by Estelle Asmodelle
![Neptune Neptune](http://www.cosmosmagazine.com/files/imagecache/news/files/news/20110704_Neptune-features_web.preview.jpg)
TUCSON: The first accurate measurement of Neptune’s rotational period has been determined by tracking specific atmospheric features. A day on Neptune lasts precisely 15 hours, 57 minutes and 59 seconds.
This finding adds to our knowledge of the fundamental properties of Neptune and also provides a mechanism for understanding how Neptune’s mass is distributed. The study could lead to a better understanding of the giant gas planets in general.
http://www.cosmosmagazine.com/news/4474/neptunes-day-measured