First I thought you made a typo and this video would be about why massless particles must travel at c. I had never heard about this GZK limit. Thanks for this new info!
First timer here. Really appreciate that the topic is not "dumbed down" like so many other sci-sites. Showing the math makes all the difference! Suscribed...thank you.
It's very rare that I come across a video talking about something I have literally never heard of before by any of the thousands of physics videos I've watched over the years. Excellent!
Legit question, if you’re watching physics videos for years then maybe it makes sense to go study physics at uni? These videos are nice, but they don’t really capture the picture of how a lot of things are derived
@@tgr5588 If I would study any subject where I watch hundreds of videos about for years, i would have like 8 majors. People sometimes just like to learn things. (or have ADHD like me)
@@tgr5588 Why do you suppose that watching thousands of physics videos implies no formation in physics? The GZK limit is not well known to physicists in general, it's a very niche phenomenon. I'm pretty sure most post-docs in physics don't know about it.
What a fun and interesting dip into relativistic particle physics! Great job making the video so accessible… we predict rapid channel growth heading your way!
Thank you for building up such a topic with a historic reference frame. It makes the topic so much better to understand and to enjoy. Also, switching between you talking and animations was well balanced, adding to the lecture. I'd like more of this!
Not only that, but those protons would "see" light going a 1c FASTER than them. Lots of people visualizing this think light might seem very slow for them. But they don't. And its one of the "craziest" things about our universe.
Ohhhh, subscribed! Walking through the math is incredibly useful. "There's a frame of reference where the CMB is stationary" is a concept I've never considered, thanks for blowing my mind like that
This is one of those things that is staring you right in the face the whole time and is so simple, but it just never dawned on you ( at least that's how it is in my own point of view 🤣). Very informative and simplistic video!
It isn't a limit like the speed of light. It just explaining why we don't detect any protons going faster than that. If a high-energy cosmic ray doesn't interact with a photon from the cosmic microwave background, it would continue traveling through space without losing energy through pair production. This could allow it to maintain its high energy and potentially travel long distances across the universe.
@@realityisenoughcould you please elaborate how you mean this. Because in my opinion his understanding is not wrong on a "fundamental" level. Yes there are inaccuracies but nothing I would describe fundamental.
Why don't you try accelerating while radiation of a temperature of about 8.8 x 10^13 K is slowing you down before you come here with your criticism, mister?
@@realityisenough They're really not. That cross sectional calculation gives you the average time it takes for an interaction with the CMB to happen. It in no way guarantees that it does happen anywhere near that time frame, or at all. Yes, for most particles, this will be fairly close, but some particles can just plain get lucky.
@@realityisenough I think you've got that the wrong way round. Even the video itself stated that protons would have no upper bound to their velocity if it weren't for CMB interactions.
The CMB shows us that we are moving relative to some frame, because we see a clear dipole, and also a quadrupole moment in the observed temperature. The postulate of relativity does not hold for our local, real universe because we are not in an absolute vacuum. If you try to travel close to "c" relative to your starting frame, the CMB will increase in energy to the point where it will eventually turn you into plasma.
@@samscott6880the CMB creates a preferred reference frame which relativity says does not exist. It’s not really a conflict, since the CMB is light acting within the universe, but it’s potentially useful nonetheless.
Good video though the number slightly wrong in the beginning, i.e incorrectly rounded, rather truncated, see it more accurate at 10:01 then there also 21 nines then ending in 866.
In a lot of Physics related videos, I have not found lots of people talk about Cosmic Background Radiation but you did. It is an important piece in the mystery of cosmos in my opinion.
I didn't understand most of this (I only have high school physics), but I do enjoy trying to understand this speed of light limitation. So far this is the best video to explain the why of this limit. I will be watching this again and again until I 'get it'. Thanks! Subcribed.
Hi, it is nice to hear you are interested in physics :) The fact that there is a fundamental speed limit (the speed of light) is just observed fact and nobody knows why the speed limit is exactly the number it is. It is just the way the nature is and we have no clue why. This video is talking about the fact that protons have even lower speed limit than the speed of light.
@@lukasrafajpps Indeed. But, it is also intuitive to accept that particles with mass cannot infinitesimally approach the speed of light, as it would practically equal the speed of light then, therefore occupying all of the available energy in the Universe. The explanation as to what that limit really determines, may then be quite revealing to a non-physicist.
It is encouraging to notice that people without a university or college background in natural sciences are interested in such topics at all. Please keep this attitude up and remain interested! I hope this enthusiasm will irradiate towards others and induce some spark of enthusiasm as well. There is so much noise in this present-day world that distracts our attention away from what is really defining our world and our knowledge, that videos like this are a relief in that sense.
Very interesting subject - and well presented! Still, you offered enough to get my mouth watery, but not enough to develop a satisfactory understanding. I'd like to hear a little more detail about the interaction between the proton and the microwave background.
I was thinking to write a short pdf script to every video with a bit more math so that viewers interested more into the topic could download and read but I didn't manage to find time yet.
That'd be awesome 😎 I get it though, that's another hour or two even if you speech to text the transcript and just insert your math addendums at the places indicated. At least if you're a format perfectionist like me anyway 😉
Thank you, this is an awesome video. From simple examples to real numbers in maths. 4:09 Aliens! (it's never aliens) 8:30 "photon on it's own..." proton, it happens. 10:44 Cool, I've never heard of that unit of measure!
Excellent presentation on this curious subject. One comment: 50 J is below the low end of bullet energies (~150 J) and much lower than standard ones (>1000 J). Not recommending a 50 J bullet to anyone, but, still. Cheers!
This is the first time in a long time I learned something new about physics. I haven't been seeking out more knowledge how I used to and this makes me nostalgic.
This is a truly great video - one the best physics videos ever. It raises the question: What else might the CMB affect? How might it affect neutrino flavour switching? Does genuinely new physics emerge at the interface between c and the CMB reference frame?
Very nice video, both a lot of detail and easy explanations. Relativity declares that no rest frame has special rules of physics. But it's been mis-taught as "there is no universal rest frame," when for many purposes the CMB fits the bill. This also answers my anxiety-inducing thought experiment of "what's stopping near-light speed objects from coming from deep space and just absolutely annihilating us?" This at least puts a rough upper bound to what's possible.
For best results in building an electroscope, use gold leaf for the hanging flaps. Gold leaf is beaten to an extreme thinness, and hence weighs less, and hence moves more for a given charge, and hence its displacement is more visible. Ordinary aluminum foil can be used instead of gold leaf, but the flaps must be very narrow to see anything.
I enjoyed this video very much. I found you to be very well spoken and engaging. I hope you have great success with your channel and your Ph.D. studies. Thank you. InscrutableJohn
Very interesting. Thank you for giving me a new obsession. Now I need to watch this every night for months. And the dreams too are going to be great. 😊😊😊
In your final calculation, where you find 'days' for the interaction, you appear to calculate gamma using (v/c) rather than (v/c)^2. Using the correct calculation should yield an interaction in 'moments' rather than 'days' (in the proton's timeframe). Otherwise, good perspective!
Did a quick research on how far is 25.7M ly, and aparently there's plenty of galaxies within that range, Andromeda is about 10 times closer than that. So it's possible that those OMG particles were formed quite close to us.
Thankyou for this vid... before watching I had naively assumed that this upper speed limit might be due to the increase in relativistic mass pushing the proton mass up so high it would become a blackhole but now I see that I'm probably orders of magnitude off when this would (could?) happen. Thanks again.
The time dilation equation of STR does not include the equation for length (x=ct) since the equation to be solved for t' is: (ct')^2 = (ct)^2 + (vt')^2 which cannot be generated from ct' = ct + vt' in first order. Speed is irrelevant. Einstein is wrong. The equation misleading "time dilation" equation suggests the force relation in first order (from a second order equation) f' = ct'= ct(G), but Beta = v/c = mv/mc (valid for any m). The correct analysis is that space (x = vt) is not included in the equation to be solved for the "time dilation" equation. (ct')^2 = (ct)^2 + (vt')^2 (solve it for t' for yourselve(s) to understand) and note that this equation cannot be generated from the "space" equation for length in first order (ct') = (ct) + (vt') (draw it on a piece of paper). Hint: If space doesn't exist, the twins don't go anywhere; one of them (the imaginary one) just gets fat in his/her imagination (t'). Which is why Hawking hints that time must be imaginary, but never says why. "Yesterday upon the stair I saw a man who wasn't there He wasn't there again today Oh, how I with he'd go away" - Ogden Nash See my post at "From MM Experiment to STR" at physicsdiscussionforum "dot" org That is, Fermat's Last Theorem is valid for the case n=2 for all positive real numbers c^2 a^2 + b^2 since in second order (I repeat, sigh. ad infinitum, ad nauseam) c= a + b c^2 = [a^2 + b^2] + [2ab] (Binomial Expansion, proved by Newton) [a^2 + b^2] (why) figure it out and you will be enlightened....😎
"Fermat's Last Theorem is valid for the case n=2 for all positive real numbers" What are you smoking? Fermat's Last Theorem is for positive INTEGERS. Consider visiting psychiatrist. You make trivial logic errors. This is not normal.
Yep, time to accept that reaching let alone breaking the light-speed barrier is about as likely as Santa Claus turning out to be real. It just ain't gonna happen. The very notion defies logic itself. 😢 I guess that's the price we must pay for the privilege of living in a predictable universe where effects always follow causes.
This energy is some orders of magnitude bigger to turn something of the radius of a proton into a black hole. But this would be a fast moving black hole and this would mean it has very different gravitational effects on its surroundings than a stationary or not relativistic fast black hole. So no one really knows exactly how this would work out.
Great video as always! I was very surprised that the limit had to do with the CMBR interaction. My first guess was that there would be a speed limit for protons when their total energy was large enough to create a black hole. As far as the limit you present, I don't think it's universal. In principle, couldn't one build a large Faraday shield which would prevent the proton from interacting with the CMBR? I'm guessing the calculation of the kinetic energy of a proton needed to collapse into a black hole is not too difficult.
For people that can't contextualize how insane 50 J of energy from a single proton really is, here is a little example: A single proton is a hydrogen nuclei. At STP, one mole of hydrogen gas is ~87% of a cubic foot. For my purposes, you could hold the container in your hands easily. There are Avogadro's number hydrogen atoms (pretending their just nuclei is sufficient) ~ 6 *10^23 Thus if this mole of gas was accelerated to the same energy as the single proton, there would be 30*10^24 = 3*10^25 Joules A quick google search shows (approximately) 4.2 *10^9 J = 1 ton of TNT, So, ~3/4 or: 0.75*10^(25-9) = 0.75*10^16 = 7.5*10^15 tons of TNT That's 7.5 MILLION BILLION TONS OF TNT. A billion megaton nukes, a million gigaton nukes, etc. I believe that is more energy than all of human activity in our entire history has created, or something close to it. Absolutely insane.
It occurred to me recently that such highly energetic protons might be produced in the evaporation of primordial black holes. The Hawking radiation generated by a black hole becomes increasingly energetic as it becomes smaller. A black hole on the verge of vanishing completely should emit particles close to the order of magnitude of the Planck energy, which is well beyond the GZK limit. At least, if the math in regards to such evaporating black holes is correct.
Thanks, I am enjoying your content :) > Some part of me always questions if a photon is truly traveling at the "limit", or if the photon is just the most obvious observable for us and other unseen "stuff" can travel faster. (Keeping in mind, when we start talking about n decimal degrees of precision, that the speed of a photon is just a low precession estimate to begin with)
I wanted to say light years and I noticed this mistake when editing but since in this context it is kinda interchangeable I didn't bother to redo the whole thing just because of it.
*A* standard frame of reference, not *the* standard, since that doesn't exist under special relativity. But the CMB is nice and universal, so it's pretty convenient.
It is a unit used in particle physics and its definition is literaly 10^-28 m^2. If you will you can think about it as a thickness of the particle, the more thick the more likely the interaction is gonna happen.
Keep it up, rooting for you. On a critical note tho, this script felt like it was run through ChatGPT, choppy, random subject jumps, awkward transitions and broken pace. Hope you find your own flow and faze out trying to imitate a style, without even the self confidence of pulling it off.
It is somewhat counter intuitive to consider that going very fast could mean coming to rest for anything. But that's how it is for everything that has a constant speed.
Ein Kunststoffeimer gefüllt mit Einer Atomsorte oder mehreren wie Wasser, mit der einen Atomsorte die ausgegast werden soll. 2 Kupferstäbe sind in den Eimer zu 2 mal Negativen Strom und und Kupferkabel je 1. Dann kommen die Regler von Unten gesehen wo die 2 Kupferkabel enden. Die 2 Regler sind zusammen unterer Regler nach Rechts und Oberer Regler nach links. Es entsteht wieder 1 Kupferkabel mit Negativen Strom. Man sieht keine Blasen und es Gast trotzdem aus. Wasserstoff 1,008 mm. Stickstoff 7,? mm. Es handelt sich um die Masse.
also as the universe expands this limit increases, i wonder what is the formula f(% of C ) that returns the time we need to wait to be able to get a proton to that speed, and if a proton can go, a space ship can as well? or other stuff breacks before?
I've thought about the issue of blue-shifted CMB as a hazard to moving through space near light speed. So, this is where protons start to interact. I would guess atoms will disintegrate at a lower speed than this GZK limit. On the bright side, at some speed before your ship disintegrates, you'd have plenty of light to see by!
not to mention that after certain speed the CMB would become a ionizating radiation but I would have to calculate what doses of radiation would a man get at certain velocity :)
The random, abrupt digital zooming is a distraction. I suppose it probably serves a purpose or maybe it is like podcaster's Super Giant earphones that are obligatory. It's just what is done to seem professional or something.
6:03 what exactly are these "knee" and "ankle"? When my mom blames rheumatoid arthritis pain on upcoming rain, can I joke that it's actually because of high energy particle events from the cosmic rays, stimulating her knee joints? 😀 P.S. It could be actually an interesting topic to think about how much of a human-particle-detectors we actually are! We definitely feel things with out eyes and skin, one could see some fancy flash of light after putting head in particle accelerator (like Anatoli Petrovich Bugorski), but what about more subtle electromagnetic radiation waves?
10:51 "The average distance a proton travels per one interaction is ~25.7 million years"? Was 'distance' supposed to be duration? A few sentences earlier it does specifically state the question 'how long' it takes, but then it turns over to 'distance' at the end and all calculations are in metric distances/surface areas, so it might also be that you meant 'Light years' instead of 'years'. (The on-screen answer also says lightyears) I'm not 100% confident if "years" is wrong here, it may be an interchangeable term (even if one-way) in some specific situations such as this one...
Distance and time are interchangeable. 25.7 million years is a pretty specific distance in terms of light speed. So in this case, a half life in time also corresponds to a half-life in distance.
distance and duration are the same thing in particle physics, since hbar = c = 1. That means it's also inverse energy (hbar x c = 197 MeV fm). That also means energy is frequency is mass (at rest), momentum is inverse distance...and if light: energy is momentum, frequency is wavenumber, and for some ppl k_B = 1, so energy is temperature (e.g., if some says "I'm a physicist!" and you say, "what's room temp in eV?", they either say 1/40, or they're a liar. Newtons G=1 means they're black-hole theorists. Regarding hbar x c, all nuclear physicists know that above number, while high energy experimentalist might say 0.2 GeV fm, and theorist would say "1". An atomic/quantum optics physicist should say 0.2 eV nm, but probably not since they work in the inverse cm. IR ppl use that too, and microns. Below that, passive microwave ppl prefer GHz, and radar ppl dip into MHz. I skipped the THz and < kHz crowd since I've never worked with them. edit: I skipped Dr Becky and the observational ppl, for whom red-shift, Z, is distance...but I can't forgive anyone who uses parsecs, which is no less geocentric, and more cultural tied to humans, than light-years.
Hi, yes I meant to say light years and I noticed the mistake when editing but since the protons are traveling really close to the speed of light then the proton travels basically 25.7M ly in 25.7M years so I didn't consider it to be a significant mistake to redo the whole part or distort the video in any way trying to correct the mistake.
I have heard somewhere that at close to light speed all the light is blue shifted to gama rays. Also will that proton not also hit photons from other light sources, that have more energy to start with?
So the most remarkable thing I learned is that if you travel near the speed of light, then relativity makes it so that the journey doesn't take as long from your perspective as it does for the people you left behind. You could travel the stars in just a few days... at least, so you'd experience, when actually millions of years have passed.
I have no understanding of physics but the subject fascinates me. The proton has a mass so it should be subjected to the laws of special relativity. I thought these laws predict that if - as particle with mass - you travel at speeds closer and closer to c your mass will become larger and larger and you will also start to deform in some specific way depending on the direction you're travling in. At c your mass would reach infinity. Is this correct? Or are there other laws/rules playing a role in this type of process?
Yes, though it's important to point out, that this special deformation, time dilation and increase in mass is relative. From the perspective of the moving object, it is the rest of universe that gets time-dilated, deformed and heavier. Mass is the measure of inertia - the resistance to being accelerated by force. If you have two objects, apply the same force to both of them, and the second accelerates half as quickly, that means the second object has double the mass of the first one. When we say that "object gets heavier the closer to c is moving" what we mean is that the same force accelerates the object less and less, the closer to c it is moving. You can still impart arbitrary amount of kinetic energy to an object. It just that, the closer to c you get, the less of that energy goes into making the object move faster, and more of it goes into making the object harder to accelerate (and decelerate).
I don't get it. Judging by what you say, this limit is purely probabilistic, and protons can't exeed it "on average". But there is still a chance that the proton won't hit any of the CMB photons in time and will exeed the limit. So the limit isn't really there. Am I missing something?
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First I thought you made a typo and this video would be about why massless particles must travel at c. I had never heard about this GZK limit. Thanks for this new info!
"Why can't protons travel faster than this speed?"
"You... you meant photons, right?"
"DID I STUTTER?"
@@General12th There is no such thing as a photon - Ken Wheeler
@@johnnym6700 oh god, the king of word salad
same here! had no idea there exist other universal speed limits below c
@@iLLadelph267 it's not really universal, though. It's specific to protons and a particular reference frame.
First timer here. Really appreciate that the topic is not "dumbed down" like so many other sci-sites. Showing the math makes all the difference! Suscribed...thank you.
Seconded
@@Hans-ChristianSchwartz Thirded!
It's very rare that I come across a video talking about something I have literally never heard of before by any of the thousands of physics videos I've watched over the years. Excellent!
Same.
Legit question, if you’re watching physics videos for years then maybe it makes sense to go study physics at uni? These videos are nice, but they don’t really capture the picture of how a lot of things are derived
@@tgr5588 If I would study any subject where I watch hundreds of videos about for years, i would have like 8 majors. People sometimes just like to learn things. (or have ADHD like me)
@@tgr5588 Why do you suppose that watching thousands of physics videos implies no formation in physics? The GZK limit is not well known to physicists in general, it's a very niche phenomenon. I'm pretty sure most post-docs in physics don't know about it.
Why does this not have 1M views yet.
What a fun and interesting dip into relativistic particle physics! Great job making the video so accessible… we predict rapid channel growth heading your way!
Hi, thank you very much for such words I hope you're right :) I wish you all the best on your RUclips yourney guys :)
Thank you for building up such a topic with a historic reference frame. It makes the topic so much better to understand and to enjoy. Also, switching between you talking and animations was well balanced, adding to the lecture. I'd like more of this!
I'll petiton my local council to raise the speed limit.
You can thank me now.
I'll sign but I think we'll need some good good luck 😅
thank you
Imagine being a proton traveling at 0.99..9998c and watching photons travelling past you at c :)
I want to but i can't because I'm using all my concentration to maintain my speed of 0.999c (yeah ONLY 3 9s. I'm 1 of the "slow" kids)
😁😁😁
The Naughty frames of reference.
Not only that, but those protons would "see" light going a 1c FASTER than them. Lots of people visualizing this think light might seem very slow for them. But they don't. And its one of the "craziest" things about our universe.
It’s still weird that even from the ultra fast flying proton frame light would move with c.
I have studied this effect in the uni a few years ago but totally forgot about it. Thank you for refreshing my memory hahaha. Nice video :)
New sub here. I love the pace, gives me enough time to actually understand what's being said before you move on.
Ohhhh, subscribed! Walking through the math is incredibly useful. "There's a frame of reference where the CMB is stationary" is a concept I've never considered, thanks for blowing my mind like that
The mis-teaching of relativity has obscured that fact, sadly. A related concept is the "comoving coordinates".
This is one of those things that is staring you right in the face the whole time and is so simple, but it just never dawned on you ( at least that's how it is in my own point of view 🤣). Very informative and simplistic video!
My first idea was "it'll decay into multiple particles". It seems like my toughts were not that wrong, but I also learned quite a few new things.
I love the accent! Rodiation! And Aye-ons! Just subscribed!
It isn't a limit like the speed of light. It just explaining why we don't detect any protons going faster than that. If a high-energy cosmic ray doesn't interact with a photon from the cosmic microwave background, it would continue traveling through space without losing energy through pair production. This could allow it to maintain its high energy and potentially travel long distances across the universe.
You're misunderstanding everything on a very fundamental level
@@realityisenoughcould you please elaborate how you mean this. Because in my opinion his understanding is not wrong on a "fundamental" level. Yes there are inaccuracies but nothing I would describe fundamental.
Why don't you try accelerating while radiation of a temperature of about 8.8 x 10^13 K is slowing you down before you come here with your criticism, mister?
@@realityisenough They're really not. That cross sectional calculation gives you the average time it takes for an interaction with the CMB to happen. It in no way guarantees that it does happen anywhere near that time frame, or at all. Yes, for most particles, this will be fairly close, but some particles can just plain get lucky.
@@realityisenough I think you've got that the wrong way round. Even the video itself stated that protons would have no upper bound to their velocity if it weren't for CMB interactions.
Great video, everything was well-explained with just the right amount of detail. Subscribed.
Thanks for the sub!
The CMB shows us that we are moving relative to some frame, because we see a clear dipole, and also a quadrupole moment in the observed temperature. The postulate of relativity does not hold for our local, real universe because we are not in an absolute vacuum. If you try to travel close to "c" relative to your starting frame, the CMB will increase in energy to the point where it will eventually turn you into plasma.
true :) CMB slightly breaks the principle of relativity.
@@lukasrafajpps How? The CMB is light.
@@samscott6880
I think it would blue shift into the X-ray energy and higher. Light can carry tremendous amounts of momentum.
This needs to be incorporated into science fiction novels.
@@samscott6880the CMB creates a preferred reference frame which relativity says does not exist.
It’s not really a conflict, since the CMB is light acting within the universe, but it’s potentially useful nonetheless.
That was very interesting. I'd never heard of Δ resonances before. Thank you.
I've not heard this explanation yet. Thanks! very interesting.
Yes, it's because of the new Welsh speed limit.
What a fascinating combination of effects.
I don't know what's more entertaining, the content or his accent. I like how he pronounces stuff.
:D there are divided opinions on my accent so thank you :)
@lukasrafajpps it is very strong, the accent, but that is your appeal, to me.
@@lukasrafajpps whatever it’s worth, you’re completely understandable, and by the end of 2-3 videos I don’t notice it at all. Maybe that’s just me.
Good video though the number slightly wrong in the beginning, i.e incorrectly rounded, rather truncated, see it more accurate at 10:01 then there also 21 nines then ending in 866.
In a lot of Physics related videos, I have not found lots of people talk about Cosmic Background Radiation but you did. It is an important piece in the mystery of cosmos in my opinion.
I didn't understand most of this (I only have high school physics), but I do enjoy trying to understand this speed of light limitation. So far this is the best video to explain the why of this limit. I will be watching this again and again until I 'get it'. Thanks! Subcribed.
Hi, it is nice to hear you are interested in physics :) The fact that there is a fundamental speed limit (the speed of light) is just observed fact and nobody knows why the speed limit is exactly the number it is. It is just the way the nature is and we have no clue why. This video is talking about the fact that protons have even lower speed limit than the speed of light.
@@lukasrafajpps Indeed. But, it is also intuitive to accept that particles with mass cannot infinitesimally approach the speed of light, as it would practically equal the speed of light then, therefore occupying all of the available energy in the Universe. The explanation as to what that limit really determines, may then be quite revealing to a non-physicist.
It is encouraging to notice that people without a university or college background in natural sciences are interested in such topics at all. Please keep this attitude up and remain interested! I hope this enthusiasm will irradiate towards others and induce some spark of enthusiasm as well. There is so much noise in this present-day world that distracts our attention away from what is really defining our world and our knowledge, that videos like this are a relief in that sense.
12:15 relativity is crazy Mr. Proton is going of for the weekend trip and Mrs. Proton staying at home has to wait 25 million years for him :(
Real world Hoshi no Koe.
Very interesting subject - and well presented! Still, you offered enough to get my mouth watery, but not enough to develop a satisfactory understanding. I'd like to hear a little more detail about the interaction between the proton and the microwave background.
I was thinking to write a short pdf script to every video with a bit more math so that viewers interested more into the topic could download and read but I didn't manage to find time yet.
That'd be awesome 😎 I get it though, that's another hour or two even if you speech to text the transcript and just insert your math addendums at the places indicated. At least if you're a format perfectionist like me anyway 😉
So all we need to see if a proton can hit the broad side of .1 millibarn
Excellent content! Please keep it up.
A very interesting effect, and a surprisingly simple one. Thanks for the video, I actually learned something new today.
Excellent, and good to see some numbers around interactions with a hotter CMB in the direction of travel for very fast particles. Thanks!
Wonderful vid, excellent visualizations, you rock!!
Will this number change as the CMB cools? What you're saying seems to imply this. Or am I misunderstanding?
Literally my first thought, so I popped into the comments. I haven’t seen it discussed anywhere here.
Homework for you: pause at 10:03 and think about what would happen to small beta, if you only lowered the value of the cmb radiation in the formula.
Thank you, this is an awesome video. From simple examples to real numbers in maths.
4:09 Aliens! (it's never aliens) 8:30 "photon on it's own..." proton, it happens. 10:44 Cool, I've never heard of that unit of measure!
Excellent presentation on this curious subject. One comment: 50 J is below the low end of bullet energies (~150 J) and much lower than standard ones (>1000 J). Not recommending a 50 J bullet to anyone, but, still. Cheers!
It's in the airgun range. In many countries you need a licence for air guns over 7 Joules.
It's in the .22LR energy range.
@@praveenb9048 -countries- *tyrannies
@@DrDeuteron soo.. you find it tyrannical, when the police has the monopoly for weapons, causing much less gun violence in that country?
example: Japan.
This is the first time in a long time I learned something new about physics. I haven't been seeking out more knowledge how I used to and this makes me nostalgic.
This is a truly great video - one the best physics videos ever. It raises the question: What else might the CMB affect? How might it affect neutrino flavour switching? Does genuinely new physics emerge at the interface between c and the CMB reference frame?
Cool. Thanks for sharing.
From one physicist to another, this was a great video!
Fascinating. I don't recall learning any of this story during my physics degree in the mid 1990s.
Very nice video, both a lot of detail and easy explanations.
Relativity declares that no rest frame has special rules of physics. But it's been mis-taught as "there is no universal rest frame," when for many purposes the CMB fits the bill.
This also answers my anxiety-inducing thought experiment of "what's stopping near-light speed objects from coming from deep space and just absolutely annihilating us?" This at least puts a rough upper bound to what's possible.
For a foreigner your English is really good. Understood every word.
it's mid
thanks :)
For best results in building an electroscope, use gold leaf for the hanging flaps. Gold leaf is beaten to an extreme thinness, and hence weighs less, and hence moves more for a given charge, and hence its displacement is more visible. Ordinary aluminum foil can be used instead of gold leaf, but the flaps must be very narrow to see anything.
I enjoyed this video very much. I found you to be very well spoken and engaging. I hope you have great success with your channel and your Ph.D. studies. Thank you.
InscrutableJohn
Thanks :)
Very interesting. Thank you for giving me a new obsession. Now I need to watch this every night for months. And the dreams too are going to be great.
😊😊😊
So then... I assume electrons have to be even slower then?
english isnt my native launguage, but your explenations are so great that I can understand it with my avarage level on english ;D
In your final calculation, where you find 'days' for the interaction, you appear to calculate gamma using (v/c) rather than (v/c)^2. Using the correct calculation should yield an interaction in 'moments' rather than 'days' (in the proton's timeframe).
Otherwise, good perspective!
Did a quick research on how far is 25.7M ly, and aparently there's plenty of galaxies within that range, Andromeda is about 10 times closer than that. So it's possible that those OMG particles were formed quite close to us.
The mystery is how something nearby could produce protons at such high energies without also being very easy to find by other means.
Thankyou for this vid... before watching I had naively assumed that this upper speed limit might be due to the increase in relativistic mass pushing the proton mass up so high it would become a blackhole but now I see that I'm probably orders of magnitude off when this would (could?) happen. Thanks again.
"Incorrect measurement" - top choice energy provider!
So interesting, thank you.
So it's relatively simple to shield from the CMB, is this limit more just a practical effect?
The time dilation equation of STR does not include the equation for length (x=ct) since the equation to be solved for t' is:
(ct')^2 = (ct)^2 + (vt')^2 which cannot be generated from ct' = ct + vt' in first order.
Speed is irrelevant. Einstein is wrong. The equation misleading "time dilation" equation suggests the force relation in first order (from a second order equation) f' = ct'= ct(G), but Beta = v/c = mv/mc (valid for any m).
The correct analysis is that space (x = vt) is not included in the equation to be solved for the "time dilation" equation.
(ct')^2 = (ct)^2 + (vt')^2 (solve it for t' for yourselve(s) to understand) and note that this equation cannot be generated from the "space" equation for length in first order (ct') = (ct) + (vt') (draw it on a piece of paper).
Hint: If space doesn't exist, the twins don't go anywhere; one of them (the imaginary one) just gets fat in his/her imagination (t'). Which is why Hawking hints that time must be imaginary, but never says why.
"Yesterday upon the stair
I saw a man who wasn't there
He wasn't there again today
Oh, how I with he'd go away" - Ogden Nash
See my post at "From MM Experiment to STR" at physicsdiscussionforum "dot" org
That is, Fermat's Last Theorem is valid for the case n=2 for all positive real numbers
c^2 a^2 + b^2
since in second order (I repeat, sigh. ad infinitum, ad nauseam)
c= a + b
c^2 = [a^2 + b^2] + [2ab] (Binomial Expansion, proved by Newton)
[a^2 + b^2] (why) figure it out and you will be enlightened....😎
"Fermat's Last Theorem is valid for the case n=2 for all positive real numbers"
What are you smoking? Fermat's Last Theorem is for positive INTEGERS. Consider visiting psychiatrist. You make trivial logic errors. This is not normal.
This is a heck of an interesting video! 👍
Greatly enjoy your content
At 10:01 you used c for value of beta which is not required as it is just a dimensionless ratio.
luckily c=1.
Yes true, sometimes I lose focus on these things. Thanks for correcting.
Amazing video, amazing explanation, amazing storytelling (and amazing accent hahaha).
+1 sub
thank you :)
Particle physics on youtube? I hit the subscription button at (near) the speed of light!
Man, it gets worse everyyear. We used to be able to at least hope we will reach lightspeed someday. And now this. Seems we can't even do that.
Yep, time to accept that reaching let alone breaking the light-speed barrier is about as likely as Santa Claus turning out to be real. It just ain't gonna happen. The very notion defies logic itself. 😢 I guess that's the price we must pay for the privilege of living in a predictable universe where effects always follow causes.
Thank you for this new video ❤
Excellent. Never heard of this before, but you explained it so well, even my average brain got a decent understanding.
Thanks for the kind words and the support. Much appreciated :)
I thought for sure this was going to be something like "beyond this speed, it has so much energy that it turns into a blackhole".
This energy is some orders of magnitude bigger to turn something of the radius of a proton into a black hole. But this would be a fast moving black hole and this would mean it has very different gravitational effects on its surroundings than a stationary or not relativistic fast black hole. So no one really knows exactly how this would work out.
Bit odd to show the email addresses of supporters ( @12:39 ) but OK
Great video as always! I was very surprised that the limit had to do with the CMBR interaction. My first guess was that there would be a speed limit for protons when their total energy was large enough to create a black hole. As far as the limit you present, I don't think it's universal. In principle, couldn't one build a large Faraday shield which would prevent the proton from interacting with the CMBR? I'm guessing the calculation of the kinetic energy of a proton needed to collapse into a black hole is not too difficult.
“OMG particle” how cool is that!
For people that can't contextualize how insane 50 J of energy from a single proton really is, here is a little example:
A single proton is a hydrogen nuclei. At STP, one mole of hydrogen gas is ~87% of a cubic foot. For my purposes, you could hold the container in your hands easily.
There are Avogadro's number hydrogen atoms (pretending their just nuclei is sufficient) ~ 6 *10^23
Thus if this mole of gas was accelerated to the same energy as the single proton, there would be 30*10^24 = 3*10^25 Joules
A quick google search shows (approximately) 4.2 *10^9 J = 1 ton of TNT,
So, ~3/4 or: 0.75*10^(25-9) = 0.75*10^16 = 7.5*10^15 tons of TNT
That's 7.5 MILLION BILLION TONS OF TNT. A billion megaton nukes, a million gigaton nukes, etc. I believe that is more energy than all of human activity in our entire history has created, or something close to it. Absolutely insane.
Thanks, man. That was interesting.
Does this radiation grow weaker over time since universe is expanding, thus allowing protons to go faster in the future?
great video thanks!
Continue.... Your channel is very good... Soon you will be famous U. tuber
It occurred to me recently that such highly energetic protons might be produced in the evaporation of primordial black holes. The Hawking radiation generated by a black hole becomes increasingly energetic as it becomes smaller. A black hole on the verge of vanishing completely should emit particles close to the order of magnitude of the Planck energy, which is well beyond the GZK limit. At least, if the math in regards to such evaporating black holes is correct.
Thanks, I am enjoying your content :)
>
Some part of me always questions if a photon is truly traveling at the "limit", or if the photon is just the most obvious observable for us and other unseen "stuff" can travel faster. (Keeping in mind, when we start talking about n decimal degrees of precision, that the speed of a photon is just a low precession estimate to begin with)
Thanks!
I thank you for the support :)
Great explanation of a very esoteric topic 👍
Exellent work!
Interesting... "Tall poppies" protons got energetically cut down in size, more or less spontaneouusly. Thanks for that bit!
11:01 it's written "ly" so light years, a distance, but you say "years". Was this an intentional équivalence?
Thank you for the great content!!
I wanted to say light years and I noticed this mistake when editing but since in this context it is kinda interchangeable I didn't bother to redo the whole thing just because of it.
Thanks for sharing.
New concept for me. The CMB sets a standard frame of reference. That changes a lot.
Anything can be a standard reference frame, a particular flight from NY to London for example, is just that the CMB makes for a very convenient frame.
*A* standard frame of reference, not *the* standard, since that doesn't exist under special relativity. But the CMB is nice and universal, so it's pretty convenient.
This blew my mind.
Great video, but please explain a "barn"? Maybe I misunderstood the word.
It is a unit used in particle physics and its definition is literaly 10^-28 m^2. If you will you can think about it as a thickness of the particle, the more thick the more likely the interaction is gonna happen.
Query: if a proton is moving at the GZK limit, and you add energy, wouldn't the resulting combination of mass/energy result in a black hole?
Keep it up, rooting for you.
On a critical note tho, this script felt like it was run through ChatGPT, choppy, random subject jumps, awkward transitions and broken pace.
Hope you find your own flow and faze out trying to imitate a style, without even the self confidence of pulling it off.
You mentioned heavier nuclei. Is there some reason they don't think it was, say, iron or bigger? If it was anti-matter would that change the readings?
Heavy nuclei would have a lower speed limit, due to photodisintegration from blue shifted photons.
It is somewhat counter intuitive to consider that going very fast could mean coming to rest for anything.
But that's how it is for everything that has a constant speed.
To put it simply using a very rudemtary metaphor , the intrinsic lag of the proton is barriered by the intrinsic frame rate of open space .
Ein Kunststoffeimer gefüllt mit Einer Atomsorte oder mehreren wie Wasser, mit der einen Atomsorte die ausgegast werden soll.
2 Kupferstäbe sind in den Eimer zu 2 mal Negativen Strom und und Kupferkabel je 1. Dann kommen die Regler von Unten gesehen wo die 2 Kupferkabel enden.
Die 2 Regler sind zusammen unterer Regler nach Rechts und Oberer Regler nach links.
Es entsteht wieder 1 Kupferkabel mit Negativen Strom.
Man sieht keine Blasen und es Gast trotzdem aus.
Wasserstoff 1,008 mm. Stickstoff 7,? mm. Es handelt sich um die Masse.
also as the universe expands this limit increases, i wonder what is the formula f(% of C ) that returns the time we need to wait to be able to get a proton to that speed, and if a proton can go, a space ship can as well? or other stuff breacks before?
I've thought about the issue of blue-shifted CMB as a hazard to moving through space near light speed. So, this is where protons start to interact. I would guess atoms will disintegrate at a lower speed than this GZK limit.
On the bright side, at some speed before your ship disintegrates, you'd have plenty of light to see by!
not to mention that after certain speed the CMB would become a ionizating radiation but I would have to calculate what doses of radiation would a man get at certain velocity :)
The random, abrupt digital zooming is a distraction. I suppose it probably serves a purpose or maybe it is like podcaster's Super Giant earphones that are obligatory. It's just what is done to seem professional or something.
6:03 what exactly are these "knee" and "ankle"? When my mom blames rheumatoid arthritis pain on upcoming rain, can I joke that it's actually because of high energy particle events from the cosmic rays, stimulating her knee joints? 😀
P.S. It could be actually an interesting topic to think about how much of a human-particle-detectors we actually are! We definitely feel things with out eyes and skin, one could see some fancy flash of light after putting head in particle accelerator (like Anatoli Petrovich Bugorski), but what about more subtle electromagnetic radiation waves?
Nice one. Thank you.
10:51 "The average distance a proton travels per one interaction is ~25.7 million years"? Was 'distance' supposed to be duration? A few sentences earlier it does specifically state the question 'how long' it takes, but then it turns over to 'distance' at the end and all calculations are in metric distances/surface areas, so it might also be that you meant 'Light years' instead of 'years'. (The on-screen answer also says lightyears)
I'm not 100% confident if "years" is wrong here, it may be an interchangeable term (even if one-way) in some specific situations such as this one...
Distance and time are interchangeable. 25.7 million years is a pretty specific distance in terms of light speed. So in this case, a half life in time also corresponds to a half-life in distance.
@@Unmannedair Thanks for elaborating on that.
distance and duration are the same thing in particle physics, since hbar = c = 1. That means it's also inverse energy (hbar x c = 197 MeV fm). That also means energy is frequency is mass (at rest), momentum is inverse distance...and if light: energy is momentum, frequency is wavenumber, and for some ppl k_B = 1, so energy is temperature (e.g., if some says "I'm a physicist!" and you say, "what's room temp in eV?", they either say 1/40, or they're a liar. Newtons G=1 means they're black-hole theorists.
Regarding hbar x c, all nuclear physicists know that above number, while high energy experimentalist might say 0.2 GeV fm, and theorist would say "1". An atomic/quantum optics physicist should say 0.2 eV nm, but probably not since they work in the inverse cm. IR ppl use that too, and microns. Below that, passive microwave ppl prefer GHz, and radar ppl dip into MHz. I skipped the THz and < kHz crowd since I've never worked with them.
edit: I skipped Dr Becky and the observational ppl, for whom red-shift, Z, is distance...but I can't forgive anyone who uses parsecs, which is no less geocentric, and more cultural tied to humans, than light-years.
Hi, yes I meant to say light years and I noticed the mistake when editing but since the protons are traveling really close to the speed of light then the proton travels basically 25.7M ly in 25.7M years so I didn't consider it to be a significant mistake to redo the whole part or distort the video in any way trying to correct the mistake.
you explain this lovely, i hope to hear more from you in the future. Collab with Anton Petrov perhaps?
I have heard somewhere that at close to light speed all the light is blue shifted to gama rays. Also will that proton not also hit photons from other light sources, that have more energy to start with?
This is like bugs hitting your windshield of your car.
So the most remarkable thing I learned is that if you travel near the speed of light, then relativity makes it so that the journey doesn't take as long from your perspective as it does for the people you left behind. You could travel the stars in just a few days... at least, so you'd experience, when actually millions of years have passed.
I have no understanding of physics but the subject fascinates me. The proton has a mass so it should be subjected to the laws of special relativity. I thought these laws predict that if - as particle with mass - you travel at speeds closer and closer to c your mass will become larger and larger and you will also start to deform in some specific way depending on the direction you're travling in. At c your mass would reach infinity. Is this correct? Or are there other laws/rules playing a role in this type of process?
Yes, though it's important to point out, that this special deformation, time dilation and increase in mass is relative. From the perspective of the moving object, it is the rest of universe that gets time-dilated, deformed and heavier.
Mass is the measure of inertia - the resistance to being accelerated by force. If you have two objects, apply the same force to both of them, and the second accelerates half as quickly, that means the second object has double the mass of the first one. When we say that "object gets heavier the closer to c is moving" what we mean is that the same force accelerates the object less and less, the closer to c it is moving.
You can still impart arbitrary amount of kinetic energy to an object. It just that, the closer to c you get, the less of that energy goes into making the object move faster, and more of it goes into making the object harder to accelerate (and decelerate).
Thank you for this interesting information.
I don't get it. Judging by what you say, this limit is purely probabilistic, and protons can't exeed it "on average". But there is still a chance that the proton won't hit any of the CMB photons in time and will exeed the limit. So the limit isn't really there. Am I missing something?