Roundest objects in the world created

but... why.....................

Greater accuracy than any of the tools on YouTube

The first one was used in a gyroscope of a spacecraft, I think.

I'll bet good money that at a microscopic level the surface looks like a mountain range.

I bet you would be wrong.
After months of sanding, the team produced two spheres with diameters of 93.75 millimetres. The mass of each sphere matches that of the Australian copy of the kilogram. The small-scale roughness of the balls varies by only 0.3 nanometres, and their curvature by 60 to 70 nanometres.
"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."

Yeah....apparently this guy hasnt even been in a high accuracy measurement class....We use guage blocks that are ground so smooth that temporary bonds form in between flat surfaces...Id be willing to bet that if they made a half of a mirror of the sphere...then place the sphere inside...They wouldnt even be able to seperate them after. Molecules actually get ground down at this accuracy.

Hey jgrimmier if your comment is directed toward me, you are way off base. I am a Journeyman Machinist. I am aware of the ability of a Jo Block to be wrung together and have the blocks stick together. I have worked with quart optical flats and air gauges. None of us have worked down to a nanometer. Nanometer = one billionth of a meter.

they should try making the most triangulest triangle in the worl next

I've seen rounder.

Because they can.