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This is the picture of Vesta, which is an object in our solar system:


That’s the picture that Wikipedia uses as of this writing, and it was taken by the Hubble. The key thing to note is that Vesta, which lies in the asteroid belt and has been thought of as a big asteroid, is very globular like a planet. This is unusual for an asteroid.

This is a picture of Vesta as conceptualized by NASA scientists. It is a model, not a photograph.


Model of Vesta This image shows a model of the protoplanet Vesta, using scientists’ best guess to date of what the surface of the protoplanet might look like. It was created as part of an exercise for NASA’s Dawn mission involving mission planners at NASA’s Jet Propulsion Laboratory and science team members at the Planetary Science Institute in Tuscon, Ariz. Other resolutions, desktop images here. Click the image to embiggen.

The images incorporate the best data on dimples and bulges of the protoplanet Vesta from ground-based telescopes and NASA’s Hubble Space Telescope. The cratering and small-scale surface variations are computer-generated, based on the patterns seen on the Earth’s moon, an inner solar system object with a surface appearance that may be similar to Vesta.

Vesta makes up about 9% of the entire asteroid belt. In fact, if you take the largest handful of objects in the asteroid belt, Ceres (that’s the largest), Vesta, Pallas and 10 Hygiea, you’ve got half of the mass of the entire thing, according to the most current estimates. This sort of thing makes one wonder if some or all of these objects should be thought of as something other than asteroids. And this is a question that has been raised in relation to NASA’s Dawn project.

“I don’t think Vesta should be called an asteroid,” said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. “Not only is Vesta so much larger, but it’s an evolved object, unlike most things we call asteroids.”

The layered structure of Vesta (core, mantle and crust) is the key trait that makes Vesta more like planets such as Earth, Venus and Mars than the other asteroids, McCord said. Like the planets, Vesta had sufficient radioactive material inside when it coalesced, releasing heat that melted rock and enabled lighter layers to float to the outside. Scientists call this process differentiation.

McCord and colleagues were the first to discover that Vesta was likely differentiated when special detectors on their telescopes in 1972 picked up the signature of basalt. That meant that the body had to have melted at one time.

Special sensors. I gotta get one of those.

Anyway, this July, the Dawn Space Robot will approach Vesta and spend about a year in the vicinity. We’ll see how close that model is, and hopefully, Wikipedia can get a better portrait of the protoplanet/minorplanet/asteroid!

More details on the project are here.

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46 thoughts on “Vesta

  1. Wasn’t that Asimov? (but their writing styles have similarities) Anyway, early short stories by authors that later got famous are best glossed over.

    We have another dwarf planet (which accidentally got trapped in orbit while its binary companion got ejected): Triton, currently on a retrograde orbot around Neptune and with a diameter of 3000 km.

    There are probably dozens of dwarf planets bigger than Triton hidden in the “scattered disc” component of the Kuiper/Edgeworth belt.

  2. Yep, it was Asimov.

    And contra Birger, I think the writers of the ‘golden age’ of science fiction – Asimov and Heinlein especially – all did their best work in their early short stories. Even L. Ron Hubbard wrote some good short SF before he went off the deep end.

    At any rate, this project looks fascinating. Next up, asteroid mining!

  3. Well it is already well-established that sufficiently large objects end up getting gravitationally rounded, and become subject to differentiation processes to some degree (the qualifier because there are some large gravitationally-rounded objects which appear to have been incompletely differentiated, e.g. Callisto).

    Turns out the maximum size of objects in the asteroid belt is roughly at the point where gravitational rounding/differentiation occurs, so there are only a handful of objects which show signs of this. In the outer solar system (Kuiper Belt, scattered disc) there are many examples of large, gravitationally-rounded objects: the masses are higher thanks to the slower dynamical timescale and there is more ice in the composition, which is weaker than rock.

    As for the large mass fraction in the largest objects, I’d guess this kind of thing is expected from the accretion process which is affected by positive feedback: large objects are better at attracting more material. In any case, none of them outmass the rest of the belt, unlike the major planets which significantly outmass everything else in the vicinity.

    (But hey, attempting to get the target object reclassified as some new category of object is a nice easy way to try and make your mission more interesting to the media than if it is just trying to study one of a zillion asteroids…)

  4. Well, as an aspiring writer of sci-fi and fantasy, I’d appreciate it if you wouldn’t ‘gloss over’ the short stories that are giving me traction in the industry. These are the stories that are going through the slush pile, they have to compete against hundreds of other stories for attention. If they survive long enough to float to the surface, they have to be pretty darn good.

  5. I’m sorry, F, I tried to use small to medium sized words in common usage throughout the English speaking world, but clearly I’ve failed. What particular part of my post is giving you trouble, big boy?

  6. And someone who had “done the due dilligence” of rereading his own post probably could have figured out the problem before sighting the snark gun on a potential reader. (What do they teach the kids about self-promotion these days?)

  7. I did, thank you. The snark gun was properly aimed and utilized.

    Incidentally, they teach the kids that no exposure is bad exposure, and that people tend to prefer someone who is genuine. I genuinely have little patience for the rude and dimwitted, hence the reply.

  8. Back in the vicinity of the original topic, has there been any work done to estimate how many moons are locally formed bodies, (our own moon, for example) and how many may have formed as proto-planets only to be captured later, (such as the Triton theory)?

  9. Writers, said the science fiction author Isaac Asimov, fall into two groups: “Those who bleed copiously and visibly at any bad review, and those who bleed copiously and secretly at any bad review.”

    Actually, when it comes to discussing your own writing, there is zero upside to being an ass. As Jacqueline Howett has learned (as a few select did before her), all it does is make you look unprofessional enough to forget the first rule of holes and invite people to find and highlight the flaws that any writer has.

    You, for example, don’t appear to keep track of what you’ve already written. “What particular part of my post…?” followed by “Fair enough” when answered doesn’t give much support to the idea that you did the “due diligence” you claim. So now you simply look like someone who’s willing to be less than honest rather than gracefully take a teeny, tiny ding to the ego.

    You see how this isn’t a win for you?

    That first rule, by the way, is “Stop digging.”

  10. We aren’t discussing my writing, are we? I don’t think the NYT writes reviews, bad or otherwise, on the topic of chat board posts. If you would like to write a scathing review of one of my stories, by all means do so. Then your observations about how writers respond to bad reviews will have some relevancy.

    And Steph, less, than honest? I am many things, but less than honest isn’t among them. If anything, it is an overabundance of honesty that is my problem. Anyone who read the thread up to that point and possessed even rudimentary skills of deduction would have no trouble, at all, figuring out for themselves who my post was intended for.

    F decided to act like an ass, and earned the reply he got for that decision. You are beginning to invite the same. If there is a hole, it is of your creation, the dirt is by your feet, and the shovel is in your hands. I invite you to abide by your own unsolicited advice and place it on the ground.

  11. This is not a chat board!!!!! I is a blog!!!!

    Not that that matters.

    OK, everybody, back to your writing! I want to see five pages by the end of the day!

  12. Yup. BTW, it’s Patrick, or Pat. Patty is a girl’s name. I may have shortened your name, but I didn’t deliberately change it in a way that attacks your gender identity, making your retaliation look rather immature and petty.

    As I said, stop digging.

  13. Actually, Patty is used for both men and women and was originally a short version of Patrick. Like many names (Jordan, Lindsey), adoption as a feminine name has decreased its popularity as a boy’s name, but it is still recognized as one:

    By the way, adopting the diminutive form of an opponent’s name in the middle of argument is a gendered behavior. Of the dozens of people who have done it to me, only one has been female.

    Nice attempt to distract from the fact that you showed up telling us not to underrate your writing and now want to say no one was talking about your writing, though.

  14. Yes, and Leslie used to be a boy’s name. But since we don’t actually live in that century…

    And no, I didn’t ask people to underestime my writing. I was using my writing as an example of the reasons you might not want to dismiss short stories

  15. Two weeks after St. Patty’s Day, and you claim I’m attacking your gender identity, despite my providing documentation that it’s still considered a boy’s name. Then you erase Leslie Neilsen, who died well into this century. Look, if you’re going to work that hard to get offended over diminutives of your name (and the idea that you share a form of your name with girls, eek!), perhaps you should stay away from the diminutive forms of other people’s names. That’s what happens when you start digging.

    No, you didn’t just use your writing as a counterexample for why people should pay attention to short stories. You used it as a counterexample of why people should pay attention to “early short stories by authors that later got famous,” unless you didn’t do the “due diligence” to determine that they were what Birger was talking about before you objected to his(?) comment. And even if you had wanted to talk about why people should pay attention to short stories, there are one or two out there by other people that you could have cited.

    Instead, you brought up your own writing, in a poorly written comment. Then you got pissy when you were called on it. Then you proceeded to say a bunch of stupid, inconsistent stuff while working to justify being pissy. So now we all know that you’re aggressively defensive and you don’t pay a lot of attention to continuity. Exactly what attracts people to a writer, yah?

    Where is that upside you were talking about?

  16. You know, Steph, you are amazing. Truly. You see, you made the claim that acting like a ass is of no benefit, and is detrimental to one’s aspirations. You have since proceeded to act like a total and complete ass. Aggressive, insulting, and more than a trifle pedantic. You must have the last word, it would appear. And you are welcome to it, although it won’t make your claims of the superiority of civility any more consistent with your demonstrated behavior.

    As for me, I said early that being genuine was more appealing to most people than artificial civility. I don’t have a Asimov quote to give you, but then Asimov never had to deal with Facebook and Twitter. What I do have are several bits of actual evidence, which this being Science Blogs, I think might carry more weight than your anecdote.

    First is a study that appeared in the New Scientist a while back:

    Secondly, a quick glance at my website stats for the last month shows that traffic went up nearly 130% above mean since you decided to make a federal case out of this. My FB page has also seen new ‘likes’ since Friday at a rate noticeably above average.

    Lastly, a project I’m involved in jumped over 20,000 slots on Amazon’s ebook rankings. Which is nice, because that means I have some money coming. Now, I cannot independently verify that this jump was a direct result of your little crusade, but it’s a hard coincidence to ignore.

    That’s the upside. Now, I didn’t want this to become about me. I wanted to defend the work of all aspiring writers, including you, from the apathy I saw in Birger’s post. You, otoh, want to talk about me, which is flattering, but I think we’ve taken up quite enough of Greg’s bandwidth with it.

    If you wish to continue, please feel free to contact me directly.

  17. OFFS, Patrick, you know that the numbers you’re bragging about are easy to find if I want to, right? If they’re small, bringing them up here isn’t going to make you look any better. Just smaller.

    You want something like this to not be about you? Start with:

    Birger, fame doesn’t necessarily reflect an author’s best work, and it can actually stifle their creativity. The fear of losing audience (or the pressure from publishers to maintain it) can lead to some terribly formulaic writing. John D. MacDonald did his most creative work in his early short fiction. And some authors get too popular to be edited, which means that their early work generally outshines their later work. Take Mercedes Lackey, for instance. The Tarma and Kethry short stories, edited by notorious stickler Marion Zimmer Bradley, are what bought Lackey’s fame. You’re much better off reading those than anything recent.

    If you dislike “pedantry” (aka explanations), you might want to try being polite and correct in conversations where you suggest the “rude and dimwitted” don’t deserve any patience. For example, what I actually said was “Actually, when it comes to discussing your own writing, there is zero upside to being an ass.”

    By the way, Greg, writing nearly done. Not five pages, but not horrid for coming off eight straight days of work.

  18. Greg, do you really want to give me free advertising after the above?

    I didn’t wish to derail your thread, as I really like the subject and have been following the Dawn mission, (I used Ceres as a location in a yet-to-be-published novel). But I don’t shy from confrontation either.

  19. Well, I guess that answered my question. Yes, it’s the Crimson Pact. I am only one of two dozen authors, some of which are much more accomplished than I. It’s a neat premise and a good way to tie together a wide range of genres. Not that I’m an impartial judge, but it’s fun stuff.

  20. Greg, I forgot to mention that you met Kelly Swails (one of the other writers in that anthology) at the super-secret GoH party at CONvergence two years ago. She was the blond woman from Chicago sitting on the couch, aka Kelly X.

  21. If it is not an asteroid..and not a planet..what is it then?
    A planeroid or something. How big is this planet/asteroid anyway?

  22. @ Pat #15

    Thanks for your concern over ease of reading for us illiterate types.

    To be more specific:
    I’d appreciate it if you wouldn’t ‘gloss over’ the short stories that are giving me traction in the industry.

    Again, uh, what?

  23. Yeah, I have to agree with F & Stephanie. Mr. Tomlinson got defensive about his short stories being dissed, when his short stories hadn’t yet been part of the conversation. Uh, what?

    “I think the writers of the ‘golden age’ of science fiction – Asimov and Heinlein especially – all did their best work in their early short stories. Even L. Ron Hubbard wrote some good short SF before he went off the deep end.”

    How is that “glossing over” the medium of the short story? It reads to me like a hearty endorsement, which got Tomlinson’s panties in a wad.

    This is where I first see the thread go sour, and it’s Tomlinson’s post. “I’m sorry, F, I tried to use small to medium sized words in common usage throughout the English speaking world, but clearly I’ve failed. What particular part of my post is giving you trouble, big boy?”

    Between the random outburst and the painfully dogged defense of his rudeness, Mr. Tomlinson has convinced me to not read his work.

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