You are downloading:
| The first accurate atomic clock was built in 1955. Since when the second being based on atomic time and defined as the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two levels of the caesium atom. |
| Copyright © 2009 Liquid Mirror Enterprises. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Liquid Mirror Enterprises is strictly prohibited. Use of this site subject to Terms and Conditions. Privacy Policy |