Asteroid comparison chart, Part II

By Phil Plait | December 9, 2010 6:50 am

I’ve been meaning to let y’all know about this: a while back I wrote how Emily Lakdawalla of the Planetary Society blog put together a scaled asteroid/comet size comparison chart. Well, she’s updated it to include the nucleus of Hartley 2, visited by the EPOXI spacecraft last month.


The arrow points to the new addition of Hartley 2. It’s tiny! Well, compared to Lutetia, an asteroid well over 100 km across. Mind you, this chart shows every asteroid and comet we’ve ever visited and photographed with spacecraft! That’s 14 in total; I don’t know whether to be amazed that it’s that many, or sad that it isn’t more. Maybe a little of both. But Dawn will visit the asteroids Ceres and Vesta starting next year. More comets are coming up too, which means more incredible pictures and important science is coming up in the near future, too. And that’s definitely good news.

Here are some other images of the comet Hartley 2. Use the thumbnails and arrows to browse, and click on the images to go through to blog posts with more details and descriptions.



CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (23)

  1. In the larger version of the picture, you can see a dark speck on the upper right region of Lutetia. Clearly, this some sort of life form posing for the shot. Proof of alien life! Call Hoagland!

    Seriously cool chart, though. And poor Itokawa. So tiny.

  2. Messier Tidy Upper

    Excellent news! I was wondering – and really hoping she’d do this update. I
    love this poster – & how we have it available. :-)

    Wow .. Hartley 2 is so small. As is Itokawa. One small space rock & one tiny space dirty snowball – how symmettrically apt. Now we just need to image a cometary nucleus the rough equivalent size of Lutetia for balance .. ūüėČ

    Can’t wait to see the version that includes Vesta & Ceres.

    @ Todd W. : “Call Hoagland!”

    On second thoughts folks – please don’t! ūüėČ

  3. Gary Ansorge

    Dang, that’s a lot of out gassing for such a small rock. I couldn’t find data on its rotational rate but I assume it can’t be too high, else it would fly apart.

    So, we’re figuring it will run out of CO2 in a few hundred years? How lucky we are to be able to see it in all it’s fizzing glory.

    Hmmm,,,CO2. That, some H2O, sunlight and a few minerals(and of course a containment envelop for atmosphere) and we could turn it into a food factory,,,for space settlers. Nitrates and phosphates are the first compounds I can think of we’d need to import for that process. Unless there’s phosphorus and nitrogen in its composition,,,mumble,mumble,,,wonder where can I file my space minerals claim?

    Gary 7
    PS. I think it was the comedian Steven Wright who said “Sometimes my mind wanders. Once it wandered clear to Venus,,,” or Hartley 2,,,(in reference to the dark spot mentioned by, 1. Todd W.)

  4. Yeah! Go Dawn! Ceres and Vesta. Now they would be cool to visit. In person. Ah well, looks like I’m going to have to wait a while…

  5. @Gary Ansorge

    Hmmm,,,CO2. That, some H2O, sunlight and a few minerals(and of course a containment envelop for atmosphere) and we could turn it into a food factory,,,for space settlers.

    Heh…space lunch wagon?

  6. Sam H

    The best part about the chart, IMHO is that little Itokawa is roughly the same size (or bigger, depending on which letter you use :)) as the good starship whose travels inspired so many (including me) to look toward the stars, and hope and wonder and dream. I just love imagining the technological might of the Enterprise still being helplessly dwarfed as Sulu gently guides her ’round Lutetia, Kirk and crew feeling microscopic compared to it’s colossal, cratered, Delaware-sized rocky might (It could even make a poem). No matter how far technology progresses, the universe will never cease to amaze us and fill us with childlike wonder, humility and awe (that is, of course if you take the time to look up ;))!

  7. KC

    Very cool. I can’t wait for Dawn!

    Sad news re: the Japanese Venus probe. I feel sorry for the engineers and scientists who worked so hard on that mission. All’s not lost but having to wait 6 more years? Sheesh!

  8. CameronSS

    @Todd W.: Thanks for pointing that out, I was trying to get the speck of crud off my screen.

  9. QuietDesperation

    Can I get one with a nice view? What’s the neighborhood like? What sort of financing is available?

  10. Bob Allee

    Looks like Halley in reverse.

  11. Aww, Itokawa’s even cuter :3

    Hi tiny little asteroid! Who’s a little asteroid? You are! That’s right!

  12. Tim G

    I’m looking forward to getting a good look at the second largest asteroid, Vesta when the Dawn probe will be close in July.

  13. Jamie Mueller

    Why when I read “Call Hoagland!” I hear Colenel Klink’s voice: “HOGAN!”
    Is it just me?

  14. Bill Roberts

    Hartely, Halley and Braille all seem to share the “turkey drumstick” shape, at least from those angles. Is there any thought as to a common cause (e.g., that they started out as two separate comets that collided and weakly stuck to each other)?

  15. @Bill Roberts

    Hartely, Halley and Braille

    Sounds like a law firm. Probably the firm used by the guy standing on Lutetia when he sues for unauthorized use of his image.

  16. Matt B.

    What, no “Click to millenniumfalconate”?

    I’m saving this picture for my collection.

  17. Some of the jets appear to originate on the dark side of the comet. What is illuminating them? Is the comet slightly transparent, with sunlight leaking through? Or is it an optical illusion that when a dark side jet emerges from the shadow of the comet, the point of emergence looks like a crater in the comet.

  18. Sean

    Any thoughts on which of these asteroids might be a candidate for future mining or habitation?

    The little baby ones look like they’d have lots of useful volatile chemicals and no gravity (worth mentioning) to contend with.


  19. Messier Tidy Upper

    @ ^ Sean : 18.

    Any thoughts on which of these asteroids might be a candidate for future mining or habitation?

    Well I think we’ll probably start with the nearer ones in Earth crossing orbits. Perhaps Earth’s quasi-moons such as Cruithne :

    which features in Stephen Baxter’s Manifold trilogy will be the very first one investigated?

    Another possible candidate is :

    Arthur C. Clarke has argued that Icarus, which has an eccentric orbit that takes it from beyond Mars to inside Mercury, would make a useful observation post. He suggested a science station could be set up there to explore the inner solar system using the asteroid’s bulk to let us see the Sun up close.

    Another possibility with a similiar orbit to Icarus that would be an interesting target is 3200 Phaethon which has comet-like characteristics and could well be an ex-comet masquerading as an asteroid.

    Further out, I expect that once we’ve explored some nearer examples we’ll head for the more distant asteroid belt examples such as Ceres, Vesta, Pallas, Juno, Hygiea etc .. There’s plenty to choose from of possible significance there & I think we’ll explore many hopping form rock to rock.

    As well as those largest one’s there’s Kalliope (22) is potentially interesting for possibly being the source of the meteorite that is the Muslim Kaaba rock – as Carl Sagan suggested.

    Plus there’s one inner main belt example of special significance to folks who love this blog and science a certain asteroid 165347 Philplait :

    that I hope people might visit one day. :-)

    So. Many. Possibilities.

    If we can only garner the will and develop the technology to go.

    The more distant the asteroid and the more highly inclined the orbit the longer its likely to take Humanity to get there so bear that in mind but ihope we’ll see a lot of them explored one day. I’d rather that day came sooner than later too.

  20. Messier Tidy Upper

    See also :

    as a starting point from which you can guess for yourself.

    For instance there’s the notorious Earth-menacing (well now not-so much but still) Apophis :

    & as mentioned above Phaethon

    among many other likely candidates.

    Out of left field – and depending on how you define it – there’s even the Martian moons Phobos & Deimos as they could be former asteroids.

    Also, again depending on how you look at things we might *already* be mining asteroids – just look up up how the Sudbury area probably got its mineral resources fr’ex! ūüėČ

  21. réalta fuar

    @ Matt B: “millenniumfalconate”, that’s rich and I’m sure we’ll see that monstrosity soon, if we haven’t already! Great image by Ms. Lakdawalla though and my thanks to her for going through the effort to create it.

  22. Grimbold

    Haha. When Ceres and Vesta get put on this chart, everything that’s on it now will be just little scraps in one corner.

    Does anyone know the status of the Deep Impact probe? Is it going to be doing more science?

  23. Troy

    There should be at least one more. Most outgoing probes since Galileo have been directed to fly by an asteroid. Cassini was originally going to fly by one out bound to Saturn but it was cancelled to appease the government bean counters. Still you’re right, Phil, it is some nice progress and I’m so happy DAWN survived the budget ax and is going to meet up with Vesta next year, and later in 2015 when it hits Ceres I bet it will be brought up as a rival to Mars for a human colonization.


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