World Clocks News Today

It's a complicated situation that involves physics, global power politics, climate change, technology and two types of time.

The hours and minutes that dictate our days are determined by Earth’s rotation. But that rotation is not constant; it can change ever so slightly, depending on what’s happening on Earth’s surface and in its molten core.

Apple has finally migrated the Clock app to the Mac with the arrival of macOS Ventura. Here is how to use the Clock app on your Mac, and what you can do with it.