# Textbook talks about Planck time

1. Sep 15, 2008

### Kudo Shinichi

A section in my textbook talks about Planck time, but I still don't quite get what does it mean after I finished reading it. I am also wondering whcih laws of physics can be applied to the Planck time.
Some info that might be helpful for answering this question:
tp=√(Gh/c^5)
where G is the gravitational constant, h is Planck's constant, and c is speed of light.

Thanks

2. Sep 16, 2008

### Defennder

Re: Help!!!

What do you need to understand about Planck time? It's just defined as the amount of time a photon would take to cover a distance equivalent to the Planck length.

See Wikipedia for details:
http://en.wikipedia.org/wiki/Planck_time

3. Sep 16, 2008

### Kudo Shinichi

Re: Help!!!

I am wondering which physics' law can be applied on the Planck time. Does gravitational law and law of refraction applied to the Planck time since Planck time is related to gravity as well as photon

4. Sep 16, 2008

### Kudo Shinichi

Re: Help!!!

I am wondering which physics' law can be applied on the Planck time. Does gravitational law,law of refraction and theory of relativity applied to the Planck time since Planck time is related to gravity photon
as well as speed of light