Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Sidereal Day 
Name: Tammy
Status: other
Grade: other
Location: NV
Country: N/A
Date: 1/25/2006
Question:
What is a sidereal day?

Replies:
A sidereal day is one 360 degree rotation of Earth. This is about 23 hours 56 minutes. Since our clocks are set to the position of the sun, we must turn just a bit more than this to have the sun once again line up with the meridian at noon. This rotation time, called synodic, for the sun to align to the same point in the sky takes 24 hours.

---Nathan A. Unterman


Click here to return to the Astronomy Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory