I’ve been lecturing today at Manchester - special relativity - and for no good reason other than I want to post stuff here, here’s my lecture notes introducing the concept of invariant mass :-)
Replies
I can do that in my sleep….
nov 16, 2024, 7:38 am • 0 0 • view
So you do Wordle and I can't. No big deal.
nov 15, 2024, 3:59 pm • 0 0 • view
Yeah, understand all of that... 😂
nov 15, 2024, 7:37 pm • 0 0 • view
Well that brings back a few memories - I was even saying the last bit before I reached it. Haven't done any relativity for 40 years!!!!
nov 15, 2024, 3:56 pm • 0 0 • view
My daughter was there today and she confirms that you are the real Professor Brian Cox.
nov 15, 2024, 8:54 pm • 0 0 • view
My daughter is in your lectures!
nov 15, 2024, 4:09 pm • 0 0 • view
i see letters, i see numbers, i see Hieroglyphs what i dont see is anything i will ever understand :)
nov 15, 2024, 4:58 pm • 0 0 • view
Please can you look after them took me 20 mins to write this down.
nov 16, 2024, 1:59 pm • 0 0 • view
Hmmmmm..... I think there's an error in line 4 🧐🧐 I will defer to our mutual friend @marvinh2g2.bsky.social He marvels at my grasp of Maths 😂🤣😂
nov 17, 2024, 11:09 am • 2 0 • view
Eloquent, intelligent AND you have legible handwriting. The complete package 😎
nov 15, 2024, 9:07 pm • 0 0 • view
So, I fed that into ChatGPT and asked it to break it down into layman’s terms, which I’m sure it did, but my head is still aching. You do you, and I’ll just sit down here and nod, smilingly. 🤣😂
nov 15, 2024, 7:24 pm • 0 0 • view
Makes sense to me. 😵💫
nov 15, 2024, 3:56 pm • 0 0 • view
See me after class…..please
nov 15, 2024, 3:55 pm • 2 0 • view
I may need a calculator!
nov 15, 2024, 3:48 pm • 0 0 • view
That some people can understand this is enough evidence to prove the existence of alien life for me
nov 15, 2024, 5:50 pm • 1 0 • view
Yup
nov 15, 2024, 6:27 pm • 0 0 • view
I think this proves this is the real account!
nov 15, 2024, 3:41 pm • 5 0 • view
Only if you understand it..
nov 15, 2024, 4:39 pm • 1 0 • view
Mass is an invariant quantity, meaning it remains constant regardless of the object's velocity innit.
nov 15, 2024, 4:49 pm • 4 0 • view
I'm a bit wiser....thanks
nov 15, 2024, 5:15 pm • 3 0 • view
All Greek to me!
nov 20, 2024, 12:52 am • 0 0 • view
nov 15, 2024, 11:26 pm • 0 0 • view
Very neat writing. You can have a neutron star sticker.
nov 16, 2024, 12:01 am • 0 0 • view
Your handwriting is a lot more legible than I thought it would be!
nov 15, 2024, 5:08 pm • 0 0 • view
all geek to me ... :-)
nov 15, 2024, 3:51 pm • 1 0 • view
😉
nov 16, 2024, 12:08 pm • 0 0 • view
Makes sense to me.
nov 15, 2024, 8:24 pm • 0 0 • view
My son was in that lecture. I will ask him if it made sense !!!
nov 15, 2024, 3:58 pm • 1 0 • view
I’m trying to incorporate the concept of invariant mass into a “yo momma” joke, I’ll let you know how I get on
nov 15, 2024, 3:41 pm • 4 1 • view
Yo momma has such a large invariant mass that …..
nov 15, 2024, 3:43 pm • 14 1 • view
Dunno, something about a naked singularity maybe? Let me work on it, is Michio Kaku on here?
nov 15, 2024, 3:53 pm • 0 0 • view
She generates her own gravity field ?
nov 15, 2024, 3:45 pm • 9 0 • view
The problem with that joke is that everything with mass or energy generates its own gravity field.
nov 15, 2024, 4:35 pm • 8 1 • view
Could we redefine an AU as an “Ass Unit” then ?
nov 15, 2024, 6:15 pm • 0 1 • view
Everything is yo momma.... QED
nov 15, 2024, 4:49 pm • 3 0 • view
10 points to griffithsdor!
nov 16, 2024, 5:28 pm • 1 0 • view
How about Yo momma's invariant mass is so huge, when she walked into the particle accelerator, they didn't need collisions???
jan 1, 2025, 10:41 pm • 1 0 • view
I think it works without a punchlie
nov 15, 2024, 4:41 pm • 0 0 • view
I'll continue with the TV stuff. I repeat watch 'Black Holes : Heart of Darkness' though. Nothing is certain, thank you 😊🙀
nov 16, 2024, 2:46 pm • 0 0 • view
I said to family I had to get a 4-in-1 multicolour pen to be able to be good at physics. Look at your notes…legible & coloured. They said that it wouldn’t make any difference, all the problems would appear blue coming towards me & red as they flew over my head. That’s relatives for you
nov 16, 2024, 7:51 pm • 0 0 • view
I remember when I understood that :)
nov 15, 2024, 4:35 pm • 0 0 • view
I go to mass on a Sunday
nov 16, 2024, 10:33 am • 0 0 • view
You lost me at "concept of"....🤷♂️😂
nov 15, 2024, 5:03 pm • 0 0 • view
42 is the answer right? I would love to study physics but I'm totally rubbish at maths and this just looks terrifying!
nov 15, 2024, 3:41 pm • 3 0 • view
My brain after looking at that:
nov 15, 2024, 3:49 pm • 0 0 • view
Looks good to me! 😄
nov 15, 2024, 3:41 pm • 1 0 • view
I was going to make a clever comment, but instead I'll blot my copy book by saying that there are only 40 days till invariant Xmass.
nov 15, 2024, 4:02 pm • 1 0 • view
Nice.
nov 15, 2024, 4:03 pm • 1 0 • view
🤣🤣🤣
nov 15, 2024, 5:06 pm • 0 0 • view
I wonder how long the lecture was based on so few notes.I reckon it was really long, and I wouldn’t understand any of it!
nov 15, 2024, 11:15 pm • 0 0 • view
Interesting - not a concept we covered in my 70s Physics degree
nov 21, 2024, 11:09 pm • 0 0 • view
I adore you but most of your stuff goes over my head no matter how much I persevere so here's a pic of my laptop
nov 15, 2024, 5:03 pm • 0 0 • view
I adore you but a lot of your items go over my head so here's a picture of my laptop.
nov 15, 2024, 5:00 pm • 0 0 • view
Impressive! Thanks for sharing it to us!
nov 15, 2024, 7:54 pm • 0 0 • view
Well you’re just showing off 😆😆
nov 15, 2024, 5:54 pm • 0 0 • view
seems about right!
nov 15, 2024, 5:30 pm • 0 0 • view
I'll have trust you on that, but I will try harder!
nov 16, 2024, 2:44 am • 0 0 • view
You didn’t carry the 7.
nov 15, 2024, 7:22 pm • 0 0 • view
Waaay over my head! My 11 has discovered your ‘solar system’ programme on iPlayer and has absolutely loved it. He’s now impressing his science teacher with everything he has learned from you.
nov 15, 2024, 9:53 pm • 1 0 • view
That’s great - say hello from me !
nov 15, 2024, 10:01 pm • 3 0 • view
Absolutely will do, thank you!
nov 15, 2024, 11:11 pm • 0 0 • view
💯 ... Have a gold star ⭐
nov 16, 2024, 7:40 pm • 0 0 • view
o my gudniss
nov 15, 2024, 7:11 pm • 0 0 • view
Thank you for sharing!!
nov 15, 2024, 6:32 pm • 0 0 • view
Colonel Mustard, in the library with the lead piping.
nov 15, 2024, 11:47 pm • 0 0 • view
Ahh yes yes I see. Hmm very interesting. I see you’ve used squiggly line, p, broken rectangle theory. Parabola, delta, theta, equal, divide, denominator, math, math- mathy math. science. Indubitably my good sir.
nov 16, 2024, 5:26 pm • 0 0 • view
Nimpse !
nov 15, 2024, 3:42 pm • 0 0 • view
Jesus I'm glad my college days of physics and maths are long over
nov 15, 2024, 3:51 pm • 0 0 • view
It’s great stuff :-)
nov 15, 2024, 3:51 pm • 2 0 • view
And I love how it gets down to E=mc^2 when the thing isn't moving! Wonder what happens if m<0? Still positive energy (?) but possibly repulsive gravity?
nov 15, 2024, 3:59 pm • 1 0 • view
Also note that E =gamma mc^2 would appear to imply that massless particles should have zero energy - BUT for massless particle travelling at c, gamma goes to infinity and so the expression is undefined. Then we have E =pc from the equation in the notes. Nice :-)
nov 15, 2024, 4:03 pm • 4 0 • view
Indeed!
nov 15, 2024, 4:05 pm • 0 0 • view
Yes. That looks about right 😜
nov 15, 2024, 3:40 pm • 9 0 • view
I have zero idea but I'm god damn impressed. Great to see you over here also!
nov 15, 2024, 10:03 pm • 0 0 • view
I appreciate well written notes even when I have no idea what’s going on in them lol
nov 16, 2024, 1:14 am • 0 0 • view
9/10
nov 15, 2024, 3:42 pm • 1 0 • view
I get overwhelmed by long division so this makes me feel physically unwell.
nov 15, 2024, 4:21 pm • 0 0 • view
Me in said lecture
nov 15, 2024, 3:48 pm • 0 0 • view
Yeah, that's exactly what I would have said as well.
nov 15, 2024, 4:49 pm • 0 0 • view
Ok 👍 i think this is probably the coolest way to verify ID 😂 👏
nov 16, 2024, 2:38 pm • 0 0 • view
Totally irrelevant, but here is thing what bugs me: I can't push myself to believe that time ends in black holes. Maybe I got the idea of black holes bad, but in nature nothing stops. Maybe time just slow down immensely. I mean even particles are moving in absolute zero.
nov 15, 2024, 3:53 pm • 0 0 • view
42 😀
nov 15, 2024, 3:48 pm • 0 0 • view
I don’t speak whatever language that is. 😒
nov 15, 2024, 4:46 pm • 0 0 • view
I need to lie down in my own space and take the time to digest this…
nov 15, 2024, 4:10 pm • 0 0 • view
Does it make toast Brian?
nov 15, 2024, 3:44 pm • 1 0 • view
Invariant Mass is what I was dragged to every Sunday morning growing up
nov 15, 2024, 3:46 pm • 7 0 • view
Sigh . . . I wanna attend one of your lectures based solely on the fact that your writing is legible (salutes) ;0)
nov 16, 2024, 8:24 am • 0 0 • view
I won't pretend to understand that, but it does at least prove that your account is the legit one and not an imposter 😆 Welcome to Bluesky!
nov 15, 2024, 3:45 pm • 0 0 • view
Your handwriting is very neat. How did you manage that, growing up in an era when you were either clever and got put in the clever group that did maths, or those who they had prematurely decided were only good for handwriting practice.
nov 16, 2024, 10:07 am • 0 0 • view
I wouldn't worry about posting stuff here for no good reason. To quote your former band-mates: "we don't need a reason" 😜
nov 15, 2024, 3:57 pm • 1 0 • view
Makes perfect sense to me 🤯😃
nov 15, 2024, 3:48 pm • 0 0 • view
The answer is 14. Cheers
nov 15, 2024, 3:40 pm • 9 0 • view
Isn't is always 42? ;-)
nov 15, 2024, 3:45 pm • 16 1 • view
Yes it is😂
nov 15, 2024, 3:56 pm • 2 0 • view
😂
nov 15, 2024, 4:31 pm • 1 0 • view
I didn’t even click there haha
nov 15, 2024, 4:06 pm • 1 0 • view
Beat me to it :)
nov 15, 2024, 3:49 pm • 2 0 • view
Now you own me a steak at The Restaurant at the End of Universe. 😁
nov 15, 2024, 3:56 pm • 5 0 • view
Okay lets meet the Meat.
nov 15, 2024, 10:17 pm • 3 0 • view
Yes, limjahey forgot that we're working in 3 dimensions. So 14x3 = 42.
nov 15, 2024, 6:33 pm • 2 0 • view
Bloody 3 dimensions I always forget about them
nov 15, 2024, 6:47 pm • 1 0 • view
Ha ha!!
nov 17, 2024, 11:02 pm • 1 0 • view
I can just about cope with special relativity, but I’m finding invariant mass a step too far…….
nov 16, 2024, 7:10 am • 0 0 • view
^ If you like this post your IQ raises by 1pt
nov 15, 2024, 4:44 pm • 0 0 • view
10 years ago since I was there in that lecture hall! Good to see the Jeff collaborations continuing
nov 16, 2024, 2:31 pm • 0 0 • view
It’s a recipe for Fruit Tarts, I tried it today and here’s the result.
nov 15, 2024, 10:07 pm • 0 0 • view
Ooh err....
nov 15, 2024, 7:02 pm • 0 0 • view
Thanks for posting this, it brings back many happy memories from 45 years and 395 000 000 metres ago
nov 16, 2024, 11:19 am • 0 0 • view
Invariant mass, the curse of middle age! 🫣
nov 16, 2024, 2:46 pm • 0 0 • view
Thanks for posting I was just thinking about the invariant mass 😉 Brilliant you are, wish I understood it.
nov 16, 2024, 4:35 pm • 0 0 • view
Nah. I'll just stick with the stuff you do on TV I can understand some of that
nov 15, 2024, 4:17 pm • 0 0 • view
I can tell from this that you are quite smart!
nov 15, 2024, 7:53 pm • 0 0 • view
Well, my head just exploded 💥
nov 15, 2024, 3:41 pm • 1 0 • view
You have very neat handwriting.
nov 20, 2024, 9:28 pm • 0 0 • view
My partner says he is reminded of Emmy Noether. If I were a better mathematician I expect I would be too.
nov 17, 2024, 11:15 am • 0 0 • view
I have not passed this test 😞
nov 16, 2024, 7:49 pm • 0 0 • view
Yeah. I'm just about at the level of your spinning egg experiment.
nov 16, 2024, 12:03 am • 0 0 • view
Lol, makes perfect sense to me.
nov 15, 2024, 6:41 pm • 0 0 • view
Pretty obvious really 😬
nov 15, 2024, 4:20 pm • 0 0 • view
nov 15, 2024, 11:38 pm • 0 0 • view
Oh silly! I’ve spotted your deliberate mistake 😄
nov 15, 2024, 3:56 pm • 1 0 • view
I got to the bit that stated "of course the answer is yes." So I though, well, ok then it's solved, time to move on....
nov 15, 2024, 4:38 pm • 0 0 • view
🤔🤨🤔 Is the answer 42? 🤯
nov 15, 2024, 3:44 pm • 0 0 • view
2+2=4. ; )
nov 16, 2024, 4:16 pm • 0 0 • view
The equations always look prettier if you use natural units ;-) I think I've been watching too many Leonard Susskind lectures!
nov 16, 2024, 6:47 pm • 0 0 • view
Stupid question alert. Is the mathematical system we use the most appropriate for calculations like this. You could do maths using roman numerals but that system seems more complicated and less intuitive than the Arabic numerals we use instead. Could another system of mathematics be more suited?
nov 16, 2024, 1:54 pm • 0 0 • view
Think I need a beer to help me with that!
nov 15, 2024, 3:42 pm • 0 0 • view
Keep up the great work Prof. Cox. BTW, I have just accurately calculated the exact masses for the electron and muon neutrinos. I figured this out in Beta - decay and muon decay. Thank you
nov 15, 2024, 3:43 pm • 0 0 • view
I just see little ants on a sheet of paper.
nov 16, 2024, 2:44 pm • 0 0 • view
I can understand a fair bit of this, however the calculus at the very top has always flummoxed me completely. Is there an easy way to understand it?
nov 15, 2024, 3:44 pm • 0 0 • view
It’s just the rate of change of position generalised to spacetime. So velocity = dx/dt basically. Think miles per hour …
nov 15, 2024, 4:38 pm • 2 0 • view
Thank you. That certainly helps.
nov 15, 2024, 4:54 pm • 0 0 • view
I preferred the cat.
nov 15, 2024, 3:57 pm • 1 0 • view
"Getting past C1 is all about the mass". Do we eliminate the mass of the vehicle or the fuel. Maybe we should look for the point where mass and velocity are equal. Using a "spit pea' approach where mass suddenly drops while velocity increases in an equal > 1 amount.
nov 15, 2024, 3:55 pm • 0 0 • view
Are you one of those Russian bots 🤖 l keep hearing about?
nov 15, 2024, 10:29 pm • 0 0 • view
When you read maths, is it more like a language? Or in your head you just counting that up like 2+2?
nov 15, 2024, 3:46 pm • 1 0 • view