Editing Sphere (section)

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File:Einstein gyro gravity probe b.jpg|An image of one of the most accurate human-made spheres, as it [[refraction|refracts]] the image of [[Albert Einstein|Einstein]] in the background. This sphere was a [[fused quartz]] [[gyroscope]] for the [[Gravity Probe B]] experiment, and differs in shape from a perfect sphere by no more than 40 atoms (less than 10{{Spaces}}nm) of thickness. It was announced on 1 July 2008 that [[Australia]]n scientists had created even more nearly perfect spheres, accurate to 0.3{{Spaces}}nm, as part of an international hunt [[Alternative approaches to redefining the kilogram#Alternative approaches to redefining the kilogram|to find a new global standard kilogram]].<ref>[https://www.newscientist.com/article/dn14229-roundest-objects-in-the-world-created.html New Scientist | Technology | Roundest objects in the world created].</ref>
File:King of spades- spheres.jpg|Deck of playing cards illustrating engineering instruments, England, 1702. [[King of spades]]: Spheres
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