Spheres of Influence: A Collection of Spherical Sites

Dylan Thuras is a guest blogger on Boing Boing. Dylan is a travel blogger and the co-founder of the Atlas Obscura: A Compendium of the World's Wonders, Curiosities, and Esoterica, with Joshua Foer.


Recently the most perfect spheres in the world were created as an answer to the "kilogram problem." Made to replace a chunk of platinum and iridium that has defined how much a kilogram weighs for 120 years (the weight of the metal has been changing ever so slowly ) the spheres are about the size of a melon and almost perfectly round. They are likely the most perfectly spherical objects on the planet.

"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"

With this in mind we present you a collection of a few of the more interesting spheres found around the world.

Sweden Solar System: The world's largest model of our planetary system centered around the largest spherical building in the world.

The Mapparium: An three story inside-out glass globe built in 1935.

The Sudbury Neutrino Observatory: A gigantic spherical neutrino detector built into the largest man made underground cavity in the world.

Costa Rican Stone Spheres: Mysterious spherical rock formations from an earlier era.

Paris Sewer Museum: Giant wooden balls helped keep the Parisian sewers clean.

The Republic of Kugelmugel: A spherical "micro-nation" in the heart of Vienna.




  1. Saying “the weight of the metal has been changing ever so slowly” is not exactly correct.

    The kilogram still weights one kilogram– By definition.

    Even if seems absurd, it’s more correct to say that it is everything else that’s slowly changing weight.

  2. The problem is not that the kilogram doesn’t have the same mass, it’s that the reference kilo -housed in a chateau outside of Paris- has changed in mass with respect to the average of a dozen others just like it around the world. The difference is about fifty (50) micrograms. They were all made at approximately the same time and of the same material. Scientists who have been studying this issue for more than sixteen years -yes, it’s not news- are puzzled as to why this is happening. European scientists have been working on the new reference kilos mentioned in the post -which is made from Silicon-28- for over three years now. Here’s a story from Faux News from September of 2007:


  3. A little more info please – where are those new reference spheres being created, who’s saying that pull-quote, etc.?

  4. #7 – The spheres were created by the CSIRO’s Australian Centre for Precision Optics, a government funded body here in Australia.

    There’s a fair bit of info around about the project, but the CSIRO press release is probably a good start.

  5. I can understand why they went with a sphere as it minimizes surface area and absolutely minimizes edges. But Oskay above raises an interesting question. How did they determine that the statndard kilogram was changing its mass as opposed to oh, anything else they were measuring against it?

  6. And, sorry, Falcon Seven, but I just don’t accept Fox News as a source for facts about this universe.

  7. #16 – Overwhelming common sense indicates that it’s the kilogram that’s changing mass with respect to the average mass of its first-generation copies, but since the unit is defined with respect to that artifact, it’s really only correct to say that the mass of the other objects– as measured in kilograms — is changing.

  8. The project to define Avagadro’s number in terms of a fixed number of silicon-28 atoms is worth a look, also.

    We have a small sample ultrapure silicon-28 in Oxford for nuclear / electron resonance experiments – a neat side-effect of the extreme purification required to get the mass of the sphere right is that the few remaining impurities are so well isolated from each other that they display quantum coherences lasting seconds (!)

  9. DREW #10
    I think Gravity Probe B deserves mention for sure (Probe homepage at Stanford) but I imagine the new roundest spheres beat its quartz/niobium ones by dint of having been made more recently. The explanation on that page of the way those gyroscopes work is pretty mind-blowing; they take advantage of zero-viscosity Helium-III and superconductivity to maintain their accuracy.

  10. My bad – I was going from memory on Gravity Probe B. They don’t use Helium III for suspension; they electrically levitate the spheres in a vacuum. The engineering section of that website is fascination multiplied by awesome, by the way.

  11. @4:
    It doesn’t seem like it. Their scale sun is a 37m (what? tall? diameter? circumference?) observatory dome, while the Swedes use the 110m diameter Globe hall.

    This also fits with the Australian Pluto model being “less than 200km away”, while the Swedish one is about 300km distant.

  12. @18 Wrap your mind around this as a possible cause (sixteen (16) years ago) -your favorite morning stimulant may be needed:


    This may be considered as more ‘reputable’ than Faux News, but lay reporting just the same -also six years old.:


    Also covered on the most reputable source ever -nearly two years ago:


  13. If the “blown up to size of the earth” info is correct, this would make it not only the roundest, but perhaps more remarkably, the SMOOTHEST.

  14. must say, this is certainly a ballsy post comments collection, some fascinating stuff in all the links above, do explore them.

  15. Another candidate for the most spherical objects on Earth are the targets hit by Lawrence Livermore Lab’s $2B laser. When the laser hits, the outside layers expand, flying outward and creating pressure on the inside, hopefully enough pressure to start a fusion reaction. But if the target isn’t round enough, the insides will just sorta squirt out one side before enough pressure builds up.

    “To meet NIF specifications, these shells must be no more than 1 micrometer, or a millionth of a meter, out of round; that is, the radius to the outer surface can vary by no more than 1 micrometer (out of 1,000) as one moves across the surface. Solving this extremely difficult problem will require significant improvements in current micro-encapsulation technology.” — https://www.llnl.gov/str/Letts.html

  16. a neat side-effect of the extreme purification required to get the mass of the sphere right is that the few remaining impurities are so well isolated from each other that they display quantum coherences lasting seconds (!)

    So that’s how a Palantír works.

  17. Once upon a time (1977), a professor at the university where I work developed a process for creating perfectly round and uniform spheres.
    They were at one point (though possibly not today) the most perfect spheres man could create.
    They are manufactured under the name Dynabeads today.

  18. @26:
    On one hand, their reference sun is just 36 feet – almost exactly a tenth of the Swedish one.

    On the second hand, you are of course, per definition, right.

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