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Roundest Object In the World Created 509

Posted by CmdrTaco
from the boobs-boobs-boobs dept.
holy_calamity writes "An international research group has created the most perfect spheres ever made, in a bid to pin down a definition of the kilogram. It should be possible to count exactly the number of atoms in one of the roughly 9cm silicon spheres to define the unit. Currently the kilogram is defined only by a 120-year-old lump of platinum in Paris, but its mass is changing relative to copies held elsewhere. Other SI units have more systematic definitions."
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Roundest Object In the World Created

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  • Wishing... (Score:4, Funny)

    by AioKits (1235070) on Tuesday July 01, 2008 @09:20AM (#24014621)
    Did anyone else read "An international research group has created the most perfect spheres ever made" and think boobs?
  • by elrous0 (869638) * on Tuesday July 01, 2008 @09:20AM (#24014627)
    No mere human will never be able to accomplish what God did with Jennifer Lopez's ass.
    • by Anonymous Coward on Tuesday July 01, 2008 @09:28AM (#24014727)

      In a press release today, Sir Mix-A-Lot is quoted as saying that, by viewing this object, "You get sprung", as well as "[wanting to] pull up tough" because of the perfect shape of the object.

      He was later quoted as saying that "I like'em round and big, And when I'm throwin a gig, I just can't help myself". Clearly, he is an aficionado for perfectly round objects.

      * my captcha was "beating", which is what I deserve for the 90's reference.

    • by Sabz5150 (1230938) on Tuesday July 01, 2008 @09:45AM (#24014935)

      No mere human will never be able to accomplish what God did with Jennifer Lopez's ass.

      Perhaps not, but we are interested in pinning down the exact measurement of the kilogram, not the metric ton.

      • Re: (Score:3, Funny)

        by hey! (33014)

        This thread is like a couple of janitors on break discussing the merits of the 2008 models according Yachting magazine.

        They might have the dinghies, but they'll never use them with the objects of discussion.

  • anyone (Score:3, Insightful)

    by gEvil (beta) (945888) on Tuesday July 01, 2008 @09:21AM (#24014635)
    Does anyone here want to inform CmdrTaco that boobs shouldn't be perfectly spherical, and in fact, it's preferable if they're not?
  • Finally (Score:5, Funny)

    by Rik Sweeney (471717) on Tuesday July 01, 2008 @09:22AM (#24014647) Homepage

    No one will be able to claim that a game of pool, snooker or soccer was won because the ball wasn't round enough...

  • What's the problem? (Score:4, Interesting)

    by Dolda2000 (759023) <fredrik@dolda2000 . c om> on Tuesday July 01, 2008 @09:25AM (#24014687) Homepage
    I've never really understood the problem with creating a more stringent definition of the kilogram. Other SI units are measured in measurable quantities, such as the second being defined in terms of cycles of radiation from Caesium atoms. Why cannot the kilogram just as easily be defined as the mass of a certain number of atoms of one or another kind?

    Of course, I'm no experimental physicist, but if I were to guess, I might suggest the fact that the binding energy (and thus the mass) might change with force-field fluctuations in the vicinity, but I think that problem should be solvable by defining the proper environment for measuring.

    Does anyone know?

    • by joaommp (685612) on Tuesday July 01, 2008 @09:31AM (#24014771) Homepage Journal

      That's precisely what they are trying to do.

    • by Zironic (1112127) on Tuesday July 01, 2008 @09:31AM (#24014773)
      That is what they are doing. They are defining the kilogram as X silocon atoms.
      • by clickety6 (141178) on Tuesday July 01, 2008 @10:39AM (#24015741)

        That is what they are doing. They are defining the kilogram as X silicon atoms.

        Oh God! We're back to the earlier boobies thread again...

    • by icegreentea (974342) on Tuesday July 01, 2008 @09:34AM (#24014833)
      You can define a kilogram in the number of atoms of X element, but you still need a physical object to calibrate your scales against. In this case, I believe they did it by number of silicon atoms. TFA says they went and milled a silicon sphere (purified to only Silicon-28) weighing as close to the current standard as they can get it. Next they're going to measure it (X-rays and the such) to find the density, spacing, and the such and end up getting a number of silicon atoms. This number will now BE the kilogram, and these spheres are going to be the new physical standards. They are suppose to be an improvement in that is it theoretically possible to recreate these spheres should anything happen to them (as we know the amount silicon needed), while it is not possible to recreate the current standards.

      My other summary was a bit off, got the process a little backwards.
      • by MrNaz (730548) on Tuesday July 01, 2008 @10:19AM (#24015467) Homepage

        It's not totally worthless, as the kilogram is the basis for just about all other SI units. It is the only unit that is not defined according to other units, or in relation to a natural property. Thus, its definition is arbitrary, and everybody must agree as to what a kilogram is before the unit has any value as a standard. There's a very nice explanation of the kilogram as a fundamental unit here:

        http://en.wikipedia.org/wiki/Kilogram#Importance_of_the_kilogram [wikipedia.org]

      • by phobos13013 (813040) on Tuesday July 01, 2008 @10:20AM (#24015471)
        We are getting measures mixed up here; they are not measuring the number of atoms for the kilogram, as that is not a measure of mass. They are measuring the number of atoms to make Avogardo's constant exact and tying it to the kilogram! They will define a specific number of atoms in a certain amount of the substance then saying that the kilogram is defined as the mass contained in X number of atoms!

        In fact, this change in the kilogram is coupled with a change in avogadro's constant to make one immutable and the other exact!
    • Re: (Score:3, Interesting)

      by nkh (750837)
      Where I was studying a few years ago, I had a teacher who was working with a french laboratory to create a standard for the kilogram. It was supposed to work with a machine to record the pressure applied to it (some kind of scale as far as I understood) and a bunch of lasers to measure everything. It was the first and only time I've heard about someone trying to standardize the kilogram.
    • by Anne_Nonymous (313852) on Tuesday July 01, 2008 @09:48AM (#24015003) Homepage Journal

      A kilogram is defined as exactly 2.20462262 pounds of pure water at pressure of 100 kPa (1 bar) and a temperature of 273.15 K. :)

    • by Moraelin (679338) on Tuesday July 01, 2008 @09:56AM (#24015117) Journal

      Well, it's sorta like this: a standard is only useful if you have some effective way to reproduce it or measure with it.

      1. time. You can essentially just make a MASER, which means basically a cavity which resonates at that frequency. The nice part is that it can be tuned, and even continuously tuned, by just measuring the amplitude of the signal. When you've reached the maximum power, the thing is tuned to that frequency.

      2. length. It's measured by Interferometry, so you have a meaningful way to transform a wavelength into any given distance.

      At any rate, the transition for these two only happened when someone build a device which could actually measure one second or one metre that way.

      3. mass. Well, that's the tricky one. Saying that you define a kilogram as one bazillion silicium atoms is useless unless you can somehow actually produce a lump with that many atoms. As long as we can't actually be sure how many atoms are in there, it would be a useless standard.

      These guys claim to have been able to do just that: say with a high degree of confidence that, yep, their spheres contain exactly that many atoms. If they're right, then we're finally ready to move the kilo to that standard.

    • Re: (Score:3, Informative)

      I've never really understood the problem with creating a more stringent definition of the kilogram.

      Others have pointed out that they are doing more or less what you advocate, but let me address the more general issue.

      Remember that the definitions for the fundamental units are intended, above all, to be *practical*. In other words, the goal is to make the definition as easy as possible for a competent scientist/engineer anywhere in the world to reproduce in order to calibrate some instrument. All the funda

  • Cleanroom? (Score:5, Insightful)

    by lobiusmoop (305328) on Tuesday July 01, 2008 @09:26AM (#24014705) Homepage

    The picture in the article shows the sphere being handled in what obviously isn't a cleanroom. Won't that mess up its surface?

  • Pong (Score:5, Funny)

    by The Crooked Elf (1042996) <peppe@cs. u s m . maine.edu> on Tuesday July 01, 2008 @09:28AM (#24014735) Homepage
    In other news... these same scientists are hosting the BEST GAME OF PONG EVER this weekend!
  • Metric... (Score:5, Funny)

    by jo7hs2 (884069) on Tuesday July 01, 2008 @09:30AM (#24014753) Homepage
    So the metric system, which is touted as being so much more accurate than the measurements we here in the U.S. know and love is has a measurement that is based on a disappearing lump of metal? The only logical conclusion one can draw from this disclosure is that the metric system is magic, and should be burned at the stake.
    • by gardyloo (512791) on Tuesday July 01, 2008 @09:43AM (#24014919)

      Perhaps it's due to the changing masses of ducks? I'm just sayin'...

    • Re:Metric... (Score:5, Interesting)

      by odourpreventer (898853) on Tuesday July 01, 2008 @09:52AM (#24015055)

      It gets worse. US standards are based on metric standards. (For instance, the inch is defined as 25.4 mm.) You're basically using a French system!

  • by Anonymous Coward on Tuesday July 01, 2008 @09:36AM (#24014847)

    So I'm not getting fatter, it's the kilogram that's getting slender!

  • by intx13 (808988) on Tuesday July 01, 2008 @09:40AM (#24014903) Homepage

    An international research group has created the most perfect spheres ever made, in a bid to pin down a definition of the kilogram. It should be possible to count exactly the number of atoms in one of the roughly 9cm silicon spheres to define the unit.

    "First we create a perfect sphere, then we count the number of atoms exactly - and we get a kilogram standard!"

    "Alright... so how big do we make this sphere?"

    "Oh you know.. roughly 9 cm, give or take."

  • just add water (Score:5, Interesting)

    by krystar (608153) on Tuesday July 01, 2008 @09:46AM (#24014949)
    why not just define a kg as 1 Liter of pure H2O at 4deg C?....it is that way anyway.
    • by pimpimpim (811140)
      so the kg will change depending on the current atmospheric pressure?
    • Re:just add water (Score:5, Informative)

      by Shados (741919) on Tuesday July 01, 2008 @10:10AM (#24015331)

      Because its 1 liter of pure h2o at 4 deg C -at the sea level-, (remember, pressure isn't the same at the top of a mountain than it is at the bottom...and it changes everything). It is also not universal... if the earth was to go boom, (and somehow live), we'd lose our reference.

      That is in opposition to, let say, a meter, which is a fraction of the distance light travels in a specific amount of time. Fairly universal. (I beleive it USED to be a fraction of the earth's size... which was quite bad too).

      • Re: (Score:3, Funny)

        by nEoN nOoDlE (27594)

        if the earth was to go boom, (and somehow live), we'd lose our reference.

        I think in that case, we're gonna have other things to worry about than knowing the exact measurement of 1kg

  • pi (Score:4, Funny)

    by oni (41625) on Tuesday July 01, 2008 @09:46AM (#24014965) Homepage

    Does this also pin down the value of pi? I mean, they know exactly how many silicon atoms are on the surface of the sphere, and they know exactly how many atoms there are from the center to the surface.

    hmm.

  • by Rinisari (521266) on Tuesday July 01, 2008 @09:49AM (#24015015) Homepage Journal

    The roundescht object in the world isch your mother, Trebek.

  • I think that Gravity Probe B has the most perfect spheres and they are much smaller that the Kilogram sphere.

    Kilogram Silicon Spheres
    "If you were to blow up our spheres to the size of the Earth, you would see a small ripple in the smoothness of about 12 to 15 mm, and a variation of only 3 to 5 metres in the roundness"

    Gravity Probe B Spheres
    http://www.nasa.gov/mission_pages/gpb/index.html [nasa.gov]
    "If these ping pong-sized balls of fused quartz and silicon were the size of the Earth, the elevation of the entire surface would vary by no more than 12 feet"
  • by carlcmc (322350) on Tuesday July 01, 2008 @09:59AM (#24015159)
    They should have visited this guy's website

    http://www.kyokyo-u.ac.jp/youkyou/4/english4.htm?

    making spherical mud balls. I've had this bookmarked in del.icio.us for a long time
  • by Memetic (306131) on Tuesday July 01, 2008 @10:24AM (#24015543) Homepage Journal

    ...has created the most perfect spheres ever made...

    ...roughly 9cm...

    That precise eh?

  • Simple (Score:4, Funny)

    by readin (838620) on Tuesday July 01, 2008 @11:41AM (#24016621)
    Just define the KG in terms of pounds at 1 G. Do Americans have to solve all of France's problems for them?
  • by boristdog (133725) on Tuesday July 01, 2008 @12:06PM (#24017023)

    The answer is none.
    None more round.

  • by fo0bar (261207) on Tuesday July 01, 2008 @12:28PM (#24017347)

    It's 1024 grams, right? Easy definition.

  • by Dylanesque (868329) on Tuesday July 01, 2008 @01:44PM (#24018737) Homepage
    I am a physicist at the UK's National Physical Laboratory and I am involved in the redefinition of another unit - the unit of temperature. The work concerning the redefinition of the kilogram is >much more philosophically fraught and technically difficult. I understand many of the rather skeptical comments expressed here The current situation is unsatisfactory because the mass of the kilogram is changing, albeit by a small amount - a few micrograms in 1 kg - i.e. a few parts in 10^9. The aim of the work is to replace this artefact with (essentially) a procedure. Effort onne (using the silicon sphere) is essentially trying to build a link between a macroscopic mass, and the microscopic masses which we expect to be fixed. The other effort not mentioned here is called the watt balance which is a machine which can exhibit the same inertial mass as a kilogram - or any other weight. At the moment the two watt balances disagree with each other and they both disagree with the silicon sphere result. There is still a lot of work to do on both approaches. Incidentally, the reason is it is a sphere rather than a cube is because of edges. Edges are amazingly fragile, hence the sphere. ALl the best M

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