Go to Home Page
You are here
Go to Reference Section
Go to Directories Section
Go to Community Section
Go to Fun Section
Go to Science Store
Go to About PhysLink.com
Top Destinations Menu
 Ask the ExpertsAsk the
Experts

 Physics Job BoardPhysics
Job Board

 Physics and Astronomy Departments DirectoryUniversity
Departments

 FREE Einstein eCardsEinstein
eGreetings

 PhysLink.com Science eStoreScience
eStore


Local in California?
Visit one of our retail stores.
XUMP - Science Toys





Win an Apple iPod Touch 32GB! Or one of Einstein Stuff Packs worth over $50! Enter our Einstein Look-a-Like Photo Contest! Click here for more details.

   Question

What is Planck length? What is Planck time?

Asked by: Adam Faust

Answer

The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the ‘quantum of length’, the smallest measurement of length with any meaning.

And roughly equal to 1.6 x 10-35 m or about 10-20 times the size of a proton.

The Planck time is the time it would take a photon travelling at the speed of light to across a distance equal to the Planck length. This is the ‘quantum of time’, the smallest measurement of time that has any meaning, and is equal to 10-43 seconds. No smaller division of time has any meaning. With in the framework of the laws of physics as we understand them today, we can say only that the universe came into existence when it already had an age of 10-43 seconds.

Answered by: Dan Summons, Physics Undergrad Student, UOS, Souhampton


go to the top  
All rights reserved. © Copyright '1995-'2008 PhysLink.com
Win an Apple iPod Touch 32GB! Or one of Einstein Stuff Packs worth over $50! Enter our Einstein Look-a-Like Photo Contest! Click here for more details.