a surface map based on Hubble images. So its of no use. You need to get the original images to work with.

So, it's relatively obvious that the largest of the main-belt asteroids (Ceres, Vesta, Pallas) are differentiated objects. My curiosity is whether or not these objects must have differentiated "in place," in other words, only in the context of their current mass, size and position.

Could they have once been part of a larger differentiated body that was destroyed by a massive impact? I guess we need a lot more data about the large asteroids, but I'm wondering how small a body can be and still undergo differentiation. When you consider that the Moon apparently is still predominantly made up of undifferentiated chondritic material, sandwiched between a once-molten core and a differentiated mantle and crust, we know that a Moon-sized body does not completely differentiate... and we also suspect that the Moon was formed by a giant impact which completely destroyed a Mars-sized body (which would have to have contained a lot of chondritic material for the Moon to contain a lot of it), so 1) the Mars-sized impactor must not have completely differentiated, and 2) lunar differentiation may not fit into a model of differentiation for primarily-accreted bodies.

Ceres lander/orbiter mission, anyone?

-the other Doug

Indeed -> DAWN mission to Ceres/Vista

Eric P / MizarKey

Basic data of the Dawn mission:

Launch - June 17, 2006

Vesta arrival - October 2011

Ceres arrival - August 2015

Killing the magentometer seems like a particularly bad idea right now....

That's the Good Old Theory, isn't it? I seem to recall that the "original fifth planet" played a role in some of the rollicking old space operas of the '40s and '50s. Then it was decided that any possible planet, even with the mass of the whole Main Belt, would have been pulled apart by Jupiter before it could ever form.
I'm not sure how reliable my logic on this is, but it seems to me that if Ceres is still spherical, it would have had to have formed in situ rather than as a result of a collision -- I don't think it's so big that, if it originated as an irregular fragment of a larger body, it would necessarily pull itself back into a sphere; compare the much larger Iapetus, which was evidently badly knocked about earlier in its history, and still shows the evident signs. Still, I suppose DAWN will tell us a lot more about Ceres' history; unfortunately we'll have to wait a long time for DAWN to get there!
Perhaps MER and Cassini will keep going long enough to keep me from getting bored. Ideally I'd like these missions to overlap enough that there will always be images coming back from some corner of the Solar System!

I recall an illustrated story from a late 1970s graphic SF magazine about two astronauts who come upon a large smooth black sphere in the Planetoid Belt.

They can't figure out what it is and toss around all kinds of theories, until one of them thinks it may be the core of what was left of a gas giant planet that was somehow destroyed ages ago. They come to this conclusion just as the laser drill they placed on the black ball's surface starts cutting through....

If this was done like previous sets for targets that appear so small, the 200 images are probably sets of 50 at each of the four viewpoints shown in the image released possibly using different filters (but not always) and almost certainly multiple views at some or all wavelengths for a super-resolution effect. So the only way to make a movie would be to do what they did, or to make a four image animated gif, which could be done with what we have.

I can't believe the length of this mission.


Hardware failure possibilities goes up the longer the mission. What happens if something bad happens a week before Dawn arrives (*Knock On Wood*)??

I must say I found this article to be quite an eye-opener. I always thought of 'roids as boring lumps of rock, not this interesting! I wish ESA could launch a Ceres Express!

The good thing that may come from this, according to what I have read, is that there may be multiple flybys of smaller asteroids along the way and in between the main targets.

There are currently three orbiters at Mars with one more cruising there now. In the meantime, Messenger will have flybys and a main mission returning images from much of the period between now and 2011, and Venus Express will have its mission in the meantime. Who knows how long Mars Smart Lander will last? And New Horizons will provide a quick flyby of the jovian system in 2007 before getting to Pluto in 2015. The Moon is sure to get still more attention (SMART is there now) from multiple countries by 2015. And a few small body missions are on the way.

Cassini may last decades, trumping all of this with a vast set of targets that will provide many discovery opportunities before we would become bored with the saturnian system.

The MERs won't last forever (moving parts are hell), but if left to stand and collect sunlight, with the occasional serendipitous cleaning event, they could last indefinitely, although their use will taper off if they lose mobility before something else gets them.

I'm wondering...

If Ceres is differentiated into a rocky core and water-ice mantle with a dirt-layer on top...

Since it's closer to the sun, it's warmer inside than Callisto. Temperature is relatively high since the dirt is black.

The water ice, protected from 4 1/2 billion years of sunlight <more or less> by thickness and a dirt-layer, may be pretty damn soft, especially if small amounts of salts are present, leached out of the rock as it differentiated.

Ceres may not preserve craters ... even with low isotope heating and heat flow from inside, the ice may be so warm and soft that even in the low gravity, it just flows, turning craters into palimpsests, like craters on Enceladus, Ganymede and Callisto are relaxed. Very very interesting....

Back in August 2003:

--- Ceres apparently retains considerable volatile material. The latest gross properties indicate that Ceres has a density of about 2100 kilograms per cubic meter, suggesting that the body's composition may be half water (). Its density is similar to that of Ganymede (1940 kg/m3) and Callisto (1860 kg/m3). ---

http://www-ssc.igpp.ucla.edu/dawn/newslett..._evolution.html

Was it pure happenstance that Juno was the third asteroid discovered? It's only the thirteenth or fourteenth largest Main Belt asteroid, it's not particularly bright, and I can't really see that there's anything remarkable about it; why was it discovered before. say, Hebe, Iris, or Hygiea?

This article shows a limb profile.

HST Mapping of the Shape and Rotation Pole of Ceres

http://www-ssc.igpp.ucla.edu/dawn/newslett...df/20040831.pdf

Great Links Everyone! I'm also looking forward to next earth telescopes that will become operational over the next 10yrs. That way Ceres mapping will improve and help with the dawn mission.

I really do hope Ceres has more in common with the Jupiter moons.

One big advantage of Ceres is that the opportunity for getting there repeats every 15.5 months - more often than Mars. Meanwhile the Hohmann flight time is about 470 days - not seriously worse than Mars. Indeed, it's almost weird that the asteroids haven't been better covered by missions before the ion-age. After all, it's still bright out there - a couple of hundred watts per square metre - and the low local gravities mean that multiple targets becomes an attractive option. Or is it all too O'Neillian? Finding accessible and potentially useful resources just a few thousand m/s of delta-V from cislunar space?

Andy G

I agree that it is strange that we haven't already made more missions to these places, but hey, we've only launched a few probes per year that escape Earth orbit, and that seems to be the budget. What an interesting coincidence that this giant water resource is already named after the Earth goddess.

Huh. So as late as 2011 or 2012 we could launch a "Ceres Express" probe, and it would get to Ceres before DAWN?

David:

True, but... ...half the story.

Firstly, 'Ceres Express' wouldn't visit Vesta as well. Secondly, it might not be able to orbit Ceres except at great expense in terms of launch mass. And thirdly, it ain't funded!

Have a look at the attached trajectory diagram - in effect, Dawn carries out two missions for the price of one - and orbit insertion around two mini-planets, as well!

The asteroid size comparisons are also fascinating! These are *worlds*!

Bob Shaw

It's funny that at about the same time we find ourselves talking about how small Pluto is, and how big Ceres is.

Originally they called Ceres a planet and then demoted it for being too small. I always wonder if it had tipped the other way, and everything not a comet orbiting the sun was called a planet. It would have made the way the solar system is presented in school unrecognizable, but given the fact that there is apparently no great size gap that we once thought existed, it might actually have been a more realistic conception of our solar system than the one we were taught with nine planets neatly orbiting the sun.

Check out this version of the rotation movie. It is much more natural.

http://www.swri.org/press/2005/Images/ceres_movie.html

http://www.swri.org/press/2005/ceres.htm

I wonder if we are missing any other potential internal heating mechanisms possible besides tidal flexing and radioactive decay which could create a liquid ocean on small ice worlds like this......can't think of any though...

When the bright spot is near the right limb it appears to be the central peak of a crater. A patch of ice poking through the darker crust perhaps?

Nice link tedstryk!

Its intresting to see so much detail on such a small body.

Its three different gif animations for the three frequency bands, and so the rotation for the three version may not be syncronised, its rather unlikely it will be in fact.

--- Its density is similar to that of Ganymede (1940 kg/m3) and Callisto (1860 kg/m3). ---

Ceres: The missing fifth galilean moon??

http://xs45.xs.to/pics/05360/Ceres_Jupiter_System.gif

Wow, that makes Ceres look puny.

Without wishing to labour the point, the Galilean moons *are* planets! Well, they would be if they were anywhere other than orbiting Jupiter (unless they were in the Kuiper Belt, when of course they'd be, er, you know, thingies. Wossernames...). And Ceres is a mini-planet at best...

Proto Planet

Thus, Ceres is a mini-planet or a "embryonic planet"?

And the layered jupiter moons are capture-planets.

p.s. Er, what is a planet??

Shhsh! If I tell you that, I must kill you...

...

Are there specifications for the maximal thickness of Ceres' ice layer somewhere?

This all makes me wonder...Is Vesta, being basaltic, part of the core/mantle of a destroyed planet in the asteroid belt, and is Ceres the largest attempted planet, with similar ratios to proto-Vesta, not to be destroyed. It would indeed be cool to find out that Ceres was an ejected galilean moon. But it is hard for me to see how it ended up in its current orbit in such a case.

Bob: The idea that the galileans are planets is an interesting idea....I have always thought that it would be a cool idea to define planet as worlds large enough to be reasonably spherical (nonwithstanding elongation from ultra-fast rotation) and possible sustain internal activity (maybe Enceladus be around the cutoff there). Otherwise I support abandoning the term. Many suggest keeping it narrow despite the lack of a cut off so that we have a reasonable number of planets to teach schoolchildren. I say that we can't define the solar system's nature based on what would be easier for school children, because this is, in actuality, giving the children a severely distorted view of the solar system, not a better one.

If -- as suggested in the press release -- Ceres may be as much as 25% water ice, then the ice layer would be about 10% as deep as Ceres' total radius.

Has anyone noticed what an attractive living place Ceres starts to look like? Brimming over with easily accessible water and organic compounds; nice low gravity, making landings and takeoffs easier; far enough from the Sun that the intensity of solar radiation outbursts is considerably weakened (and water ice makes a good shield against that in any case)... maybe it's time to consider buying real estate there.

I'm sold! Where do I pick up my tickets??!

I've been saying for a while that the asteroids are the logical next place for humans to visit. They're pieces of the ancient accretion phase of the solar system and hence scientifically interesting, and they also offer literally tons of resources that make them far more exploitable than smelly, rusty, salty old Mars down there at the bottom of that gravity well.

Does anyone have the stat for the surface gravity of Ceres? If it's enough that you could firmly root heavy machinery without extreme measures, I think we may have a winner there...

-the other Doug

wikipedia lists it as 0.27 m/s^2

Divide Earth weights by 36 and you'll have approximately the correct number. An M-1 tank (by way of example) would weigh 1750 kg (about 4000 pounds) on Ceres. So no, you couldn't imitate Superman and lift a tank one-handed... but maybe a gang of Cereans drunk on Vestan ale could tip one over after a night of carousing.