I would happily listen Ed Copeland breaking the news of the imminent end of the world with his soothing voice and still feel safe and cosy.

"Science is about aesthetic." (5:50) A memorable quote.

I love it when they show the pictures of stars :D and you can sometimes see a spectrum, it's really beautiful :)

Great video. It would've been really nice to see an image of Einstein's equation with the lambda in it.

that professors voice is so soft its great for asmr. get him to make more vids

5:05 I wish he'd say 'cubic centimeter, or sugar cube's worth of space' rather than "centimeter cubed" which probably doesn't mean much to most people. Gosh I love these videos the most of anything on youtube. I wish you'd do lots more of them. One every hour would be about right.

They all have such nice voices!

@chrislongden4 The cosmological constant is denoted by the capital lambda (Λ), while the decay constant is denoted by the lowercase lambda (λ), which is used in the Half-life games.

What if the constant is like other forces in that it drops off exponentially? On the quantum scale it could be huge as the mechanics suggest, but on the cosmic scale it is small. That makes sense because when our universe is small it expanded the fastest then.

It is like saying," Am I big or small?" Well, it depends on your perspective. You can not define the constant because you are, because of it.

That is why Einstein came up with the cosmological constant, a hypothetical force to act as a repulsive constant in order to prevent the collapsing. The expanding models are not predicted by general relativity at all, they were proposed as ad hoc solutions by Alexander Friedmann. Look it up

@chrislongden4 the difference is upper vs lower case. In physics, lower case lambda can also be used for wave-lenght. It's also used in a lot of other fields, usualy refering to rates or distances.

another cracking episode!! iwant to be in a room with all the scientists for like a week it would be awesome!

@hikergate thank you... get our fair share of positive and negative comments, but always enjoy the positive ones more! ;)

I think these videos are excellent! If these are all professors at the uni of Nottingham, it makes me want to go back to school. ;)

@Philosification, I believe he considered it a mistake because if he hadn't introduced the constant his theory would have predicted that the universe must be constantly expanding. So that later, when Hubble showed that the universe was expanding, it would be another confirmation of relativity. By introducing the cosmological constant his theory becomes consistent with either an expanding, static, or contracting universe--making the theory appear more contrived than it actually is.

One of the most important things about a scientific theory is that it's falsifiable. No matter how beautiful the theory is or how long it has been standing. it can always been proved wrong. Like Feynman says: "If it disagrees with experiment, it's wrong!" Religion can't be proved, let alone that you can prove it wrong. Scientists may love their theories, they don't worship them.

Ok, but could the cosmological constant that quantum theory expects, actually be present and explained by Dark Energy?

i don't understand... we are talking about the cosmological constant...so in what sense is it constant? is it constant throughout the universe's space or throughout the universe's time... or both?

(cutting some corners) In Einstein's time the universe was assumed to be static. But gravity would ultimately attract all matter to each other, so that it would collapse onto itself. Which apparently didn't happen, so Einstein added the energy of the Cosmological Constant so that all matter would be pushed apart again to a state of equilibrium.

@anonysquirrel The Big Bang was not an explosion, that is a common fallacy. It was an expansion of space time, there is no momentum. The expansion is accelerating over time, not slowing. You'd expect it to slow to zero eventually if it were the result of an explosion. Lambda is a property of empty space, which is not "empty" but filled with quantum fluctuations of virtual particles.

@jgordon707, you don't come off as rude at all. I liken the cosmological constant to the interest rate on savings because they both only make sense as positive inflation rates and have many interesting shared corollaries. Both are measures of something somewhat intangible (the expansion of wealth is similar to the expansion of space--everywhere and uniform locally but not necessarily globally, etc.) And as I was trying to point out, both seem to have mysterious somewhat paradoxical properties.

Carmichael, i've been wondering the same thing about the plank length!

why it is applicable only among galaxies to move far from each other and why not among planets ???

If space itself is expanding then is the plank length getting larger? Is time speeding up or slowing down? and is the speed of light speeding up or slowing down?

My favorite symbol for 1 reason the Half Life series but these videos have actually given the symbol meaning thanks for all the videos

is the constant a very small amount of energy that just blankets the universe in all locations? Like Photons or something?

I think a lot of criticisms on this channel are invalid. Those who don't understand this, should first see the lecture by Lawrence Krauss: 'A Universe From Nothing' by Lawrence Krauss, AAI 2009 @05:55 After that this one should be a nice intermediate lecture. I think this one is just fine as it is.

Doesn't the quantum theory and the theory of relativity come together at the edge of a black hole? While the negative ions are absorbed into the black hole, the positive collect at the edge and are visible as light energy. Is that right? I think I read that somewhere. Not sure.

- "So what do you know?" - "I know calm down. Also my intelligent."

@OldSchoolSkill, I think our culture itself has rendered primary schools (both in form and content) virtually obsolete. It's simply not information that children can actually put to use--it grows ever more sterile and abstract. Even things like arithmetic are simply not skills we typically use much. I think we need a paradigm that creates a meaningful, productive, and financially rewarding role for children in society from the youngest ages possible. Demand driven education would be faster.

This made my day

To answer your Planck length question: if you further blow up a balloon 5 cm in diameter, do centimeters become larger as well?

@2szymi Not just you. Something strange going on there. The sound is odd too... I can't find a comfortable volume.

@OldSchoolSkill I'm sorry I meant to add a emoticon to the end of that comment to show that it was meant to be humerus. I was merely reflecting what I took to be the meaning of your comment back on you. "So a bunch of academics and lecturers failed to explain a hugely complicated and counter intuitive idea in a way everyone could understand in a 7 min video. That must mean they have an alterior motive!!!111 :-p" Or they could just be trying to do there best?

If they keep changing the value of the cosmological constant it's not very constant, is it?

ohh those videos don't have thumbs down.... that's quite awesome :D

nice explaination

I realize this is a philosophical question, and not a novel one at that, but allow me the curiosity to wonder if anyone might shed some light on this. If the cosmological constant is, as its name suggests, not contingent upon anything else, then could it be argued all contingencies arise from this non-contingent property?

So... if the expansion is accelerating then it couldn't have started from a 'big bang' unless im totally missing the understanding of the big bang theory? Im confused anyhow.

What would it mean if it was something like 1.0009 ?

@ananiasacts I hope this doesn't come off as rude, but that did little to help me understand the constant better. I missed the analogy part of it, if there was one. if you wanna talk about our money system thats cool I just dont see the connection.

I've heard it said that gravity is weak because it's leaking. Might this cosmological constant also be leaking in the same way? That way it can be a really big number, the same way gravity can be strong, but both have a small effect on what we can perceive? (:

What if a galaxy is going one direction at light speed and another is going the opposite direction at light speed. Relative to each other what would the red shift measure??

@OldSchoolSkill I'm an American and I understood this perfectly. Making broad generalizations like "most Americans would not understand this" only makes you sound ignorant and pretentious. Nobody wants help from someone so condescending. Although I agree that science should be made more accessible, I doubt many people come to this channel expecting accessibility; considering its dedicated to discussing some of the more complex theories in physics. Take your arguments to an introductory channel.

Fascinating!

Can you tell me where to find the picture used at 2:05 and 6:40? Those diffraction "pillars" look rather nice.

Did Einstein ever actually explain why he thought it was a mistake? He's never seemed the kind of person who would remove it without good reason. I'm assuming the guy who invented relativity didn't remove it for philosophical reasons.

@chrislongden4 I think thats the lower case lambda (also used to represent wavelength in optics), this video is talking about uppercase lambda. Right?

@Ibogaine306 neither, it was a command, to which everyone should follow.

@OldSchoolSkill "Most Americans" wouldn't understand this video? As opposed to whom? Most British people? Most German people? What are you even talking about? America is not actually as dumb as everyone seems to think. I found this video very clear and informative, and it (and other videos on this channel) are fantastic resources for the lay public with an interest in science. Who without an interest in science would watch these videos, anyway?

Is this cosmological constant describing dark energy?

ah I remember this from AS 102

@chrislongden4 its also used to represent a wavelength :)

Actually it is due to Galileo, he was the first to state the theory of relativity.

Can be your nerd roadie? i'd love to just go around to meet all of these wonderful scientists...

I'm a complete layman but given that scientist now believe that normal energy/matter makes up only 5% of the universe, with dark matter accounting for around 26% (which causes galaxies to spin faster than they should), and dark energy 69% (causing inflation), why would gravity ultimately attract all matter (presumably causing "deflation"?) when dark matter hadn't been postulated (as far as I recall), and gravity being the weakest force? Is it a case of cosmology revealing new problems?

@chrislongden4 isn't that the small letter lambda?

@NathBonn, like the pythagorean theorem? Or the theory of evolution by natural selection? They're both facts. There is every reason to treat them as such.

@OldSchoolSkill "Who pays for this series? What is their motive?" - A comment such as this is stock standard for a conspiracy theory/paranoid website/forum. In this light, I hope you can understand now how many might perceive this, even though u didnt mean it like that. Educating the web is a noble thought -i wish you luck! As you have discovered, Brady's channels have a fairly hardcore loyalist following, and most are just grateful for this rare, free, quality science on youtube. :)

@OldSchoolSkill, in Conrad Wolfram: Teaching kids real math with computers ( watch?v=60OVlfAUPJg ) he explains my perspective on math very well. I not advocating teaching them less, or how things are done--quite the reverse. I'm advocating (and trying to design myself) a meaningful role for them in local civics where children maintain the ontology used by their local government to represent its data in a sort of game. Effectively creating a map of their local economy which earns them income.

@oldschoolskill "students looking for science information on the Internet" Yep, I'm 15 and don't understand these videos. But it's still interesting. I'm scared of grade 11 physics. I don't know about the American school system, but I feel the Australian school system works great.

@jgordon707, I liken it to our banking system. If you analyze it one way, it doesn't make any sense--how can people pay interest on loans ff there is only a fixed amount of money in the world? Some people consider that proof that our money is genuinely meaningless and that we're ultimately due for a comeuppance because of that. Others feel that perspective itself is misguided and the premise is false. Money must be based on debt or it could not be used to make demands at all.

one of these guys sounds a bit like prof. brian cox, university of manchester?

@imalwayswatchingu00, It seems incongruous to be both scared of 11th grade physics and simultaneously enthusiastic about the quality of your school system. Did you mean in general? (Except for the fact that it makes physics look frightening?) You might enjoy Conrad Wolfram's TED talk about teaching mathematics. I suspect from the enormous popularity of the KhanAcademy on youtube, and talk's like Conrad's, that we're in the middle of a quiet revolution in the methodology of education.

Electromagnetic force is much much stronger, but its charge comes in two flavor. Over moderately long distance, the amount of positive and negative charges are roughly equal and their effect cancels each other. Gravity, though weak, is always accumulative. Over long distance, distance of planet, solar system, and galaxies, it becomes the only relevant force. The cosmological constant causes gravity to become repulsive at very long distance: on the order of the entire visible universe.

I wish i had the brain to comprehend physics, it is so interesting but with my grasp of mathetics impossible to understand the theory behind it :) il be ignornant in my ability to understand

Does this prove that the universe is finite?

Because it has to have the dimension of energy density

At the end of the video he says the cosmological constant may exist but that it's value might be zero. If it's value is constantly zero then why would you consider it's existence at all? Wouldn't that mean it didn't exist?

We are pixels trying to understand why the GPU does things. Simulation.

@xMadSkillzx That's lowercase lambda.

Could dark matter actually just be the mass that the cosmological constant induces in the universe?

tye speed of light is, ready? CONSTANT!!! O.o the speed at which time passes is not determined by expansion of the universe, but in fact by your velocity.

The guy in the glasses actually says "Science is all about aesthetics" as an argument against a small Lambda? Sorry dude, but science is about the data, not your personal sense of what is beautiful or pleasing.

@chrislongden4 lol-i imagine you now really regret asking that.Just read thru all the comments,after having to pause the vid,cause the flaming looked so interesting,and saw about a third of comments were all to you, and all telling you the same/similiar thing! I dont know what that phenomenon is all about - comment after comment after comment giving the same answers! What - can ppl not read anymore?! Just desperate to display that one nugget of knowledge? PS-the lamda symbol is used for... ;)

I've understood the purpose of humanity. Its to study physics.

@0:00 scared the fucking shit out of me..

i love sixty symbols :)

Why wouldn't the Cosmological Constant be the speed of light?

Yeah, right. Except that LHS has the dimension of energy, while RHS has the dimension of mass. There's an equivalence between mass and energy, but they're not the same. You don't say 1 kg = 1 m either.

is it only me or the fps are low?

You would be wise to look and then open your mouth and use your real name as you see done on Natures site. It only requires 7th grade math skills to see CERN's v-c/c=2.48e-5 in 453.6m matches SLAC's E158 data on the asymmetry of the weak force creating a .20e-5 harmonic comma, but if you read my first post you will see I said it should be closer to 2.30 and CERN later changed it to 2.37e-5. I said the Comma was too big. However your attitude shows this is far beyond your understanding.

the speed of light is also a constant ;-)

No, it's true. Ptolemy's model for the planets' orbits looked horrible, with epicycles upon epicycles. It was too much tinkering, it simply had to be wrong. And it is. Enter Kepler and now the orbits become nice and simple ellipses. Newton invented the maths to prove it. And for everyday use (ignoring general relativity, see Mercury's precession) it still holds.

lambda (as a word, not a symbol) is also used in programming but seems to be completely irrelevant to the way it is used in this video haha

It's shaky because of his excitement

In layman's terms "we don't know"

I try to combine the cosmological constant and the schrodinger solution on the planck scale. I used planck units. At the end I went back to SI units to compare with the measured vacuum energy density (0.63 10^-9 J/m^3.) Combine: 1) Einstein, cosmological constant 2) Schrödinger solution 3) Planck units Result: - vacuum catastrophe solved? 1)Einstein, cosmological constant Λ = (8π 𝐺 ƐΛ)/(𝑐^4) Planck units: G=1 c=1 Λ (6.1871424 10^34)^-2 = (8π ƐΛ [planckEnergy/planckVolume] 1.1056 10^-52 (6.1871424 10^34)^-2 = 8π ƐΛ 0.001149 10^-120 = ƐΛ 0.1149 10^-122/ ƐΛ = 1 2)Schrödinger solution, n=1 (ℎbar^2 𝑛^2 𝜋^2) / (2𝑚𝐿^2) = E Planck units hbar=1 n=1 m= mplanck =1 L= Lplanck=1 0.5 𝜋^2= E 1= E/0.5 𝜋^2 3)Einstein, Cosmological Constant = Schrödinger solution 0.1149 10^-122/ ƐΛ = 1 = E/0.5 𝜋^2 0.1149 10^-122 0.5 𝜋^2= ƐΛ Eplanck Eplanck =1 0.1149 10^-122 0.5 𝜋^2= ƐΛ 0.567 10^-122 = ƐΛ [planckEnergy/planckVolume] 0.567 10^-122 1.9561 10^9 /(1.61625502 10^-35)^3= ƐΛ [J/m^3] ƐΛ = 2.627 10^-9 [J/m^3] Measured: 0.63 10^-9 [J/m^3] I am looking forward to your response.

@OldSchoolSkill There is other shows and books that try explain everything from the ground, like latest Stephen Hawking book, I actually did not liked latest book exactly because it spend way to much time explaining basics - I'd rather watch something for more educated people. Yeah there are a lot of people without normal scientific education, but that's not our problem is it?

They can't move at light speed; their mass would become infinite.

Let's say you devise a scientific theory, but when you do your calculations they end up as 6 = 5 So there must be something not right. What Einstein essentially did was change it to 6 = 5 + 1 just by adding the "+ 1" term. The "+ 1" is the cosmological constant. It fixed the equation, but there was absolutely no explanation for it.

@OldSchoolSkill is there any particular reason why you say americans wouldn't understand it? if you look at those statistical graphs on previous nottingham videos, you'll see the US is about the 2nd highest in most views, so clearly americans understand. if you're basing your idea on educational stats, keep in mind that the US includes EVERYBODY, including the mentally incapable. other countries deliberately only keep track of people who actually graduated or are currently going to school.

The universe is evolving into what

So Einstein makes his 'biggest mistake', by predicting Lambda, but then I hear you guys explain it still probably has some value. So what effect does it have to our universe, as compared to having the value of Lambda equal to 0?

The video is kinda laggy

@OldSchoolSkill Nahhh! Let it blow over! In the mean time, on web, check out 'skeptoid' by Brian Dunning - imo best science/critical thinking podcast on web! (if u havent already) And great forums with lively debates. Prob the best thing anyone could have done for me as a kid would have been teaching me how to think critically and scientifically. and u can make all the suggestions there u want! Go there and do yr kids a favour!!! :)

Question: Why Pi (π) is used in the calculation of the cosmological constant? What is wrong with that naughty number, why is it used everywhere? Is it because physicists are just lazy?

λ bλows my mind away..

"Einstein's original model had the universe expanding" Sorry but that is utterly false. According to Einstein's original model the universe should COLLAPSE (not expand) because gravity should induce it to collapse under its own weight, that is, mutual attractions would cause all galaxies or large assemblies to be pulled toward one another, since they had insufficient velocity to resist the attraction.