Quantized space as a result of loop quantum gravity

Post by **Martin Blank** » Thu Dec 18, 2003 10:30 pm

There's an article in the current issue of SciAm that presents a concept so simple that it should be intuitively obvious, and yet it's not. Whether it's a result of the way I was taught, or that the two concepts are equally acceptable, I'm not sure, but here's the gist of it:

Space is normally perceived to be smooth and continuous, like a smooth cloth. But what if it's not? What if there exist discrete packets (or quanta) of space? These quanta (as explained in the article) would be about 10^-33cm long, or 10^-99cm in volume. Travel would involve jumping between these quanta, much like the way that electrons jump through energy states.

And why not? Matter is quantized (molecules -> atoms -> particles -> quarks -> maybe strings); energy is quantized (photons); time is quantized (Planck time, or about 10^-43s); so why shouldn't space be quantized?

If time is quantized, then something traveling at a given speed can only move at a specific speed in one Planck time. To be measured between the two points, it would have to be measured in less than one Planck time, which is not possible. Therefore, it jumps from location to location, which is most easily explained by quantizing space, because then it cannot physically exist between two quanta and must jump from location to location. A mathematical link between the two would be more useful, but I think this would work out.

This seems to me a better unification of concepts, and may lead to a better mathematical understanding of the universe. Quantizing space may also significantly simplify models that were approximations before by allowing the use of discrete numbers in calculations. Since the models would have used modeler-specified data points anyway, there may not be many changes to the model, but they can go from averages to specific numbers at the data points, and anytime you can do this you get better models.

Teranfirbt · Post by **Teranfirbt** » Thu Dec 18, 2003 10:34 pm

buh buh buh.... ok, whatever you say..

Blokeymon · Post by **Blokeymon** » Thu Dec 18, 2003 11:17 pm

You lost me at "There's an article...."

Prospero · Post by **Prospero** » Thu Dec 18, 2003 11:42 pm

Just to give some "visual representation" of Planck length, if you put a string the size of Planck length next to a meter stick, the stick would have to extend to the size of the visible universe in order to show the string as the size of a small tree. The numbers are so infintesimally small that I gave up thinking about it long ago. Theoretical physics "ain't my bag, baby."

Also, haven't people written about space been quantized before? (graviton?)

Dr. Tower · Post by **Dr. Tower** » Thu Dec 18, 2003 11:49 pm

Hmmmm, need to gets me an account on SciAm. Anyway, this is quite interesting, and would definately help to explain why the speed of light is the fastest possible. But I have some other questions about this, would the quanta of space be constant? The energy levels for an electron are based on the type of atom. Would it not make sense then that the space quanta are based on the medium? This would also explain why light moves slower in mediums other than a vacuum (the index of refraction of a material is the ratio of how fast light moves through a vacuum relattive to it).

Also, at 10^-33 cm, that would be 10-35 m, Planck's constant is 6.626068 × 10-34 m^2*kg / s, which basically means even if we could measure something's position down to that level, we wouldn't be able to know the momentum to within 10 kg*m/s, which is quite a large momentum for the particles that are as small as we would be talking about.

Prospero · Post by **Prospero** » Fri Dec 19, 2003 12:22 am

Towerboy... give me your bwains!

/me makes the 'bwains' face.

Rorschach · Post by **Rorschach** » Fri Dec 19, 2003 12:24 am

[quote="Blokeymon";p="241492"]You lost me at "There's an article...."[/quote]
Yup
I'm off to bang two rocks together
/me feels stoopid

Killer-Rabbit · Post by **Killer-Rabbit** » Fri Dec 19, 2003 12:36 am

[quote="Towerboy";p="241505"]Hmmmm, need to gets me an account on SciAm.[/quote]

Your college/university library might have electronic access to it.

Pout · Post by **Pout** » Fri Dec 19, 2003 2:02 am

Also, at 10^-33 cm, that would be 10-35 m, Planck's constant is 6.626068 × 10-34 m^2*kg / s, which basically means even if we could measure something's position down to that level, we wouldn't be able to know the momentum to within 10 kg*m/s, which is quite a large momentum for the particles that are as small as we would be talking about.

Yeah but since when has modern physics been about being practical.

Prospero · Post by **Prospero** » Fri Dec 19, 2003 2:39 am

I have the equation of the T.O.E.

It's..

Code: Select all

x = x; where x != x

That solves everything.

Dr. Tower · Post by **Dr. Tower** » Fri Dec 19, 2003 2:53 am

[quote="Killer-Rabbit";p="241522"][quote="Towerboy";p="241505"]Hmmmm, need to gets me an account on SciAm.[/quote]

Your college/university library might have electronic access to it.[/quote]
I'll look into that, however I am at home on break for my winter vacation, so I may check when I get back.

Edit: Oh yeah, and Glue, I would prefer to keep my bwains, sorry.

JudgeMental · Post by **JudgeMental** » Fri Dec 19, 2003 2:58 am

You know what would rock? If in the end, we managed to come up with a G.U.T. that ended up with some form of 42 as the answer...

Anyway, this thought doesn't come as a surprise to me. I've often wondered if space is granular in such a respect. Theoretical physics is very fun.

Oh, and Rorschach, I suggest you decrease the angle of impact by at least 15°. That SHOULD get you a spark... That is flint, right?

Dr. Tower · Post by **Dr. Tower** » Fri Dec 19, 2003 3:48 am

Meh, the answer is always 42, you just have to change the units you're using.

Mr.Shroom · Post by **Mr.Shroom** » Fri Dec 19, 2003 5:46 am

Isn't this Fotini's work? I can never remember her damn last name. She's one of the new up-and-coming young physicists of the past few years, and quite the looker, to boot. And I'll confess, its ALOT easyer to handle mentally than string's explanations.

Edit: Ah, same site had something on her. And its free.

Fotini Markopoulou Kalamara. Say THAT five times fast. Has more details, and a bit of background.

Dr. Tower · Post by **Dr. Tower** » Fri Dec 19, 2003 8:02 am

That article was quite interesting indeed, and I would have to agree with the conclusion that she is a looker.

I'm guessing the dispersion effect that it mentioned near the end may be because wavelengths of photons may have to be integer multiples of the quantized space, though I must admit that that happens to be throroughly unfounded speculation on my part. However, if that is the case, is there then an upper limit on frequencies of radiation that can be created, above which they actually get "aliased" down due to the quantization of space?

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