The Planck Temperature: How hot can the Universe get?

The Planck Temperature – Absolute Hot: What is the hottest temperature possible.

Today I’m going to look at the Planck Temperature and it’s about to get very strange. Let’s find out more.

Planck temperature is what we think is the highest temperature possible. It is the temperature at which our understanding of the universe breaks.
In this video we’re going to try to imagine just how hot that is, and what the implications of this value are. In order to do this, we’re going to look at some other very hot things to compare.

Cup of tea image by TerriC

Desert image by photo-graphe

LHC tunnel image by Maximilien Brice at CERN, used under creative commons CC 4.0

LHC ATLAS calorimeter by Maximilien Brice at CERN, used under creative commons CC 4.0

[ksv]

Everyone's already mentioned how great your content is, so I just want to take a moment to talk about how great the commenters here are — after seeing almost every educational video on youtube bombarded with absurd top-voted comments about jokes, memes and other rubbish, it's so refreshing to see a comment section where I continue to learn from what people share. You guys (the creator and the viewers) are absolutely amazing. I especially loved David Pysnik and z beeblebrox's comments!

[DavidPysnik]

It’s amazing to consider that, in the “recent” history of the universe, both the hottest and coldest temperature to be found anywhere for a given time might have been right in the vicinity of earth and produced by humans.

[z-beeblebrox]

3:54 Also a fun consequence of the universe starting out extremely hot and cooling to its current very cold state, is if you go far enough back into the past, you MUST reach a point where the entire universe was room temperature. This was about 15 million years after the Big Bang. Stuck in deep space? Just snag yourself an oxygen mask and a t-shirt and you'll be fine! Don't even worry about getting thirsty, all the water in the universe is liquid right now!

[alecisla]

We need to help and promote channels like this, pure science with no clickbaits, just awesome content full of information. Keep up the good work and thank you!

[Lumen_Obscurum]

Interesting, so if you heat the fabric of reality up to the planck temperature it spontaneously forms black holes or to think another way, cavities are created in the fabric of spacetime. This would be akin to when liquids are almost boiling, so you could make the conjecture that if you heat anything to the planck temperature you've reached the boiling point of reality itself.

[billhillard]

As a physicist, I just need to correct one thing! The hottest temperature ever found on earth is that hot pizza cheese hitting the roof of your mouth. This can be read about in Planck's "Hot Pocket Theorem." I am sorry, I will go away now. 😁

[TheDavidPoole]

THEY FINALLY DID IT!
A non click-bait channel without sensationalism and hyperbole. All meat, no filler, and understandable.
Thanks for the great info, and staying realistic by acknowledging more "learned" people and asking for input. Can't help there, lol. Great video

[lorenwilson]

Fusing silicon into heavier elements releases less energy than fusing hydrogen into helium. Most of the increase in temperature in the star is due to the star shrinking in size as the fusion process continues. Basically, the star is converting potential energy of matter being farther from the center of the star into kinetic energy, which is expressed as hotter atoms. Initially, the proto-star's core is not hot enough to fuse anything until it contracts and heats. This heating is simply due to the atoms getting closer together and happens all over the earth, although not so dramatically. Once most of the hydrogen is converted to helium, the star contracts and the core warms up until it is hot enough to initiate fusion of helium. This continues until the star turns most of its matter into iron. Stars that are too small don't heat up enough as they contract and eventually stop short of forming either a neutron star or black hole (or more exotic paths of the very large stars). These stars become white, red, or brown dwarfs.

[MichaeltheORIGINAL]

Hold there, how is this channel so criminally underrated? That video was amazingly well done. Very interesting.

[phazei]

Would love to see a "what if" example if the magnitude of that heat. Like, if there were a sugar cube sized piece of matter at the planck temperature, would that be enough heat that it's dissipation would burn up a city? ocean? globe? Could help give a sense of magnitude.

[tf_d]

Adding a delay to the thunder after the lightning strike at 5:41 was such a nice detail! Your attention to detail is great :)

[davidjordan]

My big takeaway from this is that our personal notion of "normal" is, relatively speaking, just a whisker away from absolute zero. And yet, there are all sorts of interesting things happening. Like the famous three states of matter (plus I suppose plasma, which is the fourth), all of which don't come into play unless we're in this almost-zero condition. It seems highly unlikely to me that all the interesting stuff would be happening on one end of the spectrum. The video mentions some interesting things that start to happen at the high end as well. So are there similar states that manifest throughout the temperature range? Or is it just boring in the in the middle?

[philcourteney]

You deserve 10^15 times more subscribers! All killer no filler, clear and understandable, great visuals, and the audio quality is spot on! I’ve only just discovered this channel and I’m so happy!

[dxitydevil]

Great video, this was really interesting, ,, and even almost scary to think about. Like we can never comprehend these temperatures </3

[LearningCurveScience]

A few people have mentioned it, so I thought I'd pin a comment up here. Please be aware there are a couple of possible jump scares at roughly 5.40 and 12.40 (sorry about that). And again, a massive thank you for watching!!

[lars]

This is one very, very interesting concept to say the least. Great job explaining it all

[WackoMcGoose]

Planck Time: the smallest unit of time where anything can be said to meaningfully happen, the "frame rate" of the universe
Planck Distance: the smallest unit of distance where something can be said to have moved to a different position, the "resolution" of the universe
Planck Temperature: ...not a unit, but the top end of the temperature scale, as far from absolute zero as the laws of physics allow
...seems legit.

[Lightspectre]

Hi there. I am a physicist and I published my doctoral thesis on the Quark-Gluon Plasma created at the LHC at CERN. Great video, but you sort of lose the plot around 13:22 . Firstly, as you yourself point out, the concept of 'relativistic mass' is a contentious one within the community. Einstein's equations (and experimental evidence) shows that *momentum* increases non-linearly with greater and greater speed, p=ymv, where y is the relativistic gamma ( y = 1/root(1-v^2/c^2) ). But the rest mass (E=mc^2) remains the same. So you either have to say that there are multiple types of "mass" ('relativistic mass' and 'rest mass', M=ym)... which is kinda a weird idea if you think about it. Or you can just say that there are multiple 'types' of velocity (V=yv). Both idea work to explain observations, but the second idea is much more popular because the idea of 'relative' velocities is consistent with the rest of Eistein's theory of 'relativity' and the first idea is not.

Secondly, while it's true that the strength of gravity increases as you add kinetic energy to a system, it's a huge leap in logic to say that maybe gravity will become so strong that is creates mini black holes which somehow evaporate and cool the system. Rather, I would say that our current models simply don't predict what will happen if black body radiation becomes on the order of the plank length. We have absolutely zero experimental observations in that regime - it's all 100% speculation. Objects in this temperature regime don't 'break physics' anymore than Kepler's observations of the planets 'broke physics'. Instead, we just don't currently have a model that explains what might happen in this scenario. You kind of say that at the end, but only after you - pardon my harsh language here - wildy speculate about a fringe theory with no evidence. I think you could have just skipped to "I don't know".

And it's okay to say 'I don't know'. Admitting ignorance is the foundation of the scientific method.

[yannck]

Idk why but I tried calculating the Planck temperature using the constants and formula shown at 11:30. However when I did so, I got the wrong answer. So I looked it up and it appears that you wrote down the value of the Planck constant (h), while the formula seems to use the reduced Planck constant (ħ), which is equal to around 1.05457×10^-34, or h/2π. Using this value does give the temperature mentioned in the beginning of the video.

[khmer]

Wow! He explains everything in a way that's so easy to digest and understand but not so stupidly oversimplified that you lose the point. Congrats on that alone! Also, the video is really well put together, so amazing job on that as well. I'm definitely checking out your channel after I finish this video.