# Smallest Delta T?

1. Feb 11, 2006

### Mattara

This question could have been posted in qm or gsr but since it is so versitile i'll post it here.

Is there a smallest $$\Delta T$$?

ex.

year => minutes => seconds => atto seconds etc.

2. Feb 11, 2006

### rbj

some might have speculated that the Planck Time

$$t_P = \sqrt{\frac{\hbar G}{c^5}} \approx 5 \times 10^{-44} \mbox{s}$$

or somewhere in the ballpark, but don't ask me to justify it.

3. Feb 12, 2006

### Mattara

from http://en.wikipedia.org/wiki/Planck_time :

/../The Planck time /.../is the "quantum of time", the smallest measurement of time that has any meaning/../

/.../we can neither measure nor discern any difference between the universe at the time it first came into existence and the universe anything less than 1 Planck time later./.../

So there isn't a smallest $$\Delta T$$ only a smallest period of time during which something might actually happen i.e. everything below Planck time is to small for anything to happen (complete a cycle from being unfinished to being finished)?

Last edited: Feb 12, 2006
4. Feb 12, 2006

### Meir Achuz

Wikipedia is worth what you pay for it.
"This is the "quantum of time", the smallest measurement of time that has any meaning." is just speculation with no foundation.

5. Feb 12, 2006

### Mattara

So then what is Planck time and is there a smallest $$\Delta T$$?

6. Feb 12, 2006

### Claude Bile

There is no evidence as far as I'm aware, that time is quantised, thus from our current understanding, there is no smallest dt.

Claude.

7. Feb 13, 2006

### rbj

yeah, that should be fixed. the Planck Units article doesn't have that speculation in it, but others have disagreed with the section on invariant scaling of nature.