James Vincent

And that eventually became what is officially known as the Système International or the SI, which has a lot of more units in it, but it's basically the metric system. And these units used to be based on physical standards. There was a kilogram, there was a meter. So everything, every unit in the world, every kilogram in the world was, technically speaking, a copy of this physical kilogram.

And that eventually became what is officially known as the Système International or the SI, which has a lot of more units in it, but it's basically the metric system. And these units used to be based on physical standards. There was a kilogram, there was a meter. So everything, every unit in the world, every kilogram in the world was, technically speaking, a copy of this physical kilogram.

And it was a small little weight made of platinum iridium alloy, about the size of a hen's egg, very small because the metal is so dense because it's meant to be unchanging over time.

And it was a small little weight made of platinum iridium alloy, about the size of a hen's egg, very small because the metal is so dense because it's meant to be unchanging over time.

And it was a small little weight made of platinum iridium alloy, about the size of a hen's egg, very small because the metal is so dense because it's meant to be unchanging over time.

and they kept it in a vault underground vault near Paris in Versailles and they had two of them over the centuries and then in sort of the middle of the 20th century they discovered that the most recent one which is known as the international prototype kilogram was losing weight and it wasn't losing much weight it was losing about 50 micrograms which is about the weight of a single eyelash

and they kept it in a vault underground vault near Paris in Versailles and they had two of them over the centuries and then in sort of the middle of the 20th century they discovered that the most recent one which is known as the international prototype kilogram was losing weight and it wasn't losing much weight it was losing about 50 micrograms which is about the weight of a single eyelash

and they kept it in a vault underground vault near Paris in Versailles and they had two of them over the centuries and then in sort of the middle of the 20th century they discovered that the most recent one which is known as the international prototype kilogram was losing weight and it wasn't losing much weight it was losing about 50 micrograms which is about the weight of a single eyelash

But in the sort of the high precision world of scientific metrology, the science of measurement, it's pretty consequential. So what they did is that they redefined the unit. So it's no longer based on a physical object, but it's based on universal constants, in this case, quantum constants. So these are sort of calculations or figures that we think are unchanging throughout reality.

But in the sort of the high precision world of scientific metrology, the science of measurement, it's pretty consequential. So what they did is that they redefined the unit. So it's no longer based on a physical object, but it's based on universal constants, in this case, quantum constants. So these are sort of calculations or figures that we think are unchanging throughout reality.

But in the sort of the high precision world of scientific metrology, the science of measurement, it's pretty consequential. So what they did is that they redefined the unit. So it's no longer based on a physical object, but it's based on universal constants, in this case, quantum constants. So these are sort of calculations or figures that we think are unchanging throughout reality.

So, for example, the meter used to be based, as the kilogram was, on a physical standard. And eventually they found that this was too imprecise. So they moved it to this sort of definition based on the distance traveled by light. So it's essentially it's tied to the speed of light.

So, for example, the meter used to be based, as the kilogram was, on a physical standard. And eventually they found that this was too imprecise. So they moved it to this sort of definition based on the distance traveled by light. So it's essentially it's tied to the speed of light.

So, for example, the meter used to be based, as the kilogram was, on a physical standard. And eventually they found that this was too imprecise. So they moved it to this sort of definition based on the distance traveled by light. So it's essentially it's tied to the speed of light.

So this is sort of the big project of the System International, of the metric system, is that over the centuries, they started off as physical standards, and they've all become these standards based on universal physical constants. And the idea is that by doing that, the units become unchanging.

So this is sort of the big project of the System International, of the metric system, is that over the centuries, they started off as physical standards, and they've all become these standards based on universal physical constants. And the idea is that by doing that, the units become unchanging.

So this is sort of the big project of the System International, of the metric system, is that over the centuries, they started off as physical standards, and they've all become these standards based on universal physical constants. And the idea is that by doing that, the units become unchanging.

So they're based on the speed of light, they're based on the spin of atoms, they're based on things that we think are the same throughout the universe.

So they're based on the speed of light, they're based on the spin of atoms, they're based on things that we think are the same throughout the universe.

So they're based on the speed of light, they're based on the spin of atoms, they're based on things that we think are the same throughout the universe.