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The Tenth Planet Shrinks Under Hubble's Gaze 318

starexplorer2001 writes "An object called the 10th planet by some astronomers is not as large as previously thought. New images of 2003 UB313 (aka Xena) were delivered by the Hubble Telescope and showed up as only 1.5 pixels! Now, some are calling to demote Pluto and kill Xena."
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The Tenth Planet Shrinks Under Hubble's Gaze

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  • Blast! (Score:2, Funny)

    by bl4nk ( 607569 )
    This has to be another sinister plot by Aries! Xena should have killed him when she had the chance!
  • atomic? (Score:3, Interesting)

    by caffeinemessiah ( 918089 ) on Wednesday April 12, 2006 @02:39AM (#15111695) Journal
    how exactly do you represent or see half a pixel? i thought pixels were supposed to be atomic...?
    • Re:atomic? (Score:2, Insightful)

      by staticdaze ( 597246 )
      This is off the top of my head, but I would think they could determine that "half pixel" based on the shade of the entire pixel relative to the "main" pixel that actually contains most of the body. If it's 75% darker, assume the object extends 25% into that pixel? Am I close?
      • Re:atomic? (Score:3, Insightful)

        by binarybum ( 468664 )
        maybe, but this still seems bizarre - why not map the pixels into real space and give a value based on a non-discreet scale (like meters or football fields)?
        • Libraries of Congress? It's one of my favorite units.
          • Re:atomic? (Score:2, Funny)

            by StarkRG ( 888216 )
            Hey, as long as we're applying units to measurements of a different type why not measure it in feet/sec, or perhaps in watts? volts? degrees kelvin? how about in hours?

            It's five hours big.
            • Re:atomic? (Score:3, Interesting)

              by visgoth ( 613861 )
              It's five hours big.

              I had chinese buffet for lunch. It was 2 hours big!

              Hey! You might be onto sonmthing here!

    • Re:atomic? (Score:5, Informative)

      by helioquake ( 841463 ) * on Wednesday April 12, 2006 @02:54AM (#15111744) Journal
      A pixel is small, but nowhere near subatomic. It's measured only in microns.

      When photons are distributed over the CCD surfrace, it has some measureable shape (e.g., Gaussian) which can be fitted as such to characterize the shape. The quoted size of 1.5 pixel is, I think, the FWHM of the fitted Gaussian function that characterize its source.
      • I think the GPP meant atomic as in "smallest reduceable unit", which came from the Greek atomos which means "indivisible".

        So, how do you get half a pixel on a screen? I too was under the impression that an individual pixel was either all on or all off...

        • So, how do you get half a pixel on a screen? I too was under the impression that an individual pixel was either all on or all off...

          Do you guys know the concept of "resizing a ditital image"?

          Subsampling of a pixel can be done by knowing the intensity values in the neighboring 8 pixels (or greater). In other words, you can derive the intensity value at the pixel boundary by taking the mean value of the intensity values detected in these two pixels.

          In this case, the measured size is derived based on mathemati
          • Do you guys know the concept of "resizing a ditital image"?

            No. Does it have something to do with enlarging a thumbnail image of breasts?

            Just click on it instead, buddy. Chances are it goes to a full size picture.

        • The pixels in the article aren't binary atoms though and probably have at least two bits of precision: explaining the claim of 1.5 pixels. More generally, most monitors have three different elements for red, green and blue. TrueType, for example, uses these as the atoms rather than the whole pixel, to get smoother screen text. Modern video cards, when using 3D graphics, can sample more than one point for the same pixel. For example, 4X Anti-aliasing can use up to four sample points per pixel.
      • Re:atomic? (Score:5, Informative)

        by Vellmont ( 569020 ) on Wednesday April 12, 2006 @03:09AM (#15111796) Homepage

        A pixel is small, but nowhere near subatomic. It's measured only in microns

        By atomic, the author means it cannot be divided further. This was the original meaning of atom. Atomic is a word used in computer science to indicate an operation that can't be interrupted. It either happens completely, or doesn't happen at all.
        • Which does not fit this case because a pixel can have many colors, by which you can estimate how much of the source is providing light to the pixel.
      • Re:atomic? (Score:2, Insightful)

        by Oink ( 33510 )
        This is true, but I think the question was aimed towards how they supposedly can divide a pixel since it's supposedly the smallest thing they can resolve. I actually worked on a cosmology project for a couple years, so I have at least a rudementary understanding of image capturing techniques. You can overcome the limitations of your CCD through a technique called dithering. The standard dither is 2x2, in which you take an image, move your image to the right by half a pixel, down by half a pixel, left by
    • how exactly do you represent or see half a pixel?

      Think of it as the inverse of anti-aliasing.

    • You can measure "sub-resolution" size by taking repeated measurements and averaging (eg. count the number of pixels ten times and average). This is quite commonly done with a wide variety of sensors to get better resolution than the sensors can provide on a single measurement. Sometime noise is added to the measurements to help improve the resolution.
    • Re:atomic? (Score:3, Insightful)

      by gameforge ( 965493 )
      You guys are making this too complicated. NASA's site [] says: "Located 10 billion miles away, but with a diameter that is a little more than half the width of the United States, Xena is only 1.5 picture elements across in Hubble's Advanced Camera for Surveys' view."

      Think projection in a 3D game. A pixel represents, at a projected distance of 10 billion miles, a width x. Xena is 1.5x.

      The final image (as you all have pointed out) would require a minimum of two pixels of information to accurately reproduce th
    • how exactly do you represent or see half a pixel? i thought pixels were supposed to be atomic...?

  • Maybe... (Score:5, Funny)

    by Anonymous Coward on Wednesday April 12, 2006 @02:40AM (#15111698)
    Maybe it's all black except for a bright white spot.
  • Xena (Score:3, Interesting)

    by Detritus ( 11846 ) on Wednesday April 12, 2006 @02:44AM (#15111713) Homepage
    Forget Xena, the planet should be named Marvin.
  • by core plexus ( 599119 ) on Wednesday April 12, 2006 @02:53AM (#15111739) Homepage
    "I swear it's a foot long, it just shrank because of the cold of space!" --

    New Face discovered on Mars []

  • by svunt ( 916464 ) on Wednesday April 12, 2006 @02:56AM (#15111748) Homepage Journal
    Ah, I still remember fondly the first time I saw a slashdot thread climb to a few hundred posts of argument about 'what makes a planet a planet?'. If ever a term was crying out for a rigid, ostensive definition from astronomers, it's 'planet'. From the ancient greek word for "wanderer", if we don't tighten it up some, the argument will come trotting out every time someone finds a rock doing laps about the sun. Stays within 10 degrees of the ecliptic, say 3,000km across...that works for me.
    • If ever a term was crying out for a rigid, ostensive definition from astronomers, it's 'planet'

      You must be a lawyer. Or perhaps you were just brainwashed by the patent department.

      I suggest that, rather than founding an interplanetary comission (so the Xenians may or may not be in it) for the ultimate definition of planethood, we learn to live with a universe that has a number various sized lumps of matter in it, and use language to explain more precisely what we mean in a particular case should the need ari
    • by Anonymous Coward
      I'm an astronomer (in a different sub-field), and I'm pretty happy with the situation as it stands. The whole is-it-a-planet-or-not debate gets people interested in astronomy, but it's of essentially no significance to us. It's only a name, we care about the reality of things and not the invented names given to them.
      This is a cynical way to put it, and maybe some other astronomers care more than I do. I'd certainly like it if people were more interested in cutting edge research (or detailed politics, comput
    • Personally I always thought the best definition of a planet would be a body with enough mass to pull itself into roughly a sphere. That would discount pluto for now at least. The actual mass doesn't need to be accurately defined - if it's round it's a planet. I don't think we even need to specify that it must orbit a star. If it doesn't have enough mass to pull itself round then it's just a big lump of rock.

  • what scale? (Score:4, Interesting)

    by alphakappa ( 687189 ) on Wednesday April 12, 2006 @03:06AM (#15111779) Homepage
    "New images of 2003 UB313 (aka Xena) were delivered by the Hubble Telescope and showed up as only 1.5 pixels! "

    1.5 pixels on what scale? A pixel is not a unit of measurement for size, it just denotes the smallest distinct unit in a picture. Yes, it appears sensational to say that a 'planet' appeared to be 1.5 pixels (100 exclamation marks), but that's just as stupid as saying that my backyard appears to be 5 pixels wide on Google Earth. Gives no information unless you say that the resolution is 1 pixel = X metres.
  • It is nice to know that it is only 1/2 pixel or whatever number of pixel, but how about a real size ? in kilometers ?
    • Re:Size (Score:5, Informative)

      by helioquake ( 841463 ) * on Wednesday April 12, 2006 @03:26AM (#15111848) Journal
      It can be derived with trigonometry:

          (angle)*distance_to_the_object == size_of_the_planet

      which are

          (1.5pixel*0.025"/pixel)/(60*60*57.3radian/") * 100AU * 1.5e8 km/AU ~ 2700km.

      If you read the article, you'll find that the size is only 1400km, though.
      The difference results from the fact that the measured size of 1.5 pixel
      includes the size of its point spread function for the HST/ACS/HRC (i.e.,
      even a true point source show some finite size in optics...something we
      cannot beat).
      • > It can be derived with trigonometry:

        But you still need the scale.

        > (1.5pixel*0.025"/pixel)

        So where'd you get the 0.025 from?
        Without that, 1.5 pixels is completely meaningless. a "pixel" could be any size
  • by mrjb ( 547783 ) on Wednesday April 12, 2006 @03:09AM (#15111794) a link to the image?
  • Excellent (Score:3, Informative)

    by Burb ( 620144 ) on Wednesday April 12, 2006 @03:12AM (#15111802)
    As every Dr. Who fanboy knows, the tenth planet is named Mondas. []. What is slashdot coming to?
  • Kill Xenu? You can't say that about my religion! I'm gonna sue you! I'll see you in court!
  • by Vellmont ( 569020 ) on Wednesday April 12, 2006 @03:20AM (#15111828) Homepage
    It's because the word planet isn't really a scientific word. There's no hard point where something becomes a planet and where it's not a planet. Words like planet are really just our own convienent language definitions. Arguing about whether something is a planet or not is a little like arguing whether something is a chair or not. It only matters based upon useage.
  • Why is this so hard? (Score:4, Interesting)

    by jpatters ( 883 ) on Wednesday April 12, 2006 @03:36AM (#15111879)
    I don't understand why this is so hard to understand. The only sensible definition for a planet is an object that is spherical due to its own gravity, orbits a star, and is not itself a star. But these bozos keep saying "But Pluto is so different from the other planets, we can't call it a planet!" Well boohoo. So it's freaking different! Earth and Jupiter are somewhat freaking different from each other, last time I checked, but we call both of those objects planets! "But then there will probably be a thousand planets in the solar system!" they say. I say, get over it! This is not a big problem unless you're an astrologer! I honestly don't give a rat's ass about Pluto's legacy as being called a planet, if we are going to continue calling it a planet then we also need to call this other object (and several others) planets as well. The problem is, we keep being told that this needs to be controversial because defining a planet is somehow difficult, what I think is happening here is that there are a group of scientists who have an emotional problem with there being a thousand planets in the solar system and are preventing the IAU from adopting the obvious definition.
    • The following joke just came to mind...

      Your momma is so big and so cold they launched her into space and couldn't figure out if she was a planet or not!

      OK, that was a crappy joke.

      I'd have to agree with the "no 1000 planets, please" antagonists. Defining Kuiper belt objects as planets demotes the concept of "planet". We might as well call every object that orbits the sun "space thing" and be done with it.
    • by jmv ( 93421 )
      The only sensible definition for a planet is an object that is spherical due to its own gravity, orbits a star, and is not itself a star

      OK, so any mass of liquified gas orgiting the sun would qualify, right? How about comets (if they are spherical)?. Oh and how about we say the moon is orbiting the sun and the Earth is just going around it?
      • Well, for one, comets are not spherical - and a comet's coma is not spherical due to gravity, which is almost non-existant from an object the size of a comet's nucleus... So we can scrap comets from your list.

        The moon : wel just claiming the moon orbits the sun and the earth is going around it is nice for you, but that doesn't make it true... The center of gravity of the Earth-Moon system is *inside* the Earth and the Moon orbits the Earth. - So we can scrap the moon from your list...

        Now, Jupiter and Saturn
    • By that definition, Ceres, the largest and first discovered asteroid, is a planet. See: []

  • The Plan (Score:3, Funny)

    by suv4x4 ( 956391 ) on Wednesday April 12, 2006 @03:36AM (#15111882)
    NASA secretly discovers disturbing facts about the nature of the tenth planet, and decides the news is too shocking for the wide audience. A plan is created to announce the news in several manageable bites:

    1. tenth planet not as big as previously thougth, it's more like a small planet, but hey it's a still a friggin 10-th planet, right!

    2. tenth planet not a planet as previously thougth, it's more like a moon of Pluto.. but it's still a friggin planet, if not THE 10-th planet...

    3. new moon not really a moon, turns out it's more like a really big meteor, so big, it's kinda as big as a moon, almost, but not exactly...

    4. big meteor kinda smaller than big, more like, medium meteor, still there though! xena, the medium meteor!! Yei!

    5. ok maybe it's not that of a medium, more like a small meteor, little warrior meteor thingy.

    6. hey what did you know! that little meteor thingy noone really friggin cares about, was a smudge on the Hubble lens system! huh, sh*t happens, but it's not like we confused it to be the 10-th planet in the Solar system, I mean, cut us some slack, come on :)

    7. hey watch us drink cola in zero gravity. wobble, wobble, wobble, wobble!! lol!
  • Stupid name (Score:5, Informative)

    by Kirth ( 183 ) on Wednesday April 12, 2006 @03:39AM (#15111890) Homepage
    Well, what kind of a name should that be anyway? Xena is not a roman god or goddess, not even a small one like Luna, Nike or Pluto.

    So if this object should be called a planet, here's the proper list of names to choose from:

    Acca Larentia, Alemonia, Anna Perenna, Carmenta, Carna, Consus, Dea Dia, Feronia, Flora, Fons, Furrina, Maia, Nike, Ops, Pales, Pomona, Portunus, Robigus, Silvanus, Veiovis, Vertumnus, Volturnus

    everything else is not acceptable.
    • Re:Stupid name (Score:4, Insightful)

      by mgblst ( 80109 ) on Wednesday April 12, 2006 @03:54AM (#15111936) Homepage
      How about this line from the article
        Nicknamed "Xena," 2003 UB313 was discovered last year.
      So 2003 UB313 was discovered last year, in 2005 - doesn't that strike someone as a little odd.
      • Well I'll be damned, you're right. When I read "discovered last year" in the article, I naturally assumed that Slashdot had posted another 2 year old story as "news," but according to the story's date it's current. Good catch.
    • Re:Stupid name (Score:3, Informative)

      by renoX ( 11677 )
      Why wouldn't it be acceptable?
      Why should planets/asteroids only be named after gods?

      IMHO Xena is a name that more people know that all the name you gave, so it's easier to remember thus it's a better name.
    • Xena is not a roman god or goddess

      Well, Xenia is one of the many epithets for Athena (so, Minerva, if you want the Roman corruption). From 'xenos', probably referring to her hospitality related "duties".

      Incidentally, how did you pick your "proper list" from the hundreds of Roman deities? (Nike is the Greek form btw, Victoria is the Roman equivalent)

    • Re:Stupid name (Score:3, Interesting)

      by TrevorB ( 57780 )
      IIRC, the discussions at the astronomical society have come to the conclusion that most of the good roman names have been used up. They're talking about moving into other pantheons for names (Hindu I believe was considered).

      It better be a big set of names if we're going to start naming all the large Kuiper belt objects we're going to find.
    • everything else is not acceptable.

      Heh, now a Slashdotter made this unintentional imitation of the comic book guy in Simpsons again. ;-)
    • AFAIR Romans had so many deities, covering nearly every aspect of their life, that the above list would be far too short.
    • Xena is not a roman god or goddess, not even a small one like Luna, Nike or Pluto.

      I think Xena and Buffy are prefectly fine names. The Roman-God names are just drawn from the fictional mythology of the era in which many of the planets were discovered. I think the silliness that we may associate with Xena and Buffy is merely the same silliness and unimaginitiveness that many medical terms would have if we translate them literally into English.

      Also, the discoverers wanted to use a name that started with 'X'
    • Erm, no. (Score:3, Funny)

      by Just Some Guy ( 3352 )

      ...the Roman goddess of bleeding men dry. I'm not divorced, but I think my less fortunate brethren might want to skip over this one.

    • by fbg111 ( 529550 )
      Ah, should have named it Xenu. We could have had a great joke at Scientology's expense...
  • Wrong end? (Score:3, Funny)

    by ozmanjusri ( 601766 ) <(moc.liamtoh) (ta) (bob_eissua)> on Wednesday April 12, 2006 @04:40AM (#15112048) Journal
    The Tenth Planet Shrinks Under Hubble's Gaze

    I bet they're looking at it through the wrong end of the telescope. If they turn Hubble around, that thing'll turn out to be HUGE!

  • I've been reading a book recently (The Geography of Thought) on the differences between how Western and Eastern people think. One of the main theses in the book is that Western thought (since ancient Greek times) is oriented toward objects and their classification, whereas Eastern thought (since ancient Chinese times) focuses more on continuous substances and the relationships between them. Another thesis (or corrolary of the previous one) is that Western thought avoid contradictions, whereas Eastern though

    • I read a treaty by an eastern philosopher who correctly stated that the "both-and" arguement model necessarily contains the "either-or" model, though the opposite is not true. doesn't help.

      What that translates to in this case is that not classifying it to accept both conditions (planet and non-planet) is a classification in and of itself - as "unclassified". Either it's classified or its not. See how the either-or emerges?

      This is a simplification of the argument, but the gist of it is that the Ea
  • by bloodstar ( 866306 ) <> on Wednesday April 12, 2006 @05:44AM (#15112232) Journal
    From TFA:

    The reasons are simple. Even Mike Brown says there is no scientific basis for calling 2003 UB313 a planet. Here is what he said last year:

    I will not argue that it is a scientific planet, because there is no good scientific definition which fits our solar system and our culture, and I have decided to let culture win this one.

    He's using Mike Brown's acceptance of the generally accepted cultural view that planets are 'anything pluto sized or larger' as a way of discrediting 2003 UB313. In fact, Mike Brown had felt previously that the definition of Planet was unsatisfactory and threw out some ideas on how the definition could be altered. l#planets [] links to the text in question. Mike Brown has since come to the conclusion that culture is going to decide what defines a planet, not a bunch of scientists. So basicly, unless the scientists who want to change the definition of a planet can convince society to listen, it's going to be like a tree falling in a forest with no one around to hear it. Sure, it happened, but who cares?

  • New images of 2003 UB313 (aka Xena) were delivered by the Hubble Telescope and showed up as only 1.5 pixels!"

    ... it was soon after discovered that according to current theories, moving closer to the 10th planet would make it show up as 3 pixels, and even 6! Scientists worldwide are baffled at this discovery, and one was quoted as "if we send out a space probe far enough, it could even cover an entire screen of several Megapixels". This claim was however met with scepticism, with many still claiming that th

  • Sounds like its time for a lynching.
  • How does one display "half a pixel"?

    I'm guessing greyscale, but still the idea of half a pixel strikes me as somewhat funny.

    ps. Kudos to the person who posted the "." as a substitute for a link to the image. You made my day.
  • by aplusjimages ( 939458 ) on Wednesday April 12, 2006 @08:57AM (#15112810) Journal
    According to the TV show CSI, they can take that pixel increase the image size and then enhance it enough to make out all the different geographical terrian on the planet/object in space. I tried it in Photoshop and it just doesn't work.
  • i disregard what something orbits in my home cooked scheme:
    • anything earthlike (small, mostly solid, sphere, appreciable atmosphere): planet

      that means mercury is not a planet. but titan is
    • anything like the moon (small, mostly solid, sphere, no atmosphere): moon

      that means mercury is a moon. so is pluto. so is ceres
    • anything like jupiter (huge, mostly gas): gas giant, enough said
    • anything like phobos/ deimos (small, nonspherical, all solid): asteroid
    • then you have the comets (small fragile compacts of dust a

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