Vesta in breathtaking detail

By Phil Plait | August 1, 2011 10:49 am

NASA’s Dawn mission team just revealed the first full-frame image of the giant main-belt asteroid Vesta, and it’s really, really cool:

Yegads! [Click to asteroidenate.]

Vesta is about 500 km (300 miles) across, but is clearly non-spherical, so take that as an average. That’s roughly the size of Colorado! So it’s a big rock, and we’re now seeing it in exquisite detail. This image was taken on July 24, from a distance of about 5000 km (3000 miles).

Man, there’s nothing like being there.

There’s a lot to see. The surface of Vesta is varied, with craters of various sizes (as expected) and depths. I’m very curious to see that there are some darker spots (like in this image) that look like material dredged up from under the surface from impacts; we see this on the Moon and other bodies as well. Some preliminary mineralogical maps show varied distributions of minerals on the surface as well.

An animation of Vesta rotating has also been put together, and really shows how odd this little world is:

[Make sure to set the resolution to at least 720p!]

Look at how the surface changes: you can see smoother regions, cratered regions, places that are darker, some where it’s brighter. Clearly Vesta has been battered over time — the entire south pole region is an impact basin, and those parallel grooves are from waves of energy moving through the asteroid during the impact event — and hopefully its history will be unraveled when higher-resolution images come in.

In fact, the scientists at the press conference talked at length about how these first images have raised a lot of questions, and stressed several times how more images will reveal the answers. Dawn will orbit Vesta for a full (Earth) year, so we should get plenty of data that will keep folks busy for a long time.

… and it won’t end there. After Dawn leaves Vesta it’ll head over the Ceres, the largest of the main belt asteroids. I wonder what it’ll find there? But it’s too soon to worry about that! We have a whole new world to explore for now.

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA


Related posts:

- Dawn of a new Vesta
- Dawn approaches
- On approach to Vesta
- Hubble spins an asteroid

CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post
MORE ABOUT: asteroid, Dawn, impact, Vesta

Comments (47)

  1. ceramicfundamentalist
  2. Aaron

    So cool!

    Hooray for SCIENCE!!!

  3. Steve

    Can I get a Holy Haleakala brothers and sisters?

  4. John

    Freaking awesome

  5. Eric

    Thank God for some good news after an otherwise crappy weekend.

    So what’s the dark stuff? Organic / carbon rich materials?

  6. fmobus

    is it just me or that black crater looks a lot like the bussiness end of a planet-killing weapon?

  7. uudale

    That dark crater almost looks like an artificial construct…

    (cue Hoagland)

  8. Vern Balbert

    What’s the gravitational force at the surface of Vesta?

  9. Very cool!
    Since Vern already asked what I was going to ask, I’ll point this out instead: YouTube’s ad placement algorithms can’t distinguish between science and pseudoscience. One of the ads that came up after the video is for a site that promises to teach you “Quantum Jumping,” which it describes as “a visualization process where you use your mind to ‘jump’ into parallel dimensions, and gain creativity, knowledge, wisdom, skills and inspiration from alternate versions of yourself.” Wow.

  10. Navneeth

    Ceres, the largest of the main belt asteroids.

    *Cough*smallest-dwarf-planet*cough*

  11. MT-LA

    Maybe this has already been covered somewhere else, but how can an asteroid have a south pole (or north pole for that matter)? Are poles defined by the magnetic poles, or is it simply by the axis of spin?

  12. Zombie

    So, is it nonspherical enough that we can doubt that Vesta is in hydrostatic equilibrium?

    Also, that quantum jumping s*!# makes me rage. :P

  13. Gilberto

    @uudale Maybe the dark crater is an old Volcano. Some of the things that mesmerized me are the striped channels at the equator, were they created when the big impact happened at the South Pole?

    Thank God, for the bless of Discovering and letting us witness!!!

    WOW

  14. Donnie B.

    Fantastic!

    I can’t see these images without thinking about Asimov’s very first published short story. Indeed, being marooned off Vesta would put you in a lonely place.

  15. SplendidMonkey

    Related to Vern’s question, how high could a person jump, orbit?

  16. #6 fmobus and #7 uudale: My first thought was, “Somebody stuck a sundial on Vesta??” Now, where’s the equivalent of the “Face on Mars”?

  17. SplendidMonkey

    If it were solid granite, it’s mass ratio to earth would be ~3 × 10-14. I’m thinking a guy could jump and just keep on going. But trying to get to jumping stance might be hard, you’d try to crouch and find yourself floating.

  18. Jamey

    @SplendidMonkey – You know that whole jumping into orbit thing people keep talking about with asteroids?

    Well, the jump is essentially an instantaneous impulse. And so, unless you carry something to use to generate a new impulse, your trajectory is going to try to return you to the point of your last impulse, at the same velocity (ignoring minor irregularities in the shape of the gravitational field, due to the body not being perfectly spherical). Now, velocity is a vector – so it’s going to try to put you at the same spot on the ground, more or less, moving up and away from the ground – which means that at some point, you *HIT* the ground trying to go through it so you can come back up to that initial launch point.

    Now, in theory, you could somehow jump from the highest peak on the body, perfectly tangentially to the ground, and the rotation of the body would most likely move the peak out from under you at first – and when it does come back around, if the peak isn’t too big, you could kind of wiggle yourself around doing a kind of cartwheel.

    Good luck on getting the timing on that *just perfect*.

    Now, seriously, you’re doing this on a *VERY* small chunk of rock, with no real atmosphere to breath should you take too long to get back down, or should you not stick the landing, or not wiggle around that peak just right…

    Let’s not, and just make computer animations of ourselves doing it that we can show everyone and claim we did it.

  19. Pete Jackson

    Now I know where I’ve seen Vesta before. I once left a raisin bun in the basement and came across it about a year later…

  20. ISeeAliens

    Wow, look there is a landing strip right below the dark crater! Proof that aliens do exist! ‘Cuz you know, alien spacecraft needs landing strips because of all the space air out there.

    “Why it’s better that water, it’s man-made water.” -The X from outerspace aka Daikaijū Girara (1967).

  21. CraterJoe

    Cool!

    The three craters that appear to be chained together on the left side of the picture; Are they from simultaneous impacts? If so did they strike at the same time?

  22. Bob

    That’s clearly a thermal exhaust port; should come in handy later…

  23. I fail to see what is so interesting about a giant rock in space. How will this help me build my Galactic Empire? Can it be used as a weapon? Perhaps a staging area for invasion of the outer solar system? You scientist-geeks are an amusing lot, always celebrating things that are of no consequence. Without the Dark Side of the Force to motivate our space exploration efforts, this civilization will continue to go nowhere.

  24. CameronSS

    1. Construct massive space-phonograph.
    2. Send to Vesta
    3. Place space-needle in groove, record to CD
    4. ?????
    5. Profit!

  25. Messier Tidy Upper

    Superluminous image! Great work, thanks Dawn and the BA for keeping us updated on it’s progress too. :-)

    @3. Steve Says: “Can I get a Holy Haleakala brothers and sisters?”

    You can indeed : HOLY HALEAKALA! 8)

    Guess we can now say that Vesta is no longer virgin territory as a new Dawn in our understanding of the brightest asteroid arrives! ;-)

  26. Egad

    Looks like it has at least two double craters created by simultaneous-ish impact of binary asteroids. The bigger pair is really big.

    And grooooves!!!

  27. Nic

    I was born in 1966. Thus at my first school (71+) any astronomy pictures, particularly of objects in the Solar System (except the Moon maybe) were a bit rubbish. Before the Voyagers, before Pioneers 10&11; at the time I loved the pictures of distant nebulae, they were just prettier, more colorful. (Give me a break! I still like ‘em and I was young)..
    Since of course we have such wonderful pictures as the above – I recall a textbook in the 70′s (possibly old even then) with a pic of Saturn that any modern amateur would sneer at.
    I am 45 soon – a few weeks – the stuff we now get is beyond anything I would have imagined possible, until perhaps I saw the first Voyager pics. And here we are again, our robotic friends are rather good at their jobs aren’t they?
    Cheers Phil, nice post.

  28. @Jamey Note that I am not a physics/astronomer (nor is English my native language :D ) and although I do understand the “jumping from the highest peak and rotation moving the peak out from under you” part of your example, the way I see it – regarding jumping off of the asteroid – is more similar to what @SplendidMonkey said above in his comment.

    I mean in my layman’s opinion if the “chunk of rock” is VERY small (small as Vesta or even smaller, see below paragraph) there might not be enough gravitational force/pull to pull you back (to the “point of your last impulse”) and return you to the ground.

    For example, what about if the asteroid in question would be only 10 miles in diameter (or only 1 mile etc.), would this rule that you’ve described still apply?

    But then again, I still have so much to learn… :)

  29. Grand Lunar

    Would it be correct to say that Vesta is a “groovy” place to be?

    Some of those craters really stand out.

    I wonder what else we’ll find here?

  30. Jamey

    @Tadej: Certainly, if the body is small enough, you can reach escape velocity for that body (though you’re not, by human power, going to escape the solar system as a whole anywhere within the Oort cloud or so…)

    Escape velocity for Vesta, according to Wikipedia, is .35 km/sec – 350 meters/sec, or about 790 miles per hour. So, not jumping off of *that* one, though if there were an atmosphere, almost any jet capable of reaching supersonic speeds would work. And yet, there’d have to be more gravity to have that much atmosphere, so…

    23 miles per hour nets you escape velocity from Eros. Still not quite running speed. Visiting Itokawa, about a quarter mile long, finds you with an escape velocity of half of a mile per hour, so even a normal walk ends with you in trouble. Phobos and Deimos are in the same size range as Eros, so you’re looking at about the same speeds there.

    So yeah, in theory, on a really small rock, you’re going to get to jump to a very cold and lonely death, unless Tom Corbett happens to be handy.

    I’m still thinking computer animations and wild claims at the bar later are a better solution.

  31. Anchor

    “…and those parallel grooves are from waves of energy moving through the asteroid during the impact event…”

    Hmmm…you sure about that?

  32. SkyGazer

    500km… that´s Amsterdam-Paris.
    Put three on a row and you cover Amsterdam-Mallorca…

  33. You all have it soooooo wrong. Those are tire tracks!

    This must be where they build and test monster trucks.

  34. Nigel Depledge

    Tadej (29) said:

    I mean in my layman’s opinion if the “chunk of rock” is VERY small (small as Vesta or even smaller, see below paragraph) there might not be enough gravitational force/pull to pull you back (to the “point of your last impulse”) and return you to the ground.

    For example, what about if the asteroid in question would be only 10 miles in diameter (or only 1 mile etc.), would this rule that you’ve described still apply?

    Well, I am not a physicist / astronomer either, but if I understand correctly it doesn’t matter how far away from the rock you get, you will still experience its gravitational influence. The only way in which you can ever not fall back to the rock is if some other massive body captures you.

    So, if you go into orbit around the rock, the point of your last mpulse will be on that orbit, and since you pushed off from the rock to get that impulse, your orbit must intersect with the surface of the rock.

  35. Nigel Depledge

    Oh, I just read #31, and it looks like I got it a bit wrong in #35.

  36. Peter B

    MT-LA @ #11 asked: “…how can an asteroid have a south pole (or north pole for that matter)?”

    Because it’s spinning. At two points on Vesta’s surface, the axis of rotation intersects the surface, just like on Earth. As to which one is the North Pole and which one is the South Pole, I assume it’s determined by whether it’s spinning the same direction as the Earth or the opposite direction.

    “Are poles defined by the magnetic poles, or is it simply by the axis of spin?”

    I’m going to guess the second. I doubt Vesta has a magnetic field, though I suppose that just means it’s waiting there to surprise astronomers…

  37. andy

    Usual convention is that the north pole is defined as the rotational pole that lies above the invariable plane of the solar system (the plane normal to the sum of the orbital angular momentum vectors of the major planets). This causes interesting problems if you have an object whose axis precesses above and below this plane.

    The other and in my opinion more logical choice is to use the sense of the rotation to define north by sense of rotation (look down on the north pole and the planet appears to rotate anticlockwise), but this can be more difficult to determine observationally.

  38. Herbert

    Is it just my impression or its “squased”? It seems that there are depression “lines” on its equator and that its squeezed on its poles (based on the video).

  39. CB

    @ MT-LA
    “Pole” referred first to the place where the axis of rotation meets the surface, and only later was this concept applied to magnetism. The convention that a magnet has a “North” and “South” pole was due to associating the earth’s magnetic field with its axis of rotation, not the other way around.

    When our planet’s magnetic field flips again, North on the globe will still be North, even though the earth’s magnetic “North” pole will be in the Southern hemisphere. :)

    @ Jamey:

    It’s not actually true that your trajectory necessarily will bring you back to the same point. The amount of gravitational potential energy for an object that is at infinite distance from the source of gravity is not infinite — the integral of 1/r^2, from r0 > 0 to infinity, converges.

    Ergo there is some amount of kinetic energy that you can apply to an object where it will never slow to a stop or turn around due the gravity of the body it originally was launched from. This is what “escape velocity” means.

  40. andy

    Of course near an irregularly-shaped object such as Vesta the trajectories become far more interesting…

  41. CR

    So, at very first glance on the un-enlarged version of the pic, did the dark crater remind anyone else of Moonbase Alpha?
    And I already know that said dark crater has already spawned a host of ‘alien artifact’ jokes… after my “Huh, it’s Moonbase Alpha” notion, I immediately thought about the latest ‘face on Mars’ proponents crawling out of the woodwork. Sadly, there shall be some who honestly claim that it REALLY IS evidence of aliens! (I have an OLD ViewMaster reel set of Tom Corbett that tells the fanciful tale of finding a lost civilization amid the asteroids, after finding other evidence of it on Mars. Really creative and nice model work for the 3D picture reels–especially for the time in which they were manufactured–but not a true story, in spite of what others may claim!)

    The topography reminds me a little of the Martian moons, which is neat… in spite of the difference in size/mass, might they all be of similar compostion to have had their terrain affected in similar ways?

    Anyway, even though it’s just a ‘chunk of rock’ in space, I find this asteroid amazing… heck, all the asteroids have been amazing, once seen up close! I can’t wait to see more details of Vesta, and am really looking forward to Ceres!

  42. Thanks all for the replies. Yes now I think I understand it, finally… :) Though one thing is also interesting (regarding escape velocities), in particular I am talking about this sentence below from an article on Wikipedia about escape velocity:

    “A rocket moving out of a gravity well does not actually need to attain escape velocity to do so, but could achieve the same result at walking speed with a suitable mode of propulsion and sufficient fuel. Escape velocity only applies to ballistic trajectories.”

    Apparently escape velocity applies only to ballistics? Also, as I’ve read in another article (actually the same article but on Slovenian Wikipedia :D ), spacecrafts don’t need to reach the actual speed as it’s specified as planet Earth’s escape velocity (in that same Wikipedia article); they first travel to lower orbit (with lower speed, obviously) and then accelerate further to escape velocity at this specific height (which is slightly less; the article says it’s about 10.9 km/s) so in the end that extra required speed is lower as the vessel is already accelerated to a speed of about 8 km/s.

    I really hope I’ve translated it correctly (I did it as best as can). :)

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