Do electrons move at Absolute Zero?

so if we consider with my with my little set of atoms gone where my atoms go oh all right if at Absolute Zero all movement stops does that include the orbit of electrons around the nucleus of an atom no that's a really really good question because that embodies I would argue at least three modules worth lecture modules worth of material to address that that's a fantastic question you're not going to take three modules right I might first of all at the absolute zero of temperature you can't get there but even if you could and people can get down to very very low temperatures the electrons are still whizzing around there are fluctuations in particles and there some are caused by thermal excitations that the temperature that you've just talked about and some are just intrinsically quantum mechanical they're just there in the system and so even if you call the system to absolute zero which you can't but if you could then they'd still be the quantum fluctuations and I think therefore they would could still be effectively orbits around an atom first of all you can't reach absolute zero and you can look at that two ways you can look at that actually put aside all the quantum mechanics stuff and let's just look at the thermodynamics that was done centuries ago something called the third law of thermodynamics loosely stated and I don't want to raise the ire of all the professional physicists that loosely stated what the third law tells us is that you can never in a finite number of steps you can never reach Absolute Zero at high temperatures the atoms are vibrating quite strongly about their equilibrium positions these we can regard these little bonds as being like Springs and so the atoms are vibrating and then as we cool down these vibrations get less and less and less but even as we approach absolute zero we can never get rid of the zero point energy motion so the atoms will still have this zero point energy motion associated with with quantum mechanics at the quantum mechanical level we have the Heisenberg uncertainty principle the Heisenberg uncertainty principle tells us we can never precisely know the position of something because of we know precisely the position of an electron then we have a huge uncertainty in its momentum and also huge uncertainty in its energy which means it could in principle how much you know were very very large energy according to quantum mechanics again using Heisenberg's uncertainty principle electrons are confined in a small space in the atom so-called Bohr radius which is about 10 to the minus 10 meters and again according to the laws of quantum mechanics if they confined in that space they have strongly confined and therefore there's an uncertainty in the momentum and velocity so they certainly aren't at rest even at Absolute Zero quantum mechanically you still have vibration because you have a small amount of uncertainty about where the position of an electron or nucleus or an atom is if the universe is expanding slower than the speed of light why hasn't the light from the Big Bang already passed us you shouldn't it's a mistake to think of the Big Bang happening at a particular place the Big Bang happened everywhere it's just at the time everywhere was very close together and since then everywhere has been flying apart from everywhere else but of course we were kind of in the middle of the Big Bang when it happened because we wanted part of that everywhere and so the explosion the light that that explosion created was all around us then and it streamed away from us but bits of the explosion that were not where we are has been traveling towards us and some of that's arrived some of that's already passed us the Big Bang is isn't isn't at a fixed point in the in space if you like it's not that it happened there and it didn't happen everywhere else space and time are created from the Big Bang so if you like as the universe is expanding it's always got a remnant of the Big Bang in it and we can actually see it it's this thing called the Cosmic Microwave Background the Cosmic Microwave Background is a very weak source of light it's very wimpy sort of radio waves because the explosion is cooled down a lot just because of the expansion of the universe but we could still detect it and in fact you can see it for yourself if you turn on your television and it's not tuned to any particular channel so you just see that fuzz on the screen about 1% of the little fuzz that you see there the apparent noise is actually you your television detecting cosmic microwave background photons so you can actually see the light from the Big Bang yourself this is the beauty of looking out in astronomy what we're not only looking out at distances we're looking back in time and so you one way of thinking about this if you if you imagine we're at the center of a big sphere and the surface of that sphere is is that blanket of radiation and it's just propagating to us and it's propagating from all directions so now you can see that whichever direction you look you're going to be able to see some remnants of this radiation it I mean it does interact with each other and it in some sense it does go past us but it's also coming from other directions that one of the most amazing things about this radiation of course is that it's so uniform it's so come almost completely uniform in temperature that's showing that the universe is what is called isotropic it looks the same in all directions if I look out that direction far enough and look out in that direction far enough and can measure the temperature of the radiation coming back towards me it's it's almost the same it's the differences between that radiation once you've taken out certain effects like the fact that we're moving through the Milky Way and stuff like that once you once you take those out those differences in those temperatures is is is only about 10 to the minus 4 degrees Kelvin are you good at sport well I love playing cricket doc Patek but I always loved bowling when I was a kid I wasn't very good but I did I did enjoy a lot of fun out of that yeah making batsmen hurry a little bit but I was never very good at it but a great fun I used to be I used to be no absolutely not woefully bad terrible well I think I enjoy sports certainly I play football with all the boys and enjoy myself and they haven't kicked me out yet so I guess that's okay I try is I guess this your answer I mean over the years I've done various books I used to do quite a lot of Judo used to be a goalkeeper for a five-a-side football team he used to play football at my college as a goalkeeper I got this this was kicked in by one of my defenders so this Hyosung can rotated round I actually think physical exercise is bad for you you keep away from look at all the damage that's done with physical exercise with sports just keep away from it if we didn't do it we'd much healthier I used to play five-a-side football and I got an e-value John still because I ruptured the ligaments in my knee but unfortunately sooner or later it caught up with me and I ended up falling awkwardly and tearing all bunchy ligaments which kind of point in to it and I get it's for it I used to be I used to be a rower and I used to be a runner and I'm trying to become one again so yeah I like sport so when nature tells you that you really can't walk around without a bandage you give up the sports I I love sport and I would like to think I'm really good at it but I'm not good enough to have ever I played at school and I played at University and I represented my local town it's swimming and I had trials for Yorkshire cricket so I was alright and but I never I never made it to the full level of a professional in or anywhere near as good I would have loved to have been but no my father we lived in Wembley my father bought two tickets for the World Cup in 90 66 and he would go with either me or my brother-in-law Ian and as it turns out as my brother-in-law reminds me Ian didn't go to the Cup final I did so I saw England win the World Cup you

Channel: Sixty Symbols

Views: 1,035,610

Rating: 4.9227152 out of 5

Keywords: electrons, big, bang

Id: Oba_RxdESSs

Length: 8min 25sec (505 seconds)

Published: Thu Nov 04 2010