Time - continuous or quanta?

[fls]

I first stumbled across Loop Quantum Gravity in Scientific American. I find that to be a decent bridge between reputable journals and comic books!

Honestly, for the little physics I know, once I wanted to step beyond SciAm, I had to go to textbooks (and available professors and... you know... a university education ).

I agree. I am not without any of the above.

fls: please comment in my other thread. It would be great to get more ideas on the subject!

I already know that my ideas on the subject are highly unpopular, and I'm not sure I have the fortitude to defend them at the moment.

Linda

 

[fls]

It's the same concept with the time idea. Since there is a minimum "distance" across which we can measure with any meaning--the universe's "maximum resolution", for shorthand--and a maximum speed--c--we end up with a minimum time.

If you read through the link that Yllanes provided (thank you Yllanes!), the "loop representation" approach does not depend upon this issue, even though it also converges onto the same answer.

Linda

 

[Hellbound]

fls:

Yeah, well, I warned you all

I hadn't looked through it, actually. I don;t do too much in-depth research except mayber on weekends (I post from work, a few minutes here and there isn't much, but I can't spend a half-hour reading ).

I need to read up on some of the loop gravity theories; I have a decent layman's understanding of string theory, M-theory, the stanbdard model, and relativity...and know enough about QM not to make nonsensical statements like "QM proves my cat can read the minds of telporting aliens using healing crystals", so learning a bit about this would be interesting. I also want to see if this is actually a different derivation or if it boils down tot he same thing at the lowest level (i.e.-it's based on uncertainty principles or something similar). I'm curious now, dang you!!

I'm billing you for my time spent reading about this, now

 

[Cuddles]

Time equals distance divided by speed, right? So the shortest time that is measurable would be the shortest distance divided by the fastest speed. As I understand it, the shortest distance it is possible to measure in any way whatsoever is the Planck distance (something x 10^-34 metres), and the fastest speed is 3x10^8 m/s, that of light in a vacuum. So the smallest time unit is the first (very small) number divided by the second (very big) number, to give you a very small fraction of a second.

Or is it that the wrong way round?

Ah, but the problem here is that you are considering time and space to be two seperate things. Your post is correct in that if space is quantised, time is also quantised (and vice versa), however the "if" is really the question at hand. Answering the question of the quantisation of time by postulating the quantisation of space doesn't actually answer the question, it simply shifts it to a question about the quantisation of space.

The answer to that question is the same as I said in my last post, we think it is but we really don't know and aren't sure how we could find out.

 

[IXP]

Bascially, we're fairly sure it's quantised, but the energies required to test it are so much higher than we can reach that it might not ever be possible for us to actually know for sure.

A theory based on quantization, though, might predict measurable results that differ from non-quantized space/time. If confirmed, this would be strong evidence that it is quantized.
IXP

 

[TheDon]

I'm pretty sure it's called the space-time continuum in Star Trek.

 

[Soapy Sam]

Quanta - but there can be only one.

 

[Ivor the Engineer]

A related question to the OP is can two or more events occur at the same time?

 

[Broes]

Well, we already know that energy and space (distance) is quantified.

Might be reasonable to assume time also is quantified...

 

[Cuddles]

A theory based on quantization, though, might predict measurable results that differ from non-quantized space/time. If confirmed, this would be strong evidence that it is quantized.
IXP

True, but as it stands at the moment, no theory makes a prediction that can be tested in the forseeable future.

Well, we already know that energy and space (distance) is quantified.

No we don't. We know that if space is quantised, time must be quantised, and vice versa. However, we don't actually know if either one is.