measuring unit from which all else is derived. ——- 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.

measuring unit from which all else is derived.

——-
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.

—–

“Photon epoch” is the very start of our observable Universe.

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http://medipix.web.cern.ch/ is at the heart of scientific photon counting and imaging.

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Want your own photon detector for radiation detection? Their Timepix created by the collaborative can do that, along with mapping high energy particle collisions, like a mini LHC on a USB stick.
 
https://www.youtube.com/watch?v=L42EQ2w_fuk
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Ah. Here Zee Zee
 
 
Single photon uses. One of them is establishing and maintaining Quantum Standards.
 
Keeps theory from getting too whack.
 
via: https://www.spiedigitallibrary.org/journals/optical-engineering/volume-53/issue-08/081910/Metrology-of-single-photon-sources-and-detectors-a-review/10.1117/1.OE.53.8.081910.full?SSO=1
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Ooh, this is the answer!
 
“Using the largest allowed value for the photon mass from
other experiments, we find a lower limit of about 3 yr on
the photon rest-frame lifetime. For photons in the visible
spectrum, this corresponds to a lifetime around 10
18 yrs.
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 “Because of the time-dilation effect predicted by Einstein’s special theory of relativity,

a billion billion years on Earth feels like only three years to a photon, because it’s traveling so fast.”

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