The most widely used atomic clocks use cesium atoms.

最广泛使用的原子钟使用铯原子。

When microwave radiation is humming at the exact right frequency, it does something special to cesium atoms.

当微波辐射以正确的频率震动时，它会对铯原子产生特殊的影响。

All that was left was to determine how many ticks of a cesium atom were in a second.

剩下的就是确定铯原子在一秒钟内有多少滴答声。

Cesium atoms oscillate at microwave frequencies, and are usually paired with a vibrating quartz crystal to keep time.

铯原子以微波频率振荡，通常与振动的石英晶体配对以计时。

So, you turn the dial on your little radiation machine until you hit the sweet spot that excites the cesium atoms, then you count 9,192,631,770 wobbles of that radiation.

所以，你转动你的小辐射机的表盘，直至到达激发铯原子的最佳位置，然后你计算 9，192，631，770 次辐射的摆动。

And so you tell the asteroidaliens that a day is - more or less - an invented time period that is 24 hours long, where each hour is 33 trillion oscillations of a special kind photon emitted by a cesium atom.

所以你可以告诉小行星外星人一天—或多或少—是一个虚构的时间段，其长度为24小时，其中每小时有33万亿个由铯原子发射的特殊光子振荡。