# Ian Robinson

National Physical Laboratory (NPL)

Mass and engineering team

Hampton Road, Teddington, Middlesex, TW11 0LW NPL

Articles: “Towards the redefinition of the kilogram”

Homepage

Twitter. With Klaus von Klitzing, NPL

Wikipedia: The Kibble balance

YouTube

## “*…redefine the kilogram in terms of a fundamental constant.*“

First email: Saturday, 21 September 2019 @ 4:17 PM

Dear Dr. Ian Robinson,

Out of a high school in New Orleans — https://81018.com/home/ — we followed embedded geometries back to the Planck scale, and then out to the approximate size of the universe using base-2 (doublings) of those Planck natural units. It was a geometry class. We were just following a simple logic, talking about Zeno and anticipated hitting the Planck Wall at some point. We thought it would take thousands of steps. In 45 we were down to the CERN scale in particle physics, and in 67 more steps we hit the wall. Going larger was equally dramatic. In just 90 steps, we were out to the current expansion. Finally, here was a visceral grasp of exponentiation.

202 doublings — https://81018.com/chart/ — from the smallest to the largest! “Isn’t it fascinating?”, we thought.

We did that in December 2011 and I put it out for other schools as a fascinating STEM project. Feedback has been slow and tentative. I also started asking my more academic friends, even a few scholars, “Where is this information on the web? Who are the experts? What does it mean? Does it have anything to do with cosmology? …ontology? …particle physics?”

To help calculate the approximate size of the universe, we used the Hubble telescope’s data and had some help from a NASA scientist — https://81018.com/2012/06/14/kolecki/ — and from a French astrophysicist. As a result of those discussions, we asked NASA’s Joe Kolecki if we might compute the meter using the Planck Length. That’d be quite a standard! The reading closest to the meter would be 2-to-the-115 which corresponds to 0.67 meters and 2-to-the-116 corresponds to 1.35 meters. A standard could use one or the other or get as accurate as you want by taking a fractional that brings it equal to 1.

It didn’t take long before we suggested the same for Planck Time to define the second, Planck Mass to define the kilogram, and Planck Charge to define the Coulomb.

Are we just being silly?

Is the entire concept silly?

We’ve all gotten much older now and

being silly doesn’t look good. Can you help us?

Thank you.

Most sincerely,

Bruce