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Space Science

Holmes Comet Coma Grows Bigger Than The Sun 245

coondoggie passed us a NetworkWorld article, as he does, noting that there is now an object in our solar system bigger than Sol. The Holmes comet has a huge coma, with a diameter scientists are now calculating to be larger than our own middle-sized star. "Scientists don't seem to have a guess as to how big it will ultimately become. The Holmes coma's diameter on Nov. 9 was 869,900 miles (1.4 million kilometers), based on measurements by Rachel Stevenson, Jan Kleyna and Pedro Lacerda of the University of Hawaii Institute for Astronomy. The sun's diameter, stated differently by various sources, is about 864,900 miles (1.392 million kilometers)."
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Holmes Comet Coma Grows Bigger Than The Sun

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  • Name (Score:4, Insightful)

    by Anonymous Coward on Thursday November 15, 2007 @03:06PM (#21368307)
    Look, don't try to sound cool by calling the sun "Sol". It just sounds pompous.
    • Correct != pompous (Score:5, Insightful)

      by Anonymous Coward on Thursday November 15, 2007 @03:40PM (#21368821)
      Our sun's name is "Sol." It is correct to call it by its proper name.

      I don't think it makes the speaker sound pompous at all. Appealing to one's own ethos to strengthen an argument makes someone sound pompous. Quoting the law to justify an opinion about morality makes someone sound pompous. Using the word "Virii" to mean "more than one computer virus" makes a speaker sound pompous, and is also incorrect.

      But simply speaking in a technically precise manner, especially to a science-literate target audience on a techie/geeky website, is not in the least bit pompous.

      I would go so far as to call it "expected."

    • Indeed, it reminds of a Mexican beer that tastes like soapy piss.
      • Indeed, it reminds of a Mexican beer that tastes like soapy piss.

        I do not want to know how you would even know this.

        Regarding the use of Sol for the Sun, yeah, it comes off a little pretentious, but it is the name given to it, even if it translates back to 'sun'. Latin names make everything sound cooler, anywho. Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam.

    • by fm6 ( 162816 )
      Or maybe less parochial? If there are any inhabitants of planets circling nearby suns, I imagine they'd object to our referring to our sun as the sun.

      Which is why SF often refers to "the sun" as "Sol", "the moon" as "Luna", etc. Probably where the poster picked up the habit.
      • by tjstork ( 137384 )
        Or maybe less parochial? If there are any inhabitants of planets circling nearby suns, I imagine they'd object to our referring to our sun as the sun.

        It's silly that they do that. We call our Sun, the Sun, and our moon, the Moon. It's simple and its accurate. If the inhabitants of other planets on other stars call their suns something, they could call it whatever they want, and I highly doubt they speak English... We might have to call Rigel "blahtak", or something.

        • Re: (Score:3, Informative)

          by spun ( 1352 )
          And we'll just call you 'person' rather than calling you by your name. A sun is a type of thing, Sol is the name of the sun that happens to be closes to us. In any language used by creatures living on planets, there will be a word for 'sun.' But 'Sol' will still be unique. When we have colonies on Mars, what will the people living there be referring to when they say, "The moon has just risen?"

          And 'we' do not call our sun, 'the sun,' except in English. Stop being so parochial, I mean, don't you think we shou
          • by PCM2 ( 4486 )

            A sun is a type of thing, Sol is the name of the sun that happens to be closes to us.

            Got any data to back that up? I know they call it Sol a lot in sci-fi paperbacks and on Star Trek, but do any scientists actually use that designation?

            • by spun ( 1352 )
              Hmm, you know, I just took it for granted that scientists call it that because science journalists tend to call it that at least as often as they call it the sun. And 'Sol' means 'Sun' in Latin, and scientists love to use Latin. It also means sun in most Latin derived languages, so even if there are no English speaking scientists who call it sol, there are many scientists who have no other word for it.
          • Re: (Score:2, Interesting)

            by foobsr ( 693224 ) *
            In any language used by creatures living on planets, there will be a word for 'sun.'

            It seems there (probably) exist 'ejected' planets which could sustain life.

            http://www.world-science.net/exclusives/070910_sunless-planets.htm [world-science.net]

            Apart from that, it is likely to be difficult to make predictions with regard to language (Living without Numbers or Time [spiegel.de]).

            CC.
          • Re:Name (Score:5, Insightful)

            by h4rm0ny ( 722443 ) on Thursday November 15, 2007 @06:29PM (#21371279) Journal

            A sun is a type of thing, Sol is the name of the sun that happens to be closes to us.


            Oh no! No. This is as bad as all those people who have started pronouncing Uranus "your-an-us" rather than "your-a-nus" because they think it sounds more scientific that way. As if sounding "scientific" is a good thing as opposed to trying to make things as understandable as possible (and funny). A sun is not a type of thing. You can say it to mean that, put it with a lower case 's' and people will know what you mean, but we have a word that specifically means that with no ambiguity and the word is star. We have been calling the Sun "the Sun" for a long, long time. Other languages have their own words for the Sun and they are direct equivalents. They don't mean "stars" or even "stars with planets around them." Each word means, quite specifically The Sun. And the interesting thing is that one of those languages is Latin and its word for the Sun is "Sol." It is the direct equivalent word with the same meaning. Why you think translating something into another language is suddenly correct and using the native word incorrect I don't know. But I am suspicious that it is that same creeping desire on the part of some people to sound "scientific." The English speaking world has used the Sun for centuries quite happily without any ambiguity which has appeared out of nowhere in recent years.

            The overwhelming majority of English speakers call it the Sun and don't mean stars and wouldn't think to mean stars. Almost nobody calls it Sol. Why introduce confusion?

            The Sun. The Stars. Uranus [rude pronunciation].

            Thank you.
            • Re: (Score:3, Informative)

              by LordSnooty ( 853791 )
              Exactly, people use the non-rude pronunciation precisely to avoid sniggering and off-topic giggles about butts. It's not about sounding scientific as such.
          • Re: (Score:3, Funny)

            by magarity ( 164372 )
            Where were you to back me up when the geology teacher in grade 11 asked on a quiz 'what is the name of the star this planet orbits?' He marked me wrong for putting 'Sol' instead of 'the Sun' (same for Luna and Terra on the same quiz). I pointed out the name of the thing was indeed 'Sol' and that putting 'the' in front of it meant the word sun wasn't a proper name. He admitted that even though I was technically correct it wasn't the answer he was looking for so 10% off for each of the 3 anyway. Now THAT
          • Re: (Score:3, Interesting)

            by tjstork ( 137384 )
            And 'we' do not call our sun, 'the sun,' except in English.

            By the way, the naming convention of "first in class" is also used in shipbuilding. There is a USS Nimitz, and, then, there is a Nimitz class carrier. The British came up with the first in class naval tradition and we copied it. For example, during World War II, they had the King George V, and the King George V class battleship.

            So, to call the Sun a sun and the Moon the moon is entirely accurate and consistent with the human tradition. Certainl
      • Re:Name (Score:5, Funny)

        by drfireman ( 101623 ) <dan@[ ]berg.com ['kim' in gap]> on Thursday November 15, 2007 @04:51PM (#21369935) Homepage
        I inhabit a planet circling a nearby "sun." Actually, we call our "sun" Sol, and we find it a little insulting that your SF writers have assumed the name was unclaimed. Stop it. We don't call our "moon" Luna, so you're safe there, but I have to say, on behalf of my people, that it sounds stupid, and "moon" wasn't taken anyway (we call our little satellite thing "Kodak"). There's lots of other stuff you guys have wrong, too, but here on our planet we're not really supposed to be reading Slashdot during work hours. Maybe I'll post from home later.
      • Re: (Score:3, Insightful)

        by Belial6 ( 794905 )
        Unless Gene Roddenberry is correct, and somehow every creature in the galaxy speaks English, I would say that not only would they not be offended by the word Sun being use to describe the star that we circle, but they might just be willing to call our glichblick'click'click by the same name we use, which is Sun. The big fiery ball in the sky is called Sun by [pulling number out of ass] 99.9% of all English speaking humans. That means that in English, the big fiery ball in the sky's name is... That's right
  • by explosivejared ( 1186049 ) <`moc.liamg' `ta' `deraj.nagah'> on Thursday November 15, 2007 @03:06PM (#21368313)
    Sol now jealous of the precocious, scampy little comet's meteoric rise in popularity and size has become addicted to painkillers and alcohol. Friends close to the star hope to be able to talk the down-and-out celestial body into going to rehab.
  • I welcome our giant comet overlords. When we are put to work to toil in their ice and ammonia mines, or whatever this comet is made of, we can say to ourselves, 'This sure beats working on the surface of the Sun, we sure put one over on old Sol!"
  • by gardyloo ( 512791 ) on Thursday November 15, 2007 @03:12PM (#21368393)
    Yes, this is pedantic, but by practically any definition (even leaving aside unbounded electromagnetic radiation or mass), Sol is FAR larger than the comet. The very fact that the comet HAS a tail of sorts speaks to the influence of the solar wind.

          I'd guess that the diameter that most people talk about when they're discussing the sun is that determined by the mean-free scatting path length of photons produced within the sun. Once the photons' probability for escaping the sun is higher than that for being scattered back into the interior, that's what we usually call the "diameter", and it accounts for the relatively sharp "edge" to the sun.

          I could release a bunch of helium atoms on Earth's surface, and eventually they'd diffuse enough to be effectively larger than the sun's "diameter" as defined in the articles. It still doesn't mean a whole lot.
    • Re: (Score:3, Funny)

      by gardyloo ( 512791 )

      mean-free scatting path length
      Gaaagh! I want my local star neither improvising vocal jazz nor, um, whatever else that word might refer to. Sorry.
    • Re: (Score:2, Informative)

      by dotancohen ( 1015143 )
      Measuring by mass, the sun is the largest object in the solar system. But the term "large", when used without specifying which measurement is being referred to, usually refers to length. Thus, for solar objects, diameter. By that measurement, Holmes is technically larger than the sun. The sun remains, however, more massive.
      • by Anonymous Coward on Thursday November 15, 2007 @04:12PM (#21369309)

        But the term "large", when used without specifying which measurement is being referred to, usually refers to length. Thus, for solar objects, diameter. By that measurement, Holmes is technically larger than the sun.

        This depends - as the parent post already pointed out - entirely on how you define the diameter of the object in question. And - again, as the parent post already pointed out - the diameter of the sun is usually defined by that part of the sun which emits most of the photons that reach us from the sun. By most other definitions - and there are lots of them that do make sense - the diameter of the sun is larger. Much larger, in fact.

        Incidentally, if you define the diameter of the sun using a measure that more-or-less matches the one used for defining the diameter of a comet's coma - namely, the diameter of the gas cloud emitted by the object in question - you'll get the entire heliosphere. Which is way larger than the coma of 17P/Holmes.

      • Re: (Score:3, Insightful)

        by osu-neko ( 2604 )
        Not really, no. Using the same standards for measurement, the diameter of the sun is over 800,000 miles, whereas the diameter of the comet is only a few miles. OTOH, if you want to include the coma, then the diameter of Holmes is over 800,000 miles, but the diameter of the sun is over ten billion miles (assuming you measure the short distance across the coma/heliopause and not down the length of their respective tails).
    • I'd guess that the diameter that most people talk about when they're discussing the sun is that determined by the mean-free scatting path length of photons produced within the sun.

      Eeeww!!

      Photon poo everywhere!! :-P

      Cheers

  • Cool, in theory (Score:3, Insightful)

    by Otter ( 3800 ) on Thursday November 15, 2007 @03:18PM (#21368489) Journal
    I guess that's interesting on some level, but for all the fuss about this comet I was expecting something more Hale-Boppish. Not just some barely visible, round blur.
    • You don't find a fairly run-of-the-mill comet suddenly displaying a massive outburst and a million-fold increase in brightness, along with a truly *massive* coma, fascinating?

      TBH, your post belies an attitude which saddens me... the fact that the visual impact of thing is more important than the scientific reality of it. It's part of the reason I avoid showing people nebulae and star clusters in my telescope. While they are scientifically fascinating objects, they simply don't have the real-life impact th
      • Re: (Score:3, Interesting)

        by Otter ( 3800 )
        TBH, your post belies an attitude which saddens me... the fact that the visual impact of thing is more important than the scientific reality of it.

        It's not a matter of "more important", just that astrophysics and stargazing are two different things. The pulsar with planets is cool, even if we can't look up and see it. But Holmes has been hyped for its visual impact, which I'd say is .. lacking.

        • But Holmes has been hyped for its visual impact, which I'd say is .. lacking.

          Well, I think it's more accurate to say that, unlike, say, Hale-Bopp or Hyukatake, the visual impact of Holmes can only be truly appreciated if you understand the science of it. Consider, the coma of this thing is *huge*. Sure, it may look like a fuzzy ball, but it's a fuzzy ball with a truly massive angular extent, generated by an object that's barely resolvable as a point in an average telescope. That's pretty freakin' cool, i
  • by Anonymous Coward
    Clearly named after John Holmes...
  • OBLIGATORY (Score:3, Informative)

    by i_want_you_to_throw_ ( 559379 ) on Thursday November 15, 2007 @03:25PM (#21368605) Journal
    EVERYBODY PANIC!!!!!!
  • by RealGrouchy ( 943109 ) on Thursday November 15, 2007 @03:35PM (#21368753)
    So we'll have to revise the list, then?

    1. Beatles
    2. Jesus
    3. Holmes Comet
    4. Sun

    - RG>
    • If "more popular than" means "bigger than," then sure. Just another misquote that persisted too long.

      http://students.ceid.upatras.gr/~pirli/beatles/jesus.html [upatras.gr]

      On March 4, 1966, in an interview printed in the London Evening Standard, John Lennon made the following statement:

      "Christianity will go. It will vanish and shrink. I needn't argue with that; I'm right and I will be proved right. We're more popular than Jesus now; I don't know which will go first - rock 'n' roll or Christianity. Jesus was all right bu

  • less dense (Score:2, Interesting)

    the larger it gets, the less dense it is, so it may not appear like much when it finally gets eaten by that other star. However, if it has some flammable gases or something cool, we may see a show after all.
  • by mritunjai ( 518932 ) on Thursday November 15, 2007 @03:52PM (#21369029) Homepage
    This just crossed my mind -

    Why not make a satellite hitch ride on one of these comets to the outer reaches of the solar system. Assuming they go there once every round, even hitching Halley's comet will get us further than Pioneer 1&2 have been in a shorter time, without wasting any precious fuel.

    Lesser energy wasted means more energy available to scientific equipments onboard! So they can possibly carry many more equipments and more powerful transmitters.

    Or hell, just hitch a ride on one of these for pretty much anywhere in the solar system. No need to wait 7 yrs to reach Saturn. Hitching a ride on one of these could get us there in months. They move *really* fast!
    • by edremy ( 36408 ) on Thursday November 15, 2007 @04:00PM (#21369145) Journal
      Umm, how? It's a bit tough to snare things moving at kilometers/second relative to your velocity, even assuming that there is something strong enough to grab on to in a comet. If it's not moving at kps relative, then you don't gain anything anyway- you've expended the energy to fly in formation with it.

      You want free energy for spaceflight? There are better ways [wikipedia.org]

    • Unfortunately, scientists have encountered significant difficulties in convincing comets to enter a convenient orbit around the Earth and accelerating back to the oort cloud by their own means.
    • A guy I knew was a cyclist. He had a similar thought but with semi-trucks on a freeway.

      It didn't work out too well.
      • by Bearpaw ( 13080 )
        A guy I knew was a cyclist. He had a similar thought but with semi-trucks on a freeway.


        It didn't work out too well.


        He must not have done it right. I knew someone who made it work really well.

        Once.

    • by inviolet ( 797804 ) <slashdot @ i d e a s m a tter.org> on Thursday November 15, 2007 @04:07PM (#21369233) Journal

      Why not make a satellite hitch ride on one of these comets to the outer reaches of the solar system. Assuming they go there once every round, even hitching Halley's comet will get us further than Pioneer 1&2 have been in a shorter time, without wasting any precious fuel.

      To hitch a ride on a passing comet, you can do one of two things:

      1. Match velocities, and then land on it. -or-

      2. Not match velocities, and then get smashed to bits by it.

      Method 2 easily achieves your goal of travelling to the outer reaches of the solar system "without wasting any precious fuel". However, your satellite will no longer be functional, or even identifiable. But other than that, yeah, it's a great idea. :)

      (Tell me Mrs. Lincoln, other than that, how did you enjoy the theatre?)

    • You still have to match speeds with it, not an easy thing with current technology. Have you done the math on a probe just parked in front of a comet for what the impact energy will be like? Let me give you a hint, it's 1/2mv(squared). Get a big enough probe for the comet to smack into, and you can split it in half. Course, you won't be able to use the probe for much anymore...
  • by Fear the Clam ( 230933 ) on Thursday November 15, 2007 @03:59PM (#21369129)
    The Holmes comet has a huge coma

    And it's headed straight for your black hole, bay-bee.
  • by GrayCalx ( 597428 ) on Thursday November 15, 2007 @04:04PM (#21369183)
    noting that there is now an object in our solar system bigger than Sol.

    I'm pretty sure Jupiter's magnetosphere is still the largest object in the solar system.

    Diameters (approx.)
    Sun : 864,900 miles
    Holmes : 869,900 miles
    Jupiter's Magnetosphere : 16,000,000 miles

    Wiki [wikipedia.org]
    • Re: (Score:3, Insightful)

      by Tarlus ( 1000874 )

      I'm pretty sure Jupiter's magnetosphere is still the largest object in the solar system.
      I wouldn't really call that an object, per se. Of course, I wouldn't really call a coma an object either, though it is at least a cloud-like mass of particles which makes it more of an object than a magnetic field.

      But, I'm no scientist, so I digress. I had no clue that Jupiter had that much magnetic influence. How large is the sun's magnetosphere?
    • by lahvak ( 69490 )
      Maybe that's a bad question, but would would be the size of Sun's magnetosphere?
      • Yeah interesting question. I would say that the sun's magnetosphere would BE the solar system. If that makes sense... but what do I know I've taken zero astronomy classes, I just go by what Discovery tells me, ;)
  • by sacrilicious ( 316896 ) on Thursday November 15, 2007 @04:05PM (#21369197) Homepage
    With a name like Holmes, what did we all expect [wikipedia.org]?
  • by yeremein ( 678037 ) on Thursday November 15, 2007 @04:10PM (#21369281)
    I took a picture of the comet just yesterday. Posted here [flickr.com].

    In fact, I have several photos [flickr.com] of the comet taken over the past few weeks. They're not all cropped the same, but it's still quite apparent how much the comet is expanding. One of these days I plan to put together a composite photo, fixing the stars in place, and showing not only the expansion of the comet but also its motion relative to the stars.
    • by Dunbal ( 464142 )
      omygodit'sheadedstraightforus!
    • by symes ( 835608 )
      Those are some nice photos!
    • Those pictures are very cool.
      I see you used a 600mm telescope. I will try to take some pictures with my 500mm mirror lens. Unfortunatly I don't have a motor mount, so I don't know what I will get.
    • by Kupek ( 75469 )
      Thanks. Those pictures are much more informative than the one in the article.
    • by Cally ( 10873 )
      Is it naked eye? And if so, roughly whereabouts is it? casual stargazers want to know!
      • Re: (Score:3, Informative)

        by yeremein ( 678037 )
        It is certainly visible to the naked eye, and looks distinctly not-star-like. It's spectacular in binoculars.

        Right now it's in Perseus, quite close to the brightest star. It's in the northeast as dusk falls, below Cassiopeia.
  • I was awesome at diameters in grade school, but no one ever told me there was a career path for "diameter scientists." This is easily the most exciting thing about this story, which if anything just tells us that it's a slow news day in the solar system.
  • by Tango42 ( 662363 ) on Thursday November 15, 2007 @06:20PM (#21371173)
    It's nonsense to talk about how big it's going to get. It's expanding in space - it's going to keep expanding forever (the solar wind might stop it expanding symmetrically, though). It will just get thinner and thinner. The interesting thing is that it's still easily visible, but it will start to dim eventually as it gets too thin to reflect much light. The question is how big it will get while still reflecting enough light for it to be visible to the naked eye (in fact, I think only the middle can be seen without a telescope already), and that should be fairly easy to calculate.

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