The second will go from 9 billion vibrations to a trillion or more this decade

A second is a date, something we agree on: it’s a second. “However, this appointment ran into some problems with our modern technology,” Scheire said.

“In fact, you could start by saying, ‘What is a day?’ Noon to noon is 24 hours, then you divide that into minutes and seconds, so you can define a second as the nth part of a full day.The problem is that our measurements are now so good that they have been able to see for a long time that day length is not constant.Earth actually spins a little slower all the time, after all we are slowed down by the ebb and flow and by the moon.

“It’s very minor,” Scheire admits, “but the result would be that if you stick to that definition, a second in a hundred or a thousand years will be longer than our second today. And you don’t really want that. , because in physics wants to be able to consider a second as the disintegration time of an atom.”

“There’s a lot of physical processes that need that second, without it changing over time, so in the 1950s they said, ‘Okay, redefinition, now we’re going to look at the vibrations of outgoing radiation. a cesium atom can come. This thing is vibrating it has a frequency of about 9 billion times per second and that’s as far as we know pretty much constant across the universe and all the time so we’ll just define the second like 9 billion. a little more of those vibrations of radiation from the cesium atom.”