WHAT IS THE PLANCK CONSTANT?

The Planck constant, 6.62607015 × 10-34 kg m2 s-2, alongside other physical constants like the speed of light, is believed to be a fundamental property of the Universe that does not vary over time. The constant is used to calculate the amount of energy in a photon, by multiplying it by that photon’s wavelength. It’s named after Max Planck, a German theoretical physicist who won the Nobel Prize in Physics in 1918 for figuring out that energy comes in packets, or quanta, kick-starting the field of quantum mechanics. It’s taken years to measure it to the level of accuracy needed but that point was finally reached in 2017, making the kilogram’s new definition possible.