Chandra X-ray Observatory - HomeAbout The ChandraEducational MaterialsField GuidePhoto AlbumPress RoomResources
Chandra X-ray Observatory - HomeChandra Resources - You are here
ObservatoryMultimediaImages and IllustrationsAnimations and VideoChandra Special FeaturesChandra PodcastsPresentationsVirtual PostcardsHandouts and ActivitiesDesktop ImagesScreen SaversAudioQ&AGlossaryAcronym GuideFurther Reading
Web Site ToolsVisit the Chandra ChroniclesEmail NewsletterSite MapNew & NoteworthyImage Use PolicyQuestions & AnswersGlossaryDownload Guide

Q&A: General Astronomy and Space Science


Q:

My friend believes that the universe is only 6000 years old. As proof of this he says the rotation of the Earth is slowing one second a day. If you add one second a day for every day from today back to the dinosaurs, the rotation would be so fast the dinosaurs would not survive. Is the Earth really slowing? If so, how does science disprove the rest of this logic?

A:

The length of the day varies for many reasons -- ocean tides, atmospheric circulation, internal effects, which are cyclical or random, and the transfer of angular momentum to the Moon's orbital motion, which causes the length of the day to increase by about 1.5 - 2 milliseconds per century.

Extrapolating back to the time of the dinosaurs about 100 million years ago, the length of the day would have been about 2000 seconds shorter. Still plenty of time for a dinosaur to find a meal and get a good night's sleep, I would imagine.

Reference:
http://maia.usno.navy.mil/eo/whatiseop.html.

Back | Index | Next

separator line
CXC Home | Search | Help | Site Map | Image Use Policy | Privacy & Accessibility | Downloads & Plugins
Latest Images | New & Noteworthy | Multimedia | Flash Ecards | Glossary | Q&A | Guestbook


RSS Feed RSS Feed | Podcast Podcast | Blog Blog

[News by email: Chandra Digest]
[Contact us: cxcpub@cfa.harvard.edu]
NASA's Home Page Smithsonian's Home Page CXC Home Page Image Map for NASA's, Smithsonian and Chandra's Home Pages
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, Cambridge, MA 02138 USA
Phone: 617.496.7941 Fax: 617.495.7356


Text Size:
normal font large font larger font
Chandra X-ray Center, Operated for NASA by the Smithsonian Astrophysical Observatory
This site was developed with funding from NASA under Contract NAS8-03060.
Revised: August 02, 2005