Q:Can you explain science like your "The Second" post. How do scientists prove that counting radiation from Caesium is an accurate way to measure time? I'm always baffled by these extraordinary claims because I have no clue how they come to these conclusions. Help Science Guy!
Scientists started having doubts that the orbit of the Earth was a good basis for the measurement of time. For us, it works fine, but when you get down to the superfine time measurements of things like GPS systems, you need to be incredibly accurate. There’s no room for error.
Now we use atomic clocks to define a second. And since other measurements like volts rely on the second, they are based on this too.
In most of the world, atomic clocks use cesium-133, a stable form of cesium with 55 protons (and electrons) and 78 neutrons. When cesium atoms are bombarded with microwaves (video here), some of them get excited and give off energy as a result of “excitation state” changes. Since energy exists as a wave, we can measure the wavelength of it. One second is defined as 9,192,631,770 cycles of that wave radiation, just like you’d picture in an oscilloscope.
Now, I’m not a physicist, so if I messed this up, someone can correct me.
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