What Happens Beyond the Planck Length?

The Planck Length is a mysterious constant in modern physics which is often credited as being the smallest allow length in nature or a sort of resolution of the Universe. In reality, this length is derived from considering a particle who’s reduced Compton wavelength is comparable to its Schwarzschild radius; the first being an idea from Quantum Mechanics and the other a concept from General Relativity. We will see from this definition that the Planck Length is a scale where both QM and GR effects are important – the scale at which Quantum Gravity dominates! This can be seen in the formula for the Planck Length which includes Planck’s Constant, Newton’s Gravitational Constant and the constant Speed of Light in a Vacuum.

Theories such as M-Theory and Loop Quantum Gravity attempt to explain such regimes, but at present neither are confirmed. This does not prevent us from using other physics to gain insight at to what could be happening at the Planck Length. It is likely that it is the smallest radius a black hole can have and the scale at which every fundamental force of nature becomes unified. We have already shown how the Electromagnetic and Weak Nuclear Force become unified into an Electroweak force, and Grand Unified Theories (GUTs) include the Strong Nuclear Force in another unification. When the Universe was less than 1 Planck Length in diameter, or less than 1 Planck Time old, it will have had such a high temperature that every fundamental force, including gravity, could have theoretically been unified. As it expanded and cooled, spontaneous symmetry breaking occurred, splitting the forces into the 4 we experience today – however a theory which models how a completely unified force behaves is needed to understand what happens on the Planck Scale.

This video discusses the real meaning and derivation of the Planck Length and Planck Scale and discusses what might modern physics believes happen at and beyond those scales using insight from Particle Physics and General Relativity.

0:00 - Planck Length as a Universal Resolution?
0:34 - Deriving the Planck Length; The Physical Insight
1:07 - Quantum Mechanical Part: Compton Wavelength
2:33 - General Relativistic Part: Schwarzschild Radius and Gravity
3:26 - The Planck Length: A New Regime?
4:02 - Quantum Gravity and Black Hole Considerations
4:44 - Fundamental Force Unification and Symmetry Breaking
5:41 - Early Universe and the Planck Epoch
6:31 - Do Not Think Classically or Quantum Mechanically at this scale

[martinrumsey]

What happens beyond the Planck length? My wife said, you end up in the sea....every pirate knows that.

[RomanNumural]

Thank you for not pulling any punches. Straight and directly to the point. So many other videos would try to describe this with 25 minutes of preamble. This is nice

[SpaceCakeism]

Saw the title, saw the duration; thought to myself, "try me."
Glad I did, didn't expect to find this gem; getting tired of hearing the same few lines regurgitated thousands of times, so this was a breath of fresh air.

[KippiExplainsStuff]

I'll tell you why I love your videos: as a science communicator myself (longform text), I disagree with the tendency of most pop sci channels to disrespect the readers/viewers by dumbing things down or glossing over important science. if you respect your viewers enough to explain it clearly without dumbing it down - you're doing it right.
good job, my friend. love your content!

[thebaryonacousticoscillati]

I've read many different explanations/descriptions of this but I have to say the way you've presented it has given me a totally new way of thinking about it. Very much appreciated!

[julianemery]

I liked how you explained this.
It feels like you had the brief of "Whats the fewest words needed to explain this without cutting corners or dumbing down?" And you stuck to it quite well.

[brucea]

I'm glad you clarified that things can still happen below the Planck length. I also like that you suggested a minimum nonzero radius for a black hole. Although I think most physicists suspect a black hole doesn't really have zero radius I find in many discussions of black holes they claim it does have zero radius. I wish they would state what they believe instead of misleading people. I also dislike the habit many people have of referring to a black hole's size as the size of its event horizon. A black hole is actually much smaller than that.

[thejorgelopez]

This channel is gonna sky rocket any day now. Some of the best explanations and visuals of complex topics I’ve ever seen. This thing is about to take off. Congrats.

[nicemandan]

I'd always imagined the planck length/scale as a universal voxel but thanks to this explaination I now realise this is not the case.

[MisakaMikotoDesu]

Thank you for this! This is very insightful compared to what you get with other channels.

[seanspartan]

I just found this channel and I can't believe there are so few subscribers. The material and presentation reminds me of PBS Spacetime. I especially like that information and even complex concepts are explained succinctly yet I don't feel like they're being "dumbed down."

[zxLoneWolf]

Cohesive and aesthetically pleasing format. Concise information. Great video

[Slowpaws]

Good work, I usually watch these videos right after popping in a suppository. It is very calming.

[Rationalific]

Thank you for this video (and others that I'll check out later)! Please keep up the great work! I just subscribed, and I hope MANY more do as well in short order (even if not quite within the sub-Planck time...).

[Elrond_Hubbard_]

I'd heard of a Compton wavelength before but I didn't really know what it was, so thank you for teaching me that and more!

I did a BSc but not in physics. I am a huge fan of these topic though, and I consider myself to have an advanced level of a layman's understanding. I really like that your video isn't pulling any punches because that's how I learn new things.

Liked and subbed. Can't wait to see your channel grow mate 😊👍

[anthonydraco]

Thank you for explaining this clearly. Planck units has never made sense to me until you. It’s always been to me they just pluck random numbers and shuffle them around in the least understandable way to get them. NOW I understand why they’re the smallest units that matter.

[enlongchiou]

Joseph Polchinski string theorist proposed at Planck length l=g*m/c^2=(h*g/2pi*c^3)^0.5 which can deduce vacuum energy under critical mass[6^3*pm] is solution of GR field equation can expand to proton scale pl=g(p)*(4pi*pm/3)/c^2 generate strong force by Tesseract which can transfer into EM force between proton[pm], electron[me] in Atom[A] by which can reproduce Dirac's quantum field, deduce - : discrepancy of muon magnetic moment of (g-2)/2 factor between experiment data, theoretical prediction from Fermilab at 8/10/23.

[martifingers]

Remarkably well done. Simple as possible - but not too simple as Einstein advised! I have immediately subscribed.

[durandalgmx]

Very deep but very enlightening. My perception of the universe is changed yet again. Thanks.

[Chatsworth]

Excellent vid! Amazing that we can even begin to consider such processes with our finite minds.