It's a compass, a clock, a calendar and a ruler all rolled into one! For stargazers, the Big Dipper is a celestial compass, clock, calendar and ruler. Here’s how to use it. : Read more ...

Sky Shorts: Nature's calendar, compass and clock in the night sky. ... So, image Polaris as the center of the clock and the Big Dipper is the big hand which circles counterclockwise around Polaris.

The most detailed look yet at the monarch butterfly’s built-in clock suggests it’s an ancient model. The molecular mechanism that keeps the day-night rhythm in the butterfly’s brain shares ...