#Planck size

[vishumenon]

Against and For Evolution

WHY STATISTICAL MECHANICS NEGATES EVOLUTION Found on Facebook by Mark Champneys There are 3 billion base pairs in human DNA sequences. This is an arranged molecule of staggering size. The information content of DNA is rooted in the extreme improbability of those relatively few arrangements that code for life, in stark contrast to the vast number of possible sequence arrangements that are…

[dandelionsandderivatives]

"A little more of the same, Jane. What matter the planetesimal hypothesis or the quantum theory compared to such a dinner? Come, Jane, don't tell me you're ignorant of the quantum theory. A woman may get by without knowing about the planetesimal hypothesis but the quantum theory, Jane, is a necessity in any well-regulated household."

People are so very concerned with quantum mechanics in books written in the 30s.

I mean, I understand it was a very significant development at the time, but I'm still surprised that I've seen multiple novelists comment on it as a Significant Thing in the News.

[in-sightjournal]

Ask A Genius 1014: Quantum world informational fidelity shading

Rick Rosner, American Comedy Writer, www.rickrosner.org Scott Douglas Jacobsen, Independent Journalist, www.in-sightpublishing.com Scott Douglas Jacobsen: Have you ever seen a slider of an image enhancer? You can slide a vertical line left to right. It allows a before and after back-and-forth of the image, like a before and after acne treatment commercial or something. If Planck-scale quantum…

[webweabings]

GOD SAID, LET NEWTON BE! AND ALL WAS LIGHT

"Paul Davies; // Guy Kawasaki; // "Flammarion engraving", Unknown (1888); // "Portrait of Jean Mielot", by Jean Le Tavernier (1456); // "The New science: 3 complete works: Where is science Going?, The Universe in the Light of Modern Physics, The Philosophy of Physics", by Max Planck; // "Science, Philosophy, and Religion", by Albert Einstein; // Allan Sandage in "Sizing up the Cosmos: An Astronomer's Quest", interviewed by John Noble Wilford; // Louis Pasteur; // AWAKE experiment, CERN (2019); // Eckhart Tolle; // Voltaire; // "A Brief History of Time. ch 11", by Stephen Hawking; // St. John Cristal Casket; // Ralph Waldo Emerson; // Robert Winston; // "George Baker", Unknown artist (17th century); // "Cours de philosophie à Paris. Grandes chroniques de France", Unknown artist (14th century)

[yesterdays-xkcd]

The Planck length is another thousand or two pixels below the comic.

Depth [Explained]

Transcript

Title: Sizes Accurate on a vertical log scale.

[Series of images of characters doing various things. The things they are doing are listed in left to right order.] Cueball and Megan playing in a ball pen Megan using witchcraft to ban vista "Out, Vista!" Ponytail and Megan play Rock Band A couple is having sex under the cover in bed.

[Below this series of images, an image of a man on the computer.] Cueball is on a computer and the image expands as it goes down. Here are the labels from left to right, up to down: CD DVD Case North Bridge PS/2 Mouse (rodent) RAM CPU Socket Pin 32,767 Angels Dancing (one more and they'd roll over and become 32,768 Devils), Rice, Torrent (a bug), CPU, upcoming segfault dust mite hair OVUM Data (a pixel on Rick Astley's shoulder), rust mite, fork(); Peter Norton fighting a bacteriophage memory carbon nanotubes space elevator a line of silicon (Si), Electron Cloud, a man made out of arrows saying "sup?" silicon nucleus IPod femto Brian Greene knitting furiously [next to his knitting needles there is text saying ''clink, clink'']

[condoriano-67890]

Caesar Clown is made out of gas.

Which means no amount of gravity can affect him. My man could be on the surface of the SUN and still be floatin around like nothing’s wrong.

He can float through walls.. he can likely float through entire mountains. He could float to the top of Mount Everest and not be the slightest bit winded, or have broken the slightest sweat.

However… space is a vacuum.

Put Caesar in space? Caesar go BOOM! Annihilated.

I know he can control gas and all— he might try to pull all of his particles together while in space. He might be able to do it, although it would be extremely difficult without trying to accidentally become an entire planet in the process (yes, that is how they— and stars— form).

Caesar can become a planet.

Caesar can become a star.

Caesar can become a tiny galaxy.

(I’m having a million epiphanies right now. Give me a minute.)

Caesar can become a moon, or basically any kind of celestial object. AND, if he condenses himself densely enough, he can become a Planck-sized black hole (what is a Planck? I believe it is the smallest size of an object ever discovered.)

He can also probably change the type of gas he is. And, with his ‘final form’, we see that Caesar can collect other gaseous particles to absorb, to add onto himself, to make him bigger, and stronger.

Which means Caesar can become a supermassive black hole, or a laws-of-physics-defying monster of a planet.

Caesar’s Devil Fruit is incredibly underrated….

[mysticstronomy]

THE UNIVERSE COULD BE FILLED WITH ULTRALIGHT BLACK HOLES THAT CAN'T DIE??

Blog#400

Saturday, May 11th, 2024.

Welcome back,

Primordial black holes are hypothetical objects formed during the earliest moments of the universe. According to the models, they formed from micro-fluctuations in matter density and spacetime to become sand grain-sized mountain-massed black holes.

Although we've never detected primordial black holes, they have all the necessary properties of dark matter, such as not emitting light and the ability to cluster around galaxies. If they exist, they could explain most of dark matter.

The downside is that most primordial black hole candidates have been ruled out by observation. For example, to account for dark matter there would have to be so many of these gravitational pipsqueaks that they would often pass in front of a star from our vantage point. This would create a microlensing flare we should regularly observe. Several sky surveys have looked for such an event to no avail, so PBH dark matter is not a popular idea these days.

A new work, posted to the arXiv preprint server, takes a slightly different approach. Rather than looking at typical primordial black holes, it considers ultralight black holes. These are on the small end of possible masses and are so tiny that Hawking radiation would come into play.

The rate of Hawking decay is inversely proportional to the size of a black hole, so these ultralight black holes should radiate to their end of life on a short cosmic timescale.

Since we don't have a full model of quantum gravity, we don't know what would happen to ultralight black holes at the end, which is where this paper comes in.

As the author notes, basically there are three possible outcomes. The first is that the black hole radiates away completely. The black hole would end as a brief flash of high-energy particles. The second is that some mechanism prevents complete evaporation and the black hole reaches some kind of equilibrium state. The third option is similar to the second, but in this case, the equilibrium state causes the event horizon to disappear, leaving an exposed dense mass known as a naked singularity.

The author also notes that for the latter two outcomes, the objects might have a net electric charge.

For the evaporating case, the biggest unknown would be the timescale of evaporation. If PBHs are initially tiny they would evaporate quickly and add to the reheating effect of the early cosmos. If they evaporate slowly, we should be able to see their deaths as a flash of gamma rays. Neither of these effects has been observed, but it is possible that detectors such as Fermi's Large Area Telescope might catch one in the act.

For the latter two options, the author argues that equilibrium would be reached around the Planck scale. The remnants would be proton-sized but with much higher masses. Unfortunately, if these remnants are electrically neutral they would be impossible to detect. They wouldn't decay into other particles, nor would they be large enough to detect directly. This would match observation, but isn't a satisfying result.

The model is essentially unprovable. If the particles do have a charge, then we might detect their presence in the next generation of neutrino detectors.

The main thing about this work is that primordial black holes aren't entirely ruled out by current observations. Until we have better data, this model joins the theoretical pile of many other possibilities.

Originally published on https://phys-org.

COMING UP!!

(Wednesday, May 15th, 2024)

"DOES THE UNIVERSE EXPAND BY STRETCHING OR CREATING SPACE??"

[materialsscienceandengineering]

Advanced microscopy method reveals hidden world of nanoscale optical metamaterials

Scientists from the Department of Physical Chemistry at the Fritz Haber Institute of the Max Planck Society have made a significant discovery in the field of nanotechnology, as detailed in their latest publication in Advanced Materials. Their paper, titled "Spectroscopic and Interferometric Sum-Frequency Imaging of Strongly Coupled Phonon Polaritons in SiC Metasurfaces," introduces a novel microscopy method that allows for the unprecedented visualization of nanostructures and their optical properties. Metamaterials, engineered at the nanoscale, exhibit unique properties not found in naturally occurring materials. These properties arise from their nanoscale building blocks, which, until now, have been challenging to observe directly due to their size being smaller than the wavelength of light. The team's research overcomes this limitation by employing a new microscopy technique that can simultaneously reveal both the nano and macro structures of these materials.

Read more.

[simpsforscience]

Quiz time!⏱️ What's the smallest possible unit of length?🤔 Nanometer? Femtometer?.. Well, if this was your guess, we're afraid you're wrong.😅 Ever heard of the Planck length?🙄 That's the tiniest scale of nature, the size of the universe in Planck Era. Swipe through this post ➡️ to fathom how small this scale is! Join us on our series - 'Big Bang Theory'‼️ to know more such fascinating facts about the cosmos 🌠

📸Image credits:

Max Planck - Max Planck Gesselschaft

Alden Mead - University of Minnesota

[eightlivs]

A summary

So, the collider project was the crowning achievement of my career. (Still pissed about it getting blown up, but whatever, I can say that until I'm blue in the face.)

But fuck it, it still ran and it still gave me data and I'm still going to claim the results, so here goes.

...

...

Oh, wait, did you expect me to post my actual data?? HAHA NO. You're getting a summary, because I'll be damned if I post my actual data on a public-facing report log. Fuck you. Read about it in the paper I'll eventually publish, with my name on it. I am not going to let people just nick everything I've been working for.

But here you go. Things my collider has suggested or proved:

You can make micro black holes with as little energy as 9.4 tera-electronvolts (TeV) (aka, you can make them in a sufficiently powerful collider). (The LHC has a max design capability of 6.5 TeV per beam so far. My collider was supposed to start at 4.5 TeV and scale up to 8 TeV after upgrades (for a total of 16 TeV).)

Micro black holes exist. (These are just tiny, tiny black holes. They’re actually quite safe, so long as you aren’t standing near them. They pop into existence, then evaporate (see below) and disappear.)

There’s more than three spatial dimensions. (Also see here.) (Considering only three spatial dimensions, the “black hole threshold” is WAY too high, and you won’t be able to make a black hole of any size in a TeV-capable collider. The Planck mass (a natural unit of mass derived from only natural constants) is indicated to be a minimum limit on black hole masses - and the calculations just don’t allow black holes in the TeV range when using only three dimensions plus time. So, in order for black holes to be possible in the TeV range, you have to have a way to scale gravity in a way that’s stronger than in our three spatial dimensions. Otherwise, you won’t have the right conditions for a black hole. With more than three spatial dimensions (personally, I prefer M-theory, a version of string theory which favors ten spatial dimensions plus time), gravity can operate throughout ALL those dimensions, and can scale differently, lowering the “black hole threshold” into the TeV range.)

Gravity works in more than 3 dimensions. (In order for everything above to work, gravity has to permeate more than three dimensions in order to actually scale properly.) (Additionally, the fact that appearing and collapsing black holes can “grab onto” space enough to shred it indicates that gravity does indeed affect space itself.)

Black holes do indeed evaporate. (This has been accepted for a long time - Hawking proposed it in the 70’s, hence why it’s often referred to as Hawking radiation. The old idea that “nothing escapes a black hole”? That’s a trick statement, because technically, black holes DO radiate stuff, and lose mass and energy when they do. (hence the nickname “evaporation”). We’ve never had experimental proof of it before, but now, we know from looking at the data from the collider’s test runs that the micro black holes DID indeed evaporate and disappear in a flash of energy.)

More evidence that gravitons should be a thing. (String theories predicted a graviton, a subatomic elementary particle that regulates gravity.)

Warping space can shred the fabric of spacetime. (This is where the magic happens! The collider creates streams of micro black holes, which have gravitational pull and “bend” space a little bit. Then, the micro black hole disappears, and space snaps back. However, if you have a ton of micro black holes doing that, it’s pulling space in all sorts of rather violent directions all at once, and actually rips the space. That’s where the dimensional “portal” opens up.)

Space is, indeed, elastic to some degree - either that, or it can move fluidly enough that it looks like it’s healing the tears. (The dimensional “portals” were only open while the collider was on, and closed up when the collider turned off.)

Space DOES seem to have some form of “surface tension” or resistive buoyancy - possibly gravity? - that pushes back. (When the original Parker got pushed into the beam by Green Goblin, it took effort to hold him there, as if he were being pushed back.)

Parallel universes exist.

Different laws of physics exist in those universes. (This one’s a little bit less hard-proven and a little more “strongly suggested,” in that the spiders’ glitching seems to almost be on an atomic level, hinting at different underlying base physics.)

There’s some as-of-yet unnamed phenomenon which allows parallel-universe “versions” of a person to be summoned by throwing DNA into the collider beam.

I could think of more, but I think that’s enough stuff for today.

Footnotes: Hey folks! Long time, no see!

First things first, don't take anything here as truth. This is a lot more speculative fiction!

Second, I'm not starting this blog up again. I don't have the time for it - each post typically took days to weeks to research and write, even though they're short posts, and while I loved writing them, I just can't fit it in.

However, I found this in my drafts today - it's been sitting here since 2019! - and I'm not sure why I never posted it. It's something I remember putting a LOT of work into, though, and someone might find it interesting! I remember I wanted to list out possible things that Liv's collider experiments would have implications for, and there's a number of things here about the fictional collider's functions that I hadn't gotten to touch on.

Honestly, I don't thoroughly remember enough to vet the concepts fully as of today, but it's all fictional anyway. Like I said, don't take anything here as truth! If one could operate a collider like Liv’s, and get those particular results, then it’s POSSIBLE it would imply things, BUT in OUR universe, they haven’t been proven (and, again, I'm not a physicist! I'm a hobbyist armed with books and Google, and there's a high chance I've misinterpreted things here or there).

Citations are in-text as links.

Concepts that already existed: These are generally accepted as either a "thing" or "viable theory" by physicists. Micro black holes, Hawking radiation, more than 3 dimensions, gravitons, M-theory.

Concepts that already existed, but are kind of shaky: making micro black holes in a collider, parallel universes.

Concepts that I totally made up based on the movie (and thinking way too hard about things): shredding spacetime, space having surface tension, different laws of physics in parallel universes, the “as-of-yet unnamed phenomenon” of the last one.

Voilá! If anyone has questions about any of the science here, feel free to shoot me a message or an ask! I’ve tried pretty hard to include real-life info to build off of, and to clearly indicate what parts I’m just making up!

[penumbramewtwos]

I've been meaning to ask, are the armband controls on Okita to control her Dread Plate and Mind Plate implants?

The device(s) Okita wears on her arms are her own inventions. She's inquisitive by nature, and uses the device to help her usilise her telekinesis effectively, as well as for everyday life. She most likely stole a pokedex to make this

Okita struggles to use normal pokemon attacking moves, instead, over her lifetime she's perfected and refined her telekinesis down to the planck length, and manipulate quantum fields: i.e. She's able to use her telekinesis for alchemy, and roughly follows the alchemic laws of conservation and the first (irl) law of thermodynamics. 'Fun' fact: Instead of a Aura sphere, Okita creates appropriately sized black holes or pulsars with any matter around her to use as an attack. mangling her opponent. The only drawback, this attack can take up to a minute to prepare, leaving her vulnerable.

Thanks for the ask! @mel-the-pirate This was fun to answer ^^

[bpod-bpod]

Big Brained

Humans have the largest brain relative to their size of any creature, and the most complex with 100 billion neurons, each capable of having up to 15,000 connections. How our brains evolved that complexity wasn’t clear, but scientists have now identified a gene that might explain why. The gene called ARHGAP11B, is unique to humans and is crucial for the development of the neocortex – the brain region involved in higher-order functions like cognition and sensory perception. Studying how the neocortex evolved is challenging, but the development of organoid technology has opened doors. Researchers created ‘artificial brains’ from both human and chimpanzee stem cells. By adding ARHGAP11B to the chimpanzee brain organoids (areas highlighted in green), they found an increase in brain stem cells that drive growth and neurons involved with heightened mental capabilities. This suggests that ARHGAP11B played a crucial role in the evolution of the brain from our ancestors to modern humans.

Written by Sophie Arthur

Image from work by Jan Fischer, Eduardo Fernández Ortuño and Fabio Marsoner, and colleagues

Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in EMBO Reports, September 2022

You can also follow BPoD on Instagram, Twitter and Facebook

[tlaquetzqui]

In my SF future history, the UN has given way to the Alliance of Nations. It retains a lot of UN organs (the UN retains a lot of League of Nations ones), including the IMF. In my future it issues a currency, called the “right”, short for Alliance Drawing Right, derived from the IMF Special Drawing Right of our day. Since the government issuing it is the “AN”, and it’s the currency used by everyone, its symbol is the one used in logic for “for all”: ∀. (I think it was adopted partly in a situation analogous to the creation of the Allied Military Currency and Military Payment Certificates after World War Two: the AN having arisen to replace the UN for similar reasons to the UN replacing the League, namely a big fuckoff war the previous organization didn’t prevent.)

My main aliens, on the other hand, use what is technically a representative currency, like the gold standard, but based on an abstraction: the price of enough of an idealized animal fat (they’re obligate carnivores) to supply their metabolism with a given amount of energy. A hundredth of a Planck energy is about the daily calorie intake of a predator in the jaguar-to-tiger size range, like the aliens. (Unlike most Planck units, the energy one is huge: about 2 gigajoules, because the others are so small and there’s division involved.) I’m still trying to figure out what they call it, though—might just be the “energy, dietary”, and they just measure it in actual energy-units.

I think the aliens using, basically, calories-worth of lard, as a currency standard, grew out of similar causes to the aforementioned Allied Military Currency and Military Payment Certificates, but less catastrophic. Something like, people near the forts of the various empires accepted military ration points as legal tender, so those became a standard medium of exchange, eventually spreading over their world like the Spanish dollar. Obviously, of course, you aren’t originally measuring that directly in calories, but in volumes of fat—like how the productivity of a daimyō’s domain in feudal and shogunate Japan was assessed in units of koku (about 180 liters), generally considered the rice required to feed a person for a year.

[spacefaxbyaustin]

The Transformation of the Universe: From the Big Bang to a Cold Death

I really hope you enjoy this, even though it is very long for a blog. I would recommend reading until the end though, because I think the fate of the Universe is the most interesting part :)

THE START OF THE UNIVERSE- AKA THE BIG BANG

The Planck Epoch

Before the Planck Epoch, the universe was just a singularity at the beginning of time. The Planck Epoch is known as the first instant after the Big Bang, and scientists currently don’t know what happened in this period.

The Inflation Epoch

The Inflation Epoch took place from 10^-36 seconds after the big bang, where the universe expanded radically, from billions of times smaller than a proton to something between the size of a marble or a football field. In this period, scientists believe that gravity split from the other forces of nature, followed by the strong nuclear force. This triggered the universe’s short but rapid expansion, and this theory helps explain why the universe is smooth and flat. At this point, an immense amount of mass-energy came into existence, together with an equal, negative amount of gravitational energy.

The Electroweak Epoch

In this Epoch, which occurred 10^-32 seconds after the big bang, huge numbers of quark and antiquark pairs formed from energy, just to annihilate back into energy again when they met. Gluons, and some of the other more exotic particles, also appeared during this period. The universe was thought to be a ‘soup’ of elementary particles and antiparticles at this time.

The Quark Epoch

During this time, starting 10^-12 seconds after the big bang, the electroweak force was separated into the weak force and the electromagnetic force. Only then did physical laws become what they are today. By 10^-6 seconds, the start of the Hadron Epoch, temperatures had dropped to 10^11K, and gluons could bind quarks together.

The Hadron Epoch

In the beginning of this period, vast amounts of quarks and antiquarks had combined to form particles called Hadrons, hence its name. Some types of Hadron particle include baryons (protons and neutrons), antibaryons, and mesons. The antibaryons and mesons, however, quickly decayed or were annihilated after they formed. The protons and neutrons formed during this epoch were done so through  quark confinement, where ‘up’ quarks and ‘down’ quarks combine with gluons and make protons and neutrons. 

The Lepton Epoch

This period in the transformation of the universe starts one second after its formation, when the universe was around 10^10 Kelvin. During the Lepton Epoch, leptons (electrons, neutrinos, and their antimatter particles) were very numerous. The electrons had annihilated with positrons by the end of the epoch.

Big Bang Nucleosynthesis

During Big Bang Nucleosynthesis, collisions between protons and neutrons began forming helium-4 nuclei, and tiny amounts of other atomic nuclei, like helium-3, lithium, and deuterium. These reactions finished within twenty minutes, and by that time, 98% of the helium atoms today had formed.

The Photon Epoch

Throughout the Photon Epoch, which lasted 380,000 years, the electrons, protons, and helium nuclei were constantly interacting with photons, which made the universe foggy.

The Recombination Epoch - 380,000 years after the Big Bang

When the temperature had dropped to around 4000 Kelvin, the protons and atomic nuclei had begun to capture electrons, which formed the first atoms. During this era, the Universe became transparent because electrons had stopped scattering photons after being bound up in atoms, and matter and radiation therefore became ‘decoupled’. The photons were released to travel through the Universe as radiation. The first free photons can actually still be detected as the cosmic microwave background radiation, or CMBR.

THINGS STARTED FORMING

The Aftermath of the Big Bang

When the Universe was 400,000 years old, it was filled with photons of radiation streaming in all directions, and atoms of hydrogen and helium, neutrinos, and other dark matter. Astronomers try and look back into that time, and even though it was around 3,000 degrees celsius and filled with radiation, they see no light. This is because when the Universe expands, it stretches the wavelengths of radiation by 1,000x. We see the photons as cosmic microwave background radiation. Their wavelengths are now that of an object with a temperature of 3 Kelvin.

The First Stars

The first stars are thought to have formed roughly 180 million years after the Big Bang. They were all made of hydrogen and helium, because there weren’t really any other elements in the universe. Physicists think that nebulae that form stars would have condensed into larger clumps than those around today. The stars that formed these clumps would have been extremely hot and large, with masses between 100 and 1,000 times the mass of the sun. Although many of these stars only would have lasted a few million years before dying as supernovae, ultraviolet light from these stars may have actually triggered a key moment in the transformation of the Universe. Either the first stars, or radiation from quasars likely re-ionised hydrogen from a neutral gas to the ionised form seen today. 

Early Galaxies

Astronomers are still trying to determine exactly when in time the very first stars ignited, and what types of galactic structures this could have caused. They have recently used instruments like the Spitzer Space Telescope and the Very Large Telescope to perform infrared studies and hopefully find early galaxies. Amazingly, they found very faint galaxies with very high red-shifts that existed as little as 400 million years after the Big Bang! One of these is GN-Z11, which is the most distant galaxy known. 

Cosmic Chemical Enrichment

The first massive stars created and dispersed new chemical elements into space during the course of their lives and deaths. Elements like carbon, oxygen, silicon, and iron were all formed in the cores of these stars from nuclear fusion, and during the stars’ violent deaths, they formed elements like barium and lead. 

Stars smaller than the first megastars, second- and third- generational stars, formed later from the interstellar medium. They created some of the heavier elements, then returned them to the interstellar medium through stellar winds and supernovae explosions. 

Galactic mergers and the stripping of gas from galaxies led to even more mixing between the galaxies, and these processes even continue today.

This is really important, because without these new heavier elements, living organisms on rocky planets (like us) would not have formed.

THE UNIVERSE’S END

The Big Crunch

The ‘Big Crunch’ theory of the end of the Universe is currently regarded as the least probable of the 4 theories to actually happen, even though it’s the most exciting. According to this theory, all matter and energy will collapse into an infinitely hot, dense singularity, kind of like the Big Bang in reverse. If this were to happen, it would be tens of billions of years from now, so there’s no need to worry about the incredibly painful death this would bring.

The Big Rip

With this theory, the Universe would end with the strength of dark energy increasing so much that it would overcome all the fundamental forces and completely disintegrate the Universe. First, galaxies would be ripped apart, then even planetary systems like ours would be torn away from each other. We would have to say goodbye to any sunlight or warmth ever again and hello to a frozen death, but luckily this won’t happen until 20-30 billion years from now. Even if the theory is correct, we won’t be alive to experience it ourselves.

A Cold Death - The most probable theory

If the Universe were to end with a Cold Death, it would happen with galaxies eventually exhausting the gas that can form new stars, in about a trillion years, or 10^12 years. After this, in about 10^25 years or 10 trillion trillion years, most of the Universe’s matter will be in black holes and burnt-out white dwarfs that circle and fall into the supermassive black holes in the centres of galaxies. Then, in 10^32 years, protons will start to decay into photons, electrons, positrons, and neutrinos, and all matter that isn’t in black holes will fall apart. 10^67 years after that, black holes will start evaporating by emitting particles and radiation, and in about 10^100 years from now, even supermassive black holes can evaporate. The Universe will then be nothing more than a diffuse sea of photons and elemental particles.

Another version of The End which also leads to a Cold Death

In this theory, structures that are not bound by gravity will fly apart faster than the speed of light  if the effects of dark energy continue the way they are now. (Whilst no matter can travel through space at greater than the speed of light, space itself can extend this speed limit). This theory also gets to the same Cold Death as the previous one, it just took a slightly different approach.

[random2908]

hello what do you mean you don’t believe in Planck lengths? am not an expert but they seem handy

Reduced unit systems (sometimes more generously called "natural units," as if all units aren't made up) can be useful, but it's epistemicaly dangerous to read too much into them. I'm going to give some examples first and then come back to the Planck length.

The first reduced unit system you learn in school is Gaussian units. Or, at least, that's the first system I learned; it's been slowly going out of vogue as a teaching tool for the past 30 years or so as Purcell’s very weird and difficult textbook has fallen out of favor[1], and maybe no one still uses it for intro EM anymore. Gaussian units are basically cgs, except that the vacuum permitivity constant, magnetic susceptibility constant, and the units of charge are redefined so that the former two don't appear in Maxwell's equations; and the unit of charge is defined by other units rather than being a fundamental, irreducible unit.

The results are, on the one hand, Maxwell's equations are more elegant-looking, the speed of light's relation to electromagnetic fields appears more obviously embedded in the whole theory, and the units of capacitance are in cm. Specifically, the capacitance value that you calculate in units of cm is what the distance between the parallel plates would be if the capacitor were a perfect infinite capacitor with vacuum separation. There is admittedly some pedagogical use and maybe even profundity to a capacitor calculation in Gaussian units, that's lacking when you do the calculation in SI units and get your result in Farads, which have no relation to any intuitive physical meaning. On the other hand, as I said, in Gaussian units charge is defined by other units rather than being its own irreducible unit; as far as we currently understand Field Theory, that is a philosophically incorrect way to view charge. So in that respect, reading too much into Gaussian units can be very misleading. And, more prosaically, since SI units include vacuum permitivity in the basic equations about electric forces, it's much more obvious how to change the basic vacuum equations in SI so that they take into account the existence of materials than it is to do it in Gaussian units.

Let's take a second example of reduced units: geometrized units (used in general relativity). In geometrized units, the gravitational constant G and the speed of light c are defined in such a way that they equal 1 times the correct units for everything to end up relating to mass. This makes a lot of the math simpler. It also does elucidate some connections between different concepts in general relativity--specifically, in geometrized units, the Schwarzchild radius of a black hole (i.e. the radius of its event horizon) is 2m, where m is the mass of that black hole. Then again, if you express the radius of anything other than a black hole in geometrized units, you'll still get an answer in units of mass, but the answer you get will have basically nothing to do with the actual mass of the object, which is obfuscating at best. Trying to read into it would only mislead you.

There are numerous other examples of reduced units. There are units where the fine structure constant is 1, or 1/c. There are units where the (approximate) mass of a proton is 1 (actually 1/12 of the mass of a carbon atom is 1). There are units where the mass of an electron is 1. Some of these are just thought experiments, some have their practical uses to simplify the math in certain specific fields of study.

But here's the most important thing out of all of this. Even if there's profundity to Gaussian units giving you what size your capacitor would be if it were perfect, even if there's profundity to geometrized units relating the mass of your black hole to the radius of its event horizon--even if writing an equation in one set of units makes some insight more clear when it wouldn't have been obvious in another set of units--even so, you can calculate all these things, and show all these relationships in other unit systems. You can calculate the Schwarzchild radius of a black hole in SI. You can calculate the capacitance of any capacitor in SI, and you can also calculate the distance between infinite parallel plates of a certain capacitance. These values are entirely independent of their unit systems.

And here's the more important version of that statement. Any unit system will show you relations between things, some more than others, but at the end of the day units are arbitrarily set by people and reading too much into them is an epistemic dead-end. The Gaussian unit of distance (centimeter) is no less made up than the SI unit of distance (meter). The Gaussian unit of mass (gram) is no less made up than the SI unit of mass (kilogram). Etc. And most crucially, a unit system cannot give you unique insights, it can only show you relations that were more obscure from other viewpoints. Once again, every result you can calculate with one valid system of units, you can also calculate with any other--just some make the math easier.

Which brings us, finally, to Planck units. Planck units are yet another set of reduced units, this time with the gravitational constant G, the speed of light c, and the reduced Planck's constant hbar all set equal to 1, and all other units shuffled around to accommodate that. Planck was just playing around in a "what would happen if…" way when he did that--unlike geometrized units, Planck units were not invented for a purpose. But the unit distance you get in Planck units, when you convert back to SI, is very small: 1.6x10^-35 m. The unit time is also very small: 5.4x10^-44 s.

So people were like, hey, maybe this is the smallest things can get! Maybe this is the length scale at which space becomes quantized[2]. Which is utterly specious. Why. Why would it be. Who even said that it was--did any of your teachers in school tell you that or did you pick it up from some pop-sci article that repeated it as fact? It's literally an arbitrary number that someone came up with while playing around with units. There are plenty of other cases of useful unit systems nevertheless giving falsely profound values, a couple of which I mentioned above.

And then they go on to try to apply it to quantum gravity, a field of study which is, let's say, currently wildly speculative and internally contentious even among people who believe in it[3]. Which brings me to my next point: mass. Of course there's such a thing as a Planck mass, too. Do you know what it is? It's on Wikipedia, you don't even have to calculate it yourself, it's 2.2x10^-8 kg.

2.2x10^-8 kg--what even is that?? Surely it's not something related to quantum gravity! It's… let's see, it's 1/4 of my daily levothyroxine dosage (granted the pill itself is much bigger). It's 100 times more massive than a skin cell. On the sand-silt-clay scale, assuming they're all made of quartz, it's the mass of a smallish silt particle, bigger than clay, smaller than sand. It's meaningless! It's a nothing number, neither particularly big on a cosmic scale nor particularly small on a quantum scale. Quantum gravity is not affecting my skin cells significantly more than it's affecting me in my entirety; it's not affecting clay significantly more than it's affect sand.

And most importantly, the smoking gun, is the Planck length as the unit of the quantization of space the result you get in other units systems? No, because you don't get an answer to this question at all in other unit systems--not with our current level of knowledge. A unit system can rearrange things in such a way that when you look at it you see insights different than you saw with a different arrangement. It cannot give you new results out of whole cloth.

In other words, the Planck units, like all units, are entirely made up; ascribing meaning to them is misleading; and the discussion of the Planck lengths as the unit of quantization of space is most likely specious.

---

[1] I hated Purcell’s book as my first course in EM; I found it way too hard. The only thing I liked about it was that it taught relativistic magnetism as its FIRST explanation, which was a real sense-of-wonder moment for me in an otherwise overwhelming class. In retrospect, I appreciate the beauty of a book where if you're clever you can solve most of the homework problems in your head and if you aren't clever (me, mostly, my first time through, at least in part because I hadn't had any EM in high school) you can still solve them with multivariable calculus, so it works for different levels of students. (Unfortunately at my school, most students--myself included--took multivariable calculus at the same time as EM, so I couldn't solve the homework problems with multivariable calculus either until most of the way through the semester.)

[2] Personally, I think it's likely that there is a length scale at which space and time are quantized. I just don't see any reason it should be at a Planck length and time, specifically--or any other specific value, at least as of our current knowledge. Like, maybe it is, who knows, I guess, but the likelihood seems small. Anyway, not all physicists even do think space and time are quantized at all; even for myself I wouldn't consider it a "hard" belief so much as a guess. So for some physicists would consider the whole discussion specious in the first place, before you even get to considering the candidacy of specific lengths.

[3] In much the same way as my previous footnote, I think it's likely there exist undiscovered phenomena that we might consider to be quantum gravity. I again consider this a guess, rather than something I would bet money on.

ETA: This may be the first physics post I've ever written on here where I'm genuinely concerned someone's going to jump in and say "you were asleep when they taught [X] in school, but actually you're completely wrong about this." Like. I don't think that's likely to happen. And the vast majority of my physics posts have been outside of my specific expertise and I've never gotten that. (Although I do think I'm better versed in philosophy of science than the average physicists.) But I'm particularly out on a limb on this one. Anyway, I'm putting this here partly as an "in before [Y]" but also partly to point out that there are plenty of things that physicists are simply not in agreement on, and some things are actually closer to opinion than facts, even in physics.

[physicsofimportant]

2. Planck's time (tₚ).

At the heart of the computational dramaturgy concept lies the notion that the world, viewed as a Universal Turing machine, does not possess time as a separate essence from matter. Rather, the human perception of time is akin to a computational program, where each step corresponds to one Plank's time. This also affects the spatial coverage that can be achieved within a single "turn," lasting for a duration of a Plank's time and indivisible into smaller units.

In our proposition, we suggest that during this incredibly brief interval of 5.39 × 10^(-44) seconds, only one complete computational event takes place, which we refer to as dramaturgy.   Within this interval, there simply isn't enough time for more than one full computation or dramaturgical occurrence to unfold within a single atom of space. Therefore, we consider this rate of step changes in our universe's Turing machine to be fundamental.

Let's consider the magnitude of computational events occurring within our universe. The ratio of these monumental dice throws is an astonishing 1.846 × 10^43 throws per second! That’s how much Planck’s times fit in our regular second. This number is more comparable to the total number of atoms in the observed universe than to the span of a human lifetime.

To put it in perspective, one second is approximately equal to 1.846 × 10^43 Planck's times. In one year, there are approximately 5.8 × 10^50 Planck's times, and over the course of the universe's existence, which spans approximately 13.7 billion years, there have been approximately 8 × 10^60 Planck's times.

Within this unfathomable span of time, our reality has undergone around 8 × 10^60 computational steps, progressing from minimum possible entropy ever existed to the complexities of our present world during it’s natural process of increasing entropy. This encompasses everything from profound scientific discoveries to the light-hearted amusement of cat memes and various internet diversions. Surfers on the waves of reality. 

 8000000000000000000000000000000000000000000000000000000000000

On the other hand, this number is far beyond infinite and, upon reflection, it even appears surprisingly small. Nevertheless, it serves as a reminder that despite the vastness of the universe, each individual entity holds a finite number of chances to shape their own destiny and make an impact on the world.

And Average life of 70 year old person means that human entity was present for 4 × 10^52

clicks of our Mighty Turing Machine of the universe! And this is not just a number. It’s a minimum possible dramaturgical quantum steps sequence of the entity holding dramatic potential that can actually make choice and effect the system! Everyone who you know and you yourself have about 4000000000000000000000000000000000000000000000000000 chances to get your shit together and become a leader and a master of your life! Even if it sometimes feels you got none of that chances at all. 

For comparison, the estimated number of atoms in the observable universe ranges from 10^78 to 10^82. The observable universe is thought to be approximately 93 billion light-years in diameter. This means that you have plenty of chances to affect the dramaturgy of reality if you live long enough. You are part of a decision-making machine that has the potential to communicate at a rate that is more than half of the number of atoms in the observable universe. 

 The point is to emphasize the importance and "size" of a human being, which is truly outstanding.

It is fascinating to note that the average density of matter in the universe is about 5 atoms per cubic meter, whereas the average density of the Earth, considering its rock material, is approximately 10^22 atoms per cubic meter. 

In the vastness of space, an average seemingly empty cubic meter typically contains about 5 atoms with the potential to engage in the unfolding of dramaturgy. On the other hand, planet Earth, along with your own body, possesses an impressive density of approximately 10^22 atoms per cubic meter, ready to engage in all kinds of dramaturgies. Just imagine the immense possibilities and options you possess compared to the average observable universe!

 It truly is a miracle that within your lifetime, you have approximately 4 × 10^52 chances to act as you desire, and an abundance of 10^22 atoms per cubic meter to manipulate and play with in every moment. You are a god within this system.

If we were capable of perceiving each individual Planck's time, living our lives and experiencing the unfolding of the universe would be an eternity in itself. However, higher-dimensional entities that might exist beyond our three-dimensional + time world and conventional understanding of time reside within the realm of Planck's time. To them, it appears as a frequency or rhythm, much like the sound of a motorcycle engine. They can hear it and enjoy the ride. These entities possess the remarkable ability to perceive each small click of Planck's time, allowing them the luxury of taking as much "time" as they need to make personal decisions within each click. They interact with our world through various systems, such as corporations, marriage, Ronald Mc Donald, operating on a different level of consciousness, free from the constraints of our limited temporal perception.