## A question about Planck length and Planck time

Discussions concerned with knowledge of measurement, properties, and relations quantities, theoretical or applied.

### A question about Planck length and Planck time

If I convert one second of sidereal time into Planck time, then convert 299 792 458 meters into Planck length, why dont I get identical answers? There are clocks now, that are so accurate, that one meter of length can be given as a time (when using the speed of light as a common denominator.) So why don't the numbers add up, when the distance that light travels in one second is calculated in planck units ? I Have always been under the impression that the laws of physics hold true, right down to the Planck length, which is obviously wrong. Could somebody clarify this problem for me? If one Planck length is the distance light travels in one Planck time, surely
the total units in each measurement should be the same?
curiosity
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### Re: A question about Planck length and Planck time

Mind showing us your calculations?

BioWizard

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### Re: Whine or Wiki?

curiosity wrote:one Planck length is the distance light travels in one Planck time

1 Planck length is 1.616199 x 10-35 meters.
1 Planck time is 5.39116 x 10-44 seconds.

Dividing the two gets you 0.2998 x 109 m/s or about 300,000 km/sec. (i.e. c).
You're off to a good start!
c should be 1 in Planck units, right?
1 ÷ 1 = 1. It's intended to make things easier!