From the National Institute of Standards and Technology website:
In November 2018, the world’s measurement experts are expected to revise the SI, this time approving a system that does not depend on physical objects. Instead, it’ll be based entirely on the speed of light and other “constants” of physical science, resulting in a measurement system that might truly and finally be for all times and for all people.
These constants are central to a set of well-established scientific principles. They are the backbone of our ever-expanding knowledge of natural laws, such as Einstein’s well-known E = mc2 , which describes how mass and energy behave throughout the universe.
These scientific principles are the same ones we’ve already used to create a modern world where we watch flat panel TVs, navigate deep space and explore quantum computing. And this revised measurement system promises to help lead to technological innovations we cannot yet imagine.