rotation. Here’s the puzzle: That is about 6 minutes, or one percent, longer than the radio rotational period measured by the Voyager 1 and Voyager 2 spacecraft, which flew by Saturn in 1980 and 1981.

Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes and 4 seconds with respect to other distant stars. Scientists call this difference crucial to ...

Astronomers have found that the rotational profile of a nearby star, V889 Herculis, differs considerably from that of the Sun. The observation provides insights into the fundamental stellar ...