of course antimatter falls down
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- Опубліковано 26 вер 2024
- The Role of Gravitation in Physics: Report from the 1957 Chapel Hill Conference: edition-open-s...
Experiments to Measure The Force of Gravity on Positrons Fairbank and Whittburn (because the Nature paper is not online, boooooo): s3.cern.ch/ins...
12th International Conference on Atomic Physics: apps.dtic.mil/...
Observation of the effect of gravity on the motion of antimatter: www.nature.com...
Maxwell’s Dynamical Theory of the Electromagnetic Field: royalsocietypu...
Read this if you haven’t! IT IS SO GOOD THOUGH!
Anti-apples: www.slac.stanf...
Scientists Disappointed to Find That Antimatter Falls When You Drop It: futurism.com/s...
MICROSCOPE Mission: journals.aps.o...
My patreon for more videos like this (new video each month!): / acollierastro
to quote XKCD:
There are four fundamental forces between particles:
1) Gravity, which obeys this inverse square law - F(gravity) = G*(m₁m₂/d²)
2) Electromagnetism, which obeys THIS inverse-square law - F(static) = Kₑ*(q₁q₂/d²)... and also Maxwell's equations.
3) The strong nuclear force, which obeys, uh... well, umm... it holds protons and neutrons together.
4) The weak force. It mumble mumble radioactive decay mumble mumble.
Of these four forces there's one we don't really understand. It's gravity.
I never saw the punchline after listing the forces; that's golden. I remember trying to ask my high school physics teacher about the weak nuclear force (we were learning very basic quantum physics so she explained all 4 forces from a conceptual level, similar to this) and i was like 'so how is it a force? what does it do? how do we predict when particles will decay, is it just random?' and she just said 'yes', lmao.
Don Lincoln at Fermilab actually has a pretty good video about the weak nuclear force. It's mostly about how the mass of the W boson explains why the weak force is weak in terms of the Heisenberg uncertainty principle applied to pair production, but I think it's also a good demonstration of how the weak force is pretty well understood, but extremely hard to explain in lay terms. It's very well understood by particle physicists and mathematicians who read physics papers, but impossible to explain to anyone with only a high school or undergrad math and physics education.
The strong force is a little easier (I can _kind_ of understand it, and I think the best video on the subject is by PBS Space Time), and it's sort of possible to understand why it only operates at short ranges at least without a proper physics background.
Gravity, otoh, physicists understand _what_ it does (mostly), but not why or how, and even the what breaks down at the Planck scale.
This is all from my own lay perspective, of course, so take everything I say with a truckload of salt.
Moral of the story: If the equation is simple enough to make obvious sense it is only an approximation.
@@tildessmoo As someone with physics Ph.D. who took basic QED and stopped (I went in non-particle-physics directions, because even then it was obvious particle physics was in trouble) I'd say you did a pretty good job of summing it up.
The weak interaction has been successfully unified with the quantized form of electromagnetism, and is one of the biggest accomplishments of the previous century.
I actually took a thermo class from Fairbank as an undergraduate. Sometime later, a different professor made a remark in a class he was teaching: "Sometimes a theorist will tell you about some phenomenon his theory has predicted, and ask if you can detect it experimentally. Then you do a "back of the envelope" calculation and realize the effect is about 10 orders of magnitude less than you can expect to detect. And unless you're Bill Fairbank, you don't even try."
Signs I'm truly a nerd: I laughed out loud at this.
It's such a solid roast, I love it.
I was completely confused reading that, I live in Alaska and the second biggest town here (which isn’t saying a lot) is called Fairbanks, so I was very confused when you said you took a thermo class from fairbank and then you talked about Bill fairbank who I’ve never heard of, but now I somewhat get it
@@ianweckhorst3200 When taking the class, I had to train myself not to add an s to his name! In watching this video, I ended up pausing on the picture of him, to make sure I was getting it right.
I'm sorry, this is going to sound kind of random, but did he _ever_ describe anything as analogous to beebees swirling in a sink?
I about choked on the the cookie I was eating when she said "Michio Kaku would have found it in his garage when he was a teenager" Thanks Angela!
"Michiko Kaku built one! In a cave! With a box of scraps!"
"You just have to check"
Which is exactly why I still put 2 + 2 into the calculator. Maybe something changed and I wasn't aware.
Went out to get groceries half an hour ago, forgot to lock up the house. Gotta check on the calculator. Maybe somebody made off with my 2+2 and turned it into 3 somehow.
I never thought of checking with a calculator. I've been rereading Whitehead and Russell every morning.
2+2 _can be_ 5, for large values of 2. It's always wise to check.
Well 1 + 1 = 3 far vary large values of 1. 🙂
I imagine they didn't do the experiment with real hydrogen because it will be very difficult to detect individual hydrogen atoms. Anti-hydrogen nicely annihilates and releases a burst of photons indicating where it went. Normal hydrogen not so easy to detect.
So the next step should be to build the apartus out of antimatter.
That's logical but it's not the case. This is done in a vacuum to measure the rate of falling. This kind of thing has already done with matter to measure how small gravity remains consistent. Light, for example, is quantum. Single photons behave differently than photons as a whole. When done with single atoms, this quantum effect isn't measurable with gravity.
The assumption was that antimatter would behave just like matter in gravity, but it's still good to check. That's basically what she says. Her video title doesn't match what she discusses.
Protons can be detected quite easily. If they’re over say 20 keV you can just use a biased Si crystal to make a solid state detector (SSD). If they relied on annihilation alone to detect the anti-H it’s true they would have to build a modified set up to test H, but it can be done straightforwardly. They could even stack up a thin and a thick SSD and measure the mass (using the stopping power) to be sure they were counting only H. And these detector systems can be small (few cm) since we do it in space all the time (that’s what I do), where mass and size restrictions dominate our designs, often.
If they’re less than ~20 keV kinetic energy they could do something with time if flight measurements and micro channels plates, but I’d just try to use more energetic stuff if possible as SSDs are cheaper and easier, don’t require high voltage, etc.
If a single detector system could measure the pions produced in the annihilation for the anti-H test or the H directly, that would be cool.
@@mehill00That’s great and all, but aren’t the hydrogen (or anti-hydrogen) molecules really cold, and therefore moving with a tiny velocity, so that they at least have a chance of falling out the bottom before hitting the sides? I didn’t think an SSD could detect particles moving that slowly. I was rather thinking an ionisation detector might be more suitable, like the ones used in vacuum gauges?
Edit: Oops - somehow I didn’t see the latter part of your comment. I guess you thought about the low kinetic energy issue.
@@simontillson482 I haven’t read the paper, so I’m not sure how energetic these particles are. I thought I saw in one of the freeze-frame text boxes that the anti-H were ~100 keV. If the dimensions of the problem work out such that the atoms have to be much below ~1 keV my expertise breaks down a bit. My inclination would be to try to set it up the experiment to make the particles measurable using a method that either I know well or seems to be well understood by others I could work with.
This really captures the essense of science for me.
Setting up an extremely complicated, challenging and exoensive experiment to verify an "obvious" result, because we hadn't explcitly checked before, and *just maybe* an unexpected discovery would come from it.
We could have just not done this and everyone would begrudgingly accept the argument "of course antimatter obeys gravity"...
But it's nice to be really sure, even if it was a very difficult task.
This was a really good video, Angela!
Exactly. Checking the obvious is extremely important.
After all, it was *"obvious"* that heavier things fell faster for 2000 years.
Until someone (Galileo?) actually checked to make sure that heavier things fell faster.
Imagine if they did fall faster, everyone would have said "why did he bother even checking, obviously heavier things fall faster!"
But he wasted his time and checked the obvious anyway.
And it turned out heavier things DON'T fall faster!
Yeah, this is why I was frustrated they didn’t do the experiment with hydrogen yet. Maybe the values aren’t exactly the same.
Make sure to put the "I matter" in antimatter
Me saying my daily affirmations to an insect: Ant, I matter
@@BreezyBeej🤣❤️🐜
@@BreezyBeejI needed to hear this today. Thanks.
Positron thinking!
As a member of the Formicidae family I often repeat to myself, “Ant, I matter”
Angela is the kind of professor I would have had a moral duty not to procrastinate the homework
I imagine I'd shrivel up into a dried bean if she ever looked at me in disappointment over not doing an assignment.
OMG yeah, the type of professor where you're motivated by a mortifying fear of disappointing her.
she's the kind of professor I'd be sad after each class because it's over so soon
@@der6409 i'm sure she'd say "it's fine"
Such strange nerdy lads
Ah, but how do we know it doesn't fall anti-down. Please listen to my lecture where I disprove physics by making basic math errors.
nice nice nice (it says something about the prevalence of physics cranks that this is even a possible joke that means something)
Mr. Howard? Is that you?
I understand only a fraction of most the content you produce, but I *love* your delivery and passion for the subjects. The nearly-deadpan excitement is just glorious. And you often explain enough for me to get the gist. It's wonderful. _You're_ wonderful. Thank you!
hey there, good to see you here! Yes she is great!!
I’m one of those wonderful persons who love science but can’t do even basic algebra.
I love her views and explanations on different subjects. Everything she says is correct unless someone else says otherwise.
Of course patron names scroll up…but if there was ever a video for a list to fall from top to bottom of a screen, this would be it.
Happy I discovered this channel last year. Science communication done well.
patron names are anti mass
Supporters help take some of the weight off.
Antipatrons scroll down according to my theory
@@paulmalone216antipatrons are Angela's neighbours who start doing noisy yardwork while she's recording. If they come into contact with a patron they'll annihilate
@@paulmalone216Dr. Collier is surrounded by a cloud of virtual patron/antipatron pairs, some of which escape to become real patrons.
One reason this experiment is so awesome is that its taking the very first physics experiment you do ever, dropping a small ball and a big ball and seeing which one hits the ground first, and scales it up to 11. Lets take the tiniest, weirdest ball we can find and see if it still falls the same way. It's so simple yet it took years and years of effort and knowledge to even attempt for a result that is the most intuitive thing in the world. There's just something really satisfying about that idk
I cannot overstate how fun it is to learn about physics the way you make videos
I was a PhD at CERN working in the antimatter factory where ALPHA-G was located. I worked for GBAR, a rival experiment but given the small amount of physicists in experimental antimatter physics there is a lot of overlap of staff as they rotate through contracts. ALPHA was always likely to be first to report because they were adapting the original experimental apparatus that was used just for trapping antimatter atoms. The question for ALPHA G was could they get enough statistical validity and resolution to get the result. AEGIS and GBAR went the other direction, building apparatus that would have very clear resolution of but only the direction \bar{g} but the magnitude of it. ALPHA G's results in 2017 were looking hopeful but they were working out the simulations for the magnetic fake gravity. I was at the Royal Academy conference when Geoff (or maybe Jeff) explained their approach and it was one of the more interesting presentations
Thank you for the additional context. The results shown here do seem quite inconclusive when it comes to the magnitude, so I am happy to learn that there are also complementary experiments with a focus on that.
@@kunibald128 Surprisingly hard not to hope for another "crisis in cosmology" style progression where the error bars narrow more and more, isn't it?
I'm delighted to discover that "antimatter factory" is a workplace that exists.
I’m a musician with little calculus knowledge, but I came across your channel a year ago, and have watched all of your videos because you are such an amazing story teller. Keep up the good work
On Dirac's anti-matter and/or/versus anti-gravity... basically Dirac found a solution with x-squared and since minus times minus equals positive, he tried to get rid of the minus result and could not and then stubbornly accepted that it might indicate the minus variant is physically real. Whereas the string theory crowd goes "hey this is just like Dirac."
Another experiment shooting holes (🥁) in Dirac's Hole Theory! I love how you explain the need for experiments when the math says something is "not _not_ allowed."
Also: cool to see a shout-out to William Fairbank. His wife, Jane Davenport, was also an accomplished physicist-I know a decent amount about them because their son is the CEO of my former employer, Capital One.
Getting out my popcorn for another science video that mostly goes over my social science ass head but I'm here for the ride
same, I'm a concert pianist who couldn't pass chemistry or physics but here I am
It is awesome to have a trustworthy and well presented resource to point to if someone asks questions about this stuff though - "I don't know, but here's a link from this great UA-camr you'll like who does!"
@@ProteinShowdownI was slotted to take honors physics in high school and they messed up and some how gave me an A so I haven't taken a physics class sense middle school and that was like 14 years ago lol
Yo, make space. I got milk duds.
@@kombatwombat6579Milk Duds? Get this person to the front of the line.
I really appreciate your videos. Keep up the good work.
for reaal. I stumbled upon her physics books video because everything listens to me and knows that i have physics classes now. I binged a lot of her videos. they're great
omg this is really cool, I was a summer student during my masters and worked at ALPHA in 2022 just before the big ALPHA-g measurement, it's awesome to see you make a video on it c:
ive not finished the video yet, but if anyone has any questions im more than happy to answer them, to the best of my ability (and bearing in mind that im farrrrr from an expert)
I’m glad you managed to survive the shift schedule
@@regards2jimi hahaha yeah ended up with a horrendous amount of nights courtesy of niels, was a really great time though :)
About how many people do you think were working on this project at a time? Really cool work, well done!
To my basic reading the graph and text conclusion suggested they experienced 0.75g rather than 1g.... did I read that right?
@@martinwhitaker5096 yes, but the error bars pretty comfortably overlap with the 1g measurement. Also, as she mentions in the video, this is sort of a statistics based approach: the anti-hydrogen that is trapped has some temperature (meaning each anti-atom is moving randomly in some direction at some speed), so when it's released what you actually measure is the fraction of anti-hydrogen that annihilates at the bottom, vs the top and so on. Since this initial motion is thermally distributed (essentially randomised), this means that for small enough numbers of measured annihilations, the measured value of g can be pretty different from what the anti-hydrogen actually experienced.
This is my favorite channel on youtube.
Period. Full stop.
I would imagine that the reason they didn't do it with matter hydrogen is that the experiment relies on detecting the annihilation of antihydrogen against the device, whereas hydrogen obviously won't annihilate :)
They should've made the anti-device. Which is obviously the same device but out of antimatter and upside down
@@crackedemerald4930💀💀💀
I love how instead of trying to teach science, you tell us about how science kinda works.
Oh also, we leave comments because we want the algorithm to boost your content because we are engaging with it. We want you to succeed because we wish more people knew how science works
@@deltalima6703I care.
Well said. The more and better science communicators, hopefully a more scientific literate population will exist
I thought another reason why antimatter was thought to fall up was Feynman's concept that antimatter is matter going backwards in time and thus would be repelled by a gravitational field, just like gravitational attraction played backwards in time.
It also handily explained the matter/antimatter imbalance in the current universe: all the primordial antimatter is in an accelerating shell at the edge of the universe, dragging space time with it.
Nice catch with Maxwell's take on gravity! ❤
yeah that was a really intrinsic sort of way to think about it 🤯🎉
I always love the substance of your content, but I just have to say that I adore the little Casio cuts and how they're always something different and they're always bangers. That's all, hope you have a wonderful day.
I’m so glad you said they should’ve done Hydrogen too. I’m an experimentalist and I think this is a strong comment pointing out an important weakness. Not saying the work shouldn’t have been published, by any means, but it is the first thing I thought of: why are they comparing to simulations?! I hope they will follow up with both H and anti-H. If I were the referee I would have made sure they addressed why they didn’t do the H test as well (I imagine there’s a good reason; and I haven’t read it so I’m just assuming they didn’t address it or you would have mentioned it).
Thanks for continuing the great content!
Can't detect hydrogen in the apparatus ALPHA-G uses for detecting anti-hydrogen. Anti-hydrogen annihilates which gives a very strong temporal and spatial signal. Hydrogen does not so would require a very different apparatus and setup.
I, too, was like of course anti-matter falls down. Did not expect anything else. But... then again that is only my intuition and the whole universe does not have a single obligation to adhere to my intuition. Therefore, I think it is very, very, very cool if we can check and be sure. Just in case. Besides, it's a good excuse to look somewhere and we don't what else will turn up. Even if I expect nothing else. Only one way to be sure. I hope that if builds extra experience handling and working with anti-matter. Which is helpful with more difficult experiments.
Sci Show yesterday : Does antimatter fall? 😮
Angela today : of course antimatter falls down 😂
As a math person I loved hearing you explain this. It's like someone saying "well of course 2 minus 2 is 0" but no one being able to *prove it* for 50 years and now finally having a proof for it.
“Michio Kaku would have done it in his garage when he was a teenager” is just perfect. No notes.
At 24:33 you ask them to repeat the experiment with protons & electrons. I think the reason they didn't is it's hard to detect atoms of hydrogen. Anti-hydrogen gives off a signal when it annihilates. Hydrogen doesn't annihilate.
Technically, antimatter doesn't just annihilate on its own either.
Annihilation occurs when a particle meets its anti-particle.
Anti-hydrogen + Anti-hydrogen = nothing happens
Same goes for Hydrogen + Hydrogen.
You need Anti-Hydrogen + Hydrogen (or Anti-Hydrogen + a proton + electron) for annihilation.
The reason the trapped anti-matter annihilates is because the surrounding experimental apparatus is made of matter.
We could trap hydrogen in the same way and have it annihilate if it was surrounded with some anti-matter, but that's a lot more work.
A fellow fan of the Corning Museum of Glass I see.
Their channel has a lot of very satisfying and educational videos.
I can't believe I'd never heard that snippet you read from Maxwell. That was a perspective I needed for some real intuition to fall into place. Thank you!
I agree, the big leap forward was Maxwell's interpretation of the electromagnetic forces, he was a genius. It took an abstract mind like Einstein to hold those ideas in thought experiments and play them out in the greater universe. They should get equal credit for the creation of modern physics.
I could listen to Dr Angela all day. I love her teaching style and she's so funny and honest. Wish all my teachers where like her... If only! You would love County Durham to teach..x
If even antimatter falls down,
How do we stand a chance?
Squatting in a well at stars,
Forgotten romance.
A wrinkle in my eye helped me to touch the sky
Heart broken open into peaces on this plane
Met my anti matter self and dissolved into pure light.
31:50 I don't think you understand just how amusing your description of the scientific process is here. "You need to observe it, you need to touch it, and poke it with a stick" might be one of the best things you've ever said.
Ok but how fun would it have been if we lived in a universe where antimatter falls up. I feel like that would be just a way quirkier and therefore better universe, personally.
And would neatly explain why the observable universe seems to have little or none of it. We've been looking _around_ for all the antimatter but we forgot to look _up._ It's been collecting on the ceiling this whole time.
One of my professors is a lead scientist on this experiment and it's cool as hell
Another really good video!! What I particularly liked is your read through of Maxwells thoughts on repulsive gravity. It's always so fun to see people at the cusp of fundamental discoveries in physics grappling with concepts that we take for granted today!
"so those anti hydrogen hang out in the trap" is definitely in my top 10 favorite sentences 😂
Maxwell left us on a cliff hanger
Hello from Dr. Dave! Found you because Dave did a vid about Formscapes and he had mentioned you in some rubbish video of his. I love learning about science stuffs, and so glad to collect yet another person willing to put create science content on youtube! TY!
Excellent summary as usual! I think a lot the confusion for people guessing antimatter might key to antigravity is mostly due to the name we gave antimatter. When you get down to it, the only thing “anti” about antimatter is the fact that they carry the inverse charge of the particles we commonly interact with, which it coeliminates as a result. There’s no fundamental inversion of any extrinsic properties besides that. “Antimatter is matter” is something people should hear more often!
well, and the fact it annihilates with normal matter. Also I vaguely recall a particle interaction that's been shown to have chirality that's reversed with antimatter.
A better explanation is that antimatter is regular matter, in a mirror, going backwards in time.
@@psymar How is it going back in time? That sounds like something that Angela would read then pause and look at the camera as she sighs.
@@ZabivakaPirate69 she literally did almost exactly that in her previous video on antimatter
@@psymar particles of normal matter annihilate with their own anti-particles as well, that’s not different. There are other things that are different, but you didn’t mention any of them.
If we want anti gravity we need negative mass, not anti matter. Which probably doesn't exist. The equations technically work with negative mass, but it had some wonky properties.
You make science fun and interesting. No nonsense, I learn every time I watch a video.
I remember when I played space engineers and noticed the game had anti-gravity (you just put space rocks below the gravity generator), so my first thought was that I'd use it to build an infinitely accelerating spaceship.
It's kind of wild that people are suggesting it as a serious concept without first finding ways to resolve the obvious flaws, but it's nice that this wasn't the only alternative outcome of the given experiment.
Eh, I doubt it wouldve resulted in some sort of perpetual motion device, for the same reason magnets dont.
Gravity and magnet fields dont do any work.
In space engineers you can also make a gravity drive with the rocks infront of the gravity generator, it just goes the other direction. The gravity generator is the common denominator here
ironic that the only thing not anti in antimatter is the actual matterness of the matter : it's mass 😅
What a great sense of humor, love it!
I'm in biophysics. I turned on your video to have some background noise while I reviewed some notes. No notes were reviewed. I love your vid, your enthusiasm for science is few and far between
That "OK😐" at 30:49 is great.
Thank you for what is undoubtedly the definitive definition of physics: Physics == poking the universe with a stick!
If the electric field is too dominant for charged particles then just measure the gravitational effect on an anti-neutron 😎
yes! the problem is just about how to capture the anti neutrons since it also is not affected by magnetic fields lol
free neutrons are not stable particles and will decay over a short amount of time (mean lifetime is about 900s) so probably not a good idea
@@christiaankoningen4632 are you sure we can't get a peek of how they fall down in the 15ish seconds they stick around for? i bet their decay products are a good way to detect where they end up after they fall :)
Free neutrons would decay before you could do the experiment, though.
And if you could male enough of them fast enough to run the experiment, you could already have done it with anti-hydrogen.
Yeah, one issue is that they explode. The other is they’re extremely hard to make in the first place. The only way I can think of to synthesise an anti-neutron would be to perform fusion using anti-hydrogen. We can’t even do that with ordinary hydrogen!
Your videos make my day Angela, thank you so much :))
literally can listen to her talk about physics all day
Long time ago in Mexico there was a crazy guy from UNAM who wrote a thesis on repulsive gravity. He was really convinced of it!
Alcubiere?
pasa chisme
which is fine, this is how science works, you must just be ready to be disproven. (or better yet try to proof yourself)
I always thought it was for historical reasons that they get lumped into one... From before the formal treatment of antimatter in QFT where the negative energy solutions to the Klein-Gordon (this equation would probably be an interesting video topic also in connection with how Schrödinger dismissed the relativistic KG equation because of the negative energy states) and Dirac equations gave us things like backwards in time travelling electrons and the anti electron as a hole in the Dirac sea. I thought someone just said "ah neat, negative energy means negative mass... I bet it pushes odinary positive mass matter" and a journalist did the rest.
It bothered me so much that we didn't know this basic fact about antimatter. So when I first learned about this result from the CERN UA-cam channel, I was like "wait, is this it? We finally know? And I'm randomly learning this from my UA-cam subscriptions? Why wasn't this on the news? Heck, why didn't anyone call me?!"
Maxwell is a legend
And he had a silver hammer! There's a song about, and everything! =:o}
I'll just add my voice to the chorus of approval for Dr. Collier's videos. I have seen many of them, and have not been disappointed. Entertaining, ecucational, and a bit humourous. This one is just another winner. Carry on!
Principia Mathematica reader disappointed that 1+1=2
Still waiting for the article that says "Physicists devastated that recent experiment demonstrates friction works exactly the way we thought it would" because "without friction we could make perpetual motion machines"
Great video... you asked them to do the same test with regular hydrogen. You probably realized it right after you said it, but there's a very good reason why they didn't do that.
Anti-hydrogen escapes the trap and is detected... how? Because it annihilates creating a detectable flash.
Regular hydrogen doesn't do that... it's much harder to detect a couple hundred hydrogen atoms doing anything.
Just make an identical machine out of anti-matter. Simpels.
nah
If it falls up, you win a Nobel Prize. If it falls down, people tell you 'I told you so'. - Prof. Jeffrey Hangst
"Antimatter" is not a very good name for antimatter. In common parlance, I think mass is the property most closely associated with matter so, if you call something antimatter surely the most obvious (but wrong) implication is the mass is negative. BTW I'm looking forward to reports of anti-dihydrogen (or should that be di-anti-hydrogen).
You are correct.
I personally think "mirrored matter" or "reversed"
"Negetive" has the same issue as "anti" But "anti" and "negetive" have the advantage of immediatly drawing the connection to antimatters most immedeatly observable trait. It destory's an equal mass of matter!
I think English is just too binary to express the physical world accuratly; an unintended side effect of adopting the Guettenburg press and typeface.
(for those who dont know; Engilsh, and most European languages changed dramatically by using words that used the alphabet that was shared with the German presses typeface as replacements. Wife is a good example, it used to refer to a man who was homely and perfered the company of a man and a feminine style of dress, homely is another it used to mean what it said on the box a home maker...)
I agree that the "anti" part can easily give false impression of the properties of the stuff but at the same time I kinda think its the perfect name for something that can't really coexist with the matter we are all made of
@@AnonymousAnarchist2 the first person to hypothesise it called it 'contraterrene matter', i.e. non Earth-like matter.
I wish I could teach everyone to think the way you do. The most important concepts that have helped me in multiple careers are also your mantras.
E.g. "You have to check" is one.
And I am especially impressed with your.comment that CERN should have run experiment on Hydrogen as a control
I know you are a theoretical physicist but if you decide to do anything else, you would also be a superstar in that. Do not limit your ambitions exclusively to theoretical physics. Your are young and opportunity is endless
Probably because of the Dirac Sea interpretation. Vacuum is normalized to have zero mass and charge. Once you create particle, you pull it out of vacuum. this creates a hole in vacuum. So the conservation of charge requires particles and antiparticles have different charges. But mas is conserved too, so the mass conservation would require antiparticles to have negative mass, if the Dirac Sea interpretation was correct.
When I heard about that, your video title was my exact words
I guess the angle some of the articles were coming from is: Wouldnt it be more exciting if they found and empirically verified a crack in general relativity? Though I suppose it is cynical to label this as disappointing rather than just less thrilling, and given the chances of such a thing happening, the fact it didnt probably should have been a foot note rather than the thrust of many of the articles. You know, itd be thrilling if a winning lottery ticket landed in my hands, but given Ive never played the lottery Im not disappointed it hasnt and wouldnt make a habit of talking about it to everyone.
I'm not going to lie, I'm a little disappointed that antimatter isn't so upside-down that it doesn't fall up...
The next test is to gather enough antimatter into one place that tis gravitation can be measured. Does it pull or push things away?
What do you mean? We know its properties. It has mass the exact same way "normal" matter has mass; therefore, why in the world would it "push things away"?
I'm sure there's a better way than the Cavendish experiment, but right now I'm picturing vials of antilead for the small stationary weights. Even leaving aside how difficult it would be to make antilead, to actually imitate the original Cavendish experiment would take over 1½ kg of antimatter!
I know, we'd be using a more streamlined modern setup with lasers and much smaller weights (and probably vials of antihydrogen for the small weights, then subtract the effects of the mass from the matter of the vials themselves), but just imagining someone building a torsion scale with 1½ kg of antilead seems hilarious to me for some reason.
ain't no way
you haven't understood the nature of antimatter.
@@tildessmoowhat are you making the vials out of?
Of course you check the veracity of statements made, even by eminent people.
“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.” (Arthur C Clarke)
The motto of the Royal Society is “Nullius in verba”, or loosely “Take nobody’s word for it”.
Aristotle said a lot of things that were taken as true, until the 17th century when people began to test them - and discovered errors.
Many exciting discoveries were made when assumptions were checked, as in the Michaelson-Morley experiments.
I never really understood why mathematicians would always make these long and complicated proofs for things that were so obviously true, until 8th grade. I was in a special help math class, and we had a long term substitute who had not taught math for a very long time. We were learning about slope, or y=mx+b. I don't really remember how it all works anymore, but I'll do my best to explain it for anyone who doesn't understand it already - (So imagine a grid with a vertical line running down the center labeled y, and a horizontal line in the center labeled x. You'd be given a line that runs through the grid, and your goal is to use a function to describe where the line is, and where it is not. The line is always Straight. In the function, y=mx+b, m accounts for the angle of the line (so if you Imagine the small squares the grid forms, does the line go from the top left corner to the bottom right, or to the bottom right of the next square down, or the third down, or the third down and one to the right?), x and y equal the coordinates of a specific point on the line, and b accounts for the vertical placement of the line.). At the time of the sub, we were learning how to deduce the value of b when we are only given the values of m, and the x and y values of a single point. Now, the way b was explained to us was that b was the y value when it is on the y axis, so my first thought was y=b when x=0, because the y axis is placed on zero, but when I told the sub this, she told me I was completely wrong. So because I have no control over my own stubbornness, I tried to prove her wrong. She actually got the problem wrong using long division, but she wouldn't accept my answer without proof. Now, the way solved it was to literally trace the x coordinates back to the y axis, which I was able to do in my head, so the only way I could show my work was to write out every coordinate from the point we were given to the point where x is 0, which took me until my peers had left for lunch. She admitted I had the right answer only when she realized the mistake she made in her equation, but she still claimed I was wrong that y=b when x=0, because I had no proof. So every class we did this - she'd get the answer wrong, I'd say so, she'd deny it, I'd stay after class to prove it, she'd admit she was wrong (but only to me and not the rest of the class the next day), tell me my method can't work every time, and repeat. The entire time she was there, she never let me turn in a test without filling the pages with coordinates, she never admitted my way worked, and I never learned how to do long division. She did think I was the smartest student in the class, which somehow resulted in me getting booted into a normal class that was an entire unit ahead. I had no friends, no idea what we were doing, and I still can't do long division. So because people like her exist, we have to prove that 2+2=4, and that antimatter falls. You know what, I take it back, I understand this crap better now than she did then, damnit man, school failed me.
WTF! "y=b when x=0" is by definition. That sounds like she didn't understand algebra; wasn't she _supposed_ to be teaching it!
Oh god, that's so rough.
FWIW, I'm pretty great at math and I can't do long division either. I mean I can figure it out again when I need to (I bet you could too), but yeah long division sucks 😂
That sounds incredibly frustrating, but with all due respect, that's NOT why we have to prove stuff like that 2+2=4 and that antimatter falls down. It's not about convincing stupid people (if it were, it wouldn't be worth the time, cost, and effort). The reason people spent time, a century and a half ago or so, "proving" that 2+2=4 was to show that, contrary to Kant's idea of the synthetic a priori, arithmetic is just logic plus an appropriate set of definitions. And the reason ALPHA proved that antimatter falls down is that we didn't actually know that yet, even though it was thought overwhelmingly likely, and therefore was worth confirming.
I mean long division is just dividing a number as much as you can, adding a zero to the left of the remainder, dividing that as much as you can, rinse and repeat. It is mainly tedious. Which can describe a lot of math by hand.
Edit: I now see why some people find long division hard. It requires a solid grasp on quite a few math skills I take for granted.
@@bestaround3323 Yeah, but proving from first principles (i.e. pure logic plus an appropriate definition of numbers) that this algorithm WORKS and gives the correct answer is much more difficult. Hence Russell and Whitehead spending hundreds of pages on preliminaries before they were in a position to prove that 1+1=2 in their Principia Mathematica.
Your enthusiasm is infectious, cute, and makes the video more fun to watch. The delivery of the material was awesome and I learned a lot, so ty. This IS a really cool experiment (OF COURSE IT FALLS DOWN). And your Love for String theory is always fun to see.
This is such a good channel.
Indeed
I really appreciate that we have a paper describing in exact detail how they dropped some antimatter to see if it fell and it did.
I'm not an expert of that field either but I don't think that experiment works 1to1 with regular hydrogen. Based on your description it relies on the annihilation to measure the individual Atoms, so if we did it with normal Hydrogen we'd need the detector to be made from antimatter to annihilate the falling atoms. Which is quite obviously impossible (currently).
We can measure the normal hydrogen in other ways that don't require anihilation.
Also, we *know* that matter falls down.
@@garak55 I just said it's unlikely you could put it next to eachother 1 to 1
But while we are at it, just out of curiosity, how do we measure single Hydrogen atoms ?
@@boredstudent9468 but it's an interesting question nonetheless
Your enthusiasm is contagious! I had to watch the whole video!
Antimatter falling down just confirms General Relativity and it still applies. The curvature of space-time doesn’t care the polarity of the matter. It all just rolls downhill.
Fun thought, when you were reading Maxwells explanation of gravity, I was reminded of the Virial theorem. It’s like Maxwell was laying the foundation for both General Relativity and the Virial theorem.
Never miss a chance to come for Michio Kaku
But what IS down? Vsauce, Michael here.
"Which way is down? and how much does down weigh?" - I may be misquoting but I am pretty sure he starts off a video with that.
Simple, ask an Aussie which way is down.
Then its the other way.
Yes, we all expected that. But you never know...the accelerating universe expansion was a complete surprise.
38:00 "in this paper, they mention something I've never heard of: the microscope" -dr. angela collier
I was wondering when you were going to cover this. One of those stories where nobody was surprised at the results... but you still need to check just in case. Would have been pretty cool if it went the other way.
Probably a nominee for an ignobel prize.
I think i can help you out on the question of why people confuse antimatter with antigravity.
You see, there's alkaline water... and then you add lemon.
totally a 'my god, it's full of stars' moment. we glimpse a truth of the universe and it's utterly beautiful. this is why i love science.
Betzalel Bazak, a physicist working in few-body systems in ultracold atoms and nuclear physics, was seriously injured yesterday while fighting in Gaza. I hope he gets well!
I looked him up and he seems to be Israeli. Are you rooting for an IDF terrorist?
come on. please don't bring up this topic on a cool antimatter video, because I don't think we want to have the discussion about what the destruction of every single university in Gaza and killing of hundreds of academics does to the study of particle physics
unconditional ceasefire for the sake of all of humanity
I LOVE the waterfall you used for the cover. I visited it too many times to know it from a glance. Either that, or there are too many waterfalls look-alikes around the world.
oh no, how dare you try to have fun with your youtube channel joking about concepts such as quantum gravity. This is totally unacceptable, I've already informed the board of math people, be ready to be cancelled ;p
Thank you for proposing doing the same experiment with normal matter!! I was mentally shouting that for half the video.
I started this video when it was posted "4 minutes ago" and just finished watching it all the way through, meaning the 72 comments that have already been written are (mostly) coming from people who haven't watched this video. After finishing it, my question is, if gravity affects matter and antimatter identically, how can anyone be sure that galaxies are matter and not antimatter (or anything else that's at a great distance)? Couldn't there be pockets of space where one form of matter predominates? Or, just.. no? Idk. Just wondering.
The fundamental property of antimatter is it turns you into a werewolf.
Another great video!
Paper is really cool. Figures are great, though the histograms were a bit confusing; could do with a violin plot imo... ;)
Why a violin plot?
@@AlanTwoRingsShe talked about violin plots in a previous video. It doesn't go well for them.
@@p-j-y-d I know but I feel like making a joke out of it kind of misses the point of the video, doesn't it?
@@AlanTwoRings Making a joke out of violin plots missed the point of the video? I guess explaining a throw away tongue-in-cheek comment kills it dead. :D
So much of this goes over my head, but I still love your videos because you do such a stellar job of communicating complicated subjects.
first
3:21 Yes! We don't just assume we know things in science, we need to prove our predictions! Such an important part, not just testing what we don't know yet but confirming we know what we think we should know.
"you need to poke it with a stick." so perfect.
If you don‘t know what is…
Pure gold! Especially those final 5 minutes.
(As for the first part of the video, it seems to me that one could speak a bit more critically of those efforts in 1950s and 1960s. Not to knock the period itself, which included some absolutely astonishing experiments with neutrino detection that I LOVE. But experiments such as those mentioned @4:05, which aspired to separate the electromagnetic influences on a positron from the gravitational influences on it?? Those were just incredibly stupid and wasteful of resources, given the "orders and orders and orders and orders of magnitude" at play, which are duly mentioned @5:02.)
"Mitchio Kaku would've done it in his garage as a teenager." I'm dead laughing. It's fine. Of course antimatter falls down. 💯🎉 😂
Love the CMOG bag behind you!