Do We Finally Know Why We Exist?

hey 42 here in 333 bc alexander the great led his army into the phrygian capital of gordium in modern-day turkey where as the story goes he found an ancient wagon the yolk of the wagon was secured with a nest of knots so intricate it was impossible to see how the rope was tied together legend had it the wagon had belonged to gordius the father of king midas and according to an oracle whoever was able to undo the massive knots would become the ruler of all asia since conquering the known world was quite high up on alexander's to-do list he immediately had a go at unravelling the ropes but with no success after muttering a few macedonian expletives the young king took a step back and looked at the problem from a different angle it occurred to him that it didn't matter how the knot was untied just that it was broken so he took out his sword and sliced a knot in half just the sort of thing you'd expect from someone whose surname is the great alexander would go on to prove the oracle right by building an empire that stretched across three continents and covered around 2 million square miles whilst the gordian knot became a symbol for seemingly unsolvable problems that require a fresh insight to decode we have more than a few gordian knots around these days like how do we stop climate change what do we do if we run out of water and how do we integrate the standard model of particle physics with the theory of general relativity okay that last one probably isn't the top of your mind whilst you're munching on your breakfast cereal or swiping right on tinder but it keeps physicists awake at night because unless we answer this question we may never understand the nature of reality the problem is this modern physics is based on two major systems that don't agree with each other the theory of general relativity helps us understand the really big stuff like planets stars galaxies and kanye west's ego whilst quantum mechanics helps us understand all the really small stuff like molecules atoms and the subatomic world both these theories are extremely successful which in scientific terms means they consistently make accurate predictions not that they drive ferraris and have deepak chopra on speed dial independently these theories have revealed the nature of space and the basic structure of mata but when we try to combine them things get awkward for the last 50 years scientists have managed to ignore the cosmic elephant in the room but certain questions keep coming up which have highlighted the conflict between quantum mechanics and general relativity at the center of a black hole for example extreme gravity means massive amounts of matter are crushed to a minuscule size and at the moment of the big bang the whole universe erupted from a microscopic particle in both these examples the insanely big and the insanely small are present at the same time so we need a set of rules that explains what happens in those scenarios but neither general relativity nor quantum mechanics alone are able to do that this is the central problem of modern physics which is why for more than 100 years scientists have been searching for an ultimate theory a master theory a theory of everything that could explain well everything this would be the sword that slices through the gordian knot and there are currently a few different candidates for a theory of everything but more on that later first we need to understand how we got ourselves in this mess in the first place and to do that we need to get our heads around force no not the time yoda uses to lift women's skirts we're talking about the four fundamental forces of nature gravity electromagnetism the weak nuclear force and the strong nuclear force as anyone with half an hour's worth of gum wrapper education could tell you the force of gravity was discovered by sir isaac newton a scientific genius who also established the laws of motion and a whole new branch of mathematics you know and love as calculus or at least a modern version of it though newton only shared the story much later in life the legend of how he came upon the law of gravity began in 1665 with him sitting in deep fort in his garden ordinarily he would have been attending lectures at the university of cambridge but the school was closed and the students were sent home due to a national outbreak of the bubonic plague sound familiar newton preferred to rely on observation and testing over theory this was a guy who when studying optics stuck a blunt needle in his eye to see what happened instead of trusting the textbooks of the time like i said the genius so when he saw an apple fall from a tree in his garden he forgot theory and came up with a brand new perspective on what had caused the apple to drop gravity is such a basic part of our lives that it's hard to imagine a time when our species had no real clue how it worked but back when newton first began developing his ideas some theologians still believed planets moved due to the beating of angels wings and scientific theory was still largely based on the work of ancient greek philosophers from thousands of years before it wasn't even called science yet what newton studied was known as natural philosophy at the time newton's professors were still teaching aristotle's view of the world which was that some substances like apples had a quality called gravity which made them full whilst others like smoke had a quality called levity which made them rise newton realized gravity is a force that pulls things down to earth but his law of universal gravitation went further to say that gravity acts on all objects including planets newton was the first person to understand why planets stayed in orbit and how the force that kept the earth circling the sun was the same one that made apples fall from trees in modern scientific language newton unified celestial and terrestrial gravity instead of two separate explanations for two effects both could now be explained by one complete theory a theory of everything would have the same goal but on steroids unification was also behind the discovery of the second major force electromagnetism by the late 19th century electricity and magnetism had been known for millennia magnets occur naturally in the form of magnetite and lodestone whilst electricity is all around us just think of lightning or electric eels by the late 1800s a few studies have been published showing a connection between electricity and magnetism but they were always considered separate phenomena it wasn't until james clark maxwell published his list of differential equations imaginatively called maxwell's equations that we understood electricity and magnetism to be different expressions of one electromagnetic force the final two forces we would need to include in a theory of everything are the weak and strong nuclear forces which were only discovered fairly recently the strong force was identified in 1973 and there which was predicted in the 60s the weak force was only confirmed in 1983 but before we dive into those forces a quick word on subatomic particles the ancient greeks believed the world was composed of fundamental building blocks of reality called atoms a name which came from the greek term atomos which means indivisible these were thought to be unbreakable pieces of matter so small they couldn't be seen like microscopic lego that connected in different ways to create the objects we see around us like so many ancient greek predictions this turned out to be amazingly close to the truth researchers in the 19th century proved that common substances like oxygen and carbon were made of smaller units which as a nod to the guys in togas they called atoms by the early 20th century though it was clear atoms were made up of even smaller components called protons neutrons and electrons and in 1913 the world was introduced to the solar system model of the atom that we know so well today but as technology has evolved and our ability to analyze the subatomic world has improved even smaller components of reality have been discovered in the 1930s physicists discovered the muon similar to an electron but about 200 times heavier in the 50s conclusive evidence was found for the existence of the neutrino an invisible particle that moves through mata like it doesn't matter i did a whole video on those mysterious little buggers recently then in 1968 researchers at the stanford linear accelerator center found that protons and neutrons aren't even fundamental turns out they're made up of even smaller particles called quarks so far as we can tell quarks truly are fundamental and can't be further divided and they may not even have size at all as they're too small for us to measure even with our highest resolving equipment but then again we used to think that's about atoms too so you never know it may be that as technology keeps improving we'll be able to keep zooming further and further into subatomic particles and who knows what we may find perhaps at the heart of all reality there's a tiny old lady making mata out of pancake batter in a matter of decades physicists have identified hundreds of different subatomic particles with names like lepton tau and other words you might hear at a star wars convention physicists needed some way to make sense of it all and so emerged the standard model of particle physics the standard model is considered by many to be the most successful theory ever devised and it provides a solid framework for understanding and predicting the behavior of particles in the subatomic world naturally without some kind of force these particles will be moving around chaotically so physical forms including you and i would shift and change constantly i find it hard enough to keep my [ __ ] together as it is fortunately for us all there are at least three forces maintaining order in the quantum universe we've already met the electromagnetic force that amongst other things keeps electrons obediently orbiting the nuclei of atoms the weak force is responsible for particle decay which is when one subatomic particle like a proton or an electron decides it would like to change into a bunch of other subatomic particles for no apparent reason without the weak force we wouldn't have the nuclear fusion reactions that power the sun and produce the energy needed for life on earth so it's fairly important the strong force binds quarks in clusters that make up subatomic particles like protons and neutrons and also holds together the atomic nucleus itself if someone at a subatomic cocktail party were to ask the strong force what it does for a living it would say something like i'm responsible for the underlying stability of all matter then it would down a bottle of tequila and ride away on a unicorn made of fire unlike gravity and the electromagnetic force which can operate across great distances the strong force and the weak force only work over incredibly short distances we're talking just a couple of fentometers at the very most how big is a femtometer about the size of a proton so yeah pretty damn small perhaps unsurprisingly the strong force is the strongest of forces followed by the electromagnetic force which is a hundred times weaker and then the weak force which is one hundred thousand times weaker the strong force is six thousand trillion trillion trillion times stronger than gravity which in the world of forces is a total wimp gravity doesn't even show up at a quantum level so it's not included in the standard model of particle physics and so we arrive back at our original problem the conflict between classical physics which is based on gravity and quantum physics which is based on the other three forces things first went awry in the late 1800s when it was realized newton's laws of motion and james clark maxwell's laws of electromagnetism contradicted each other particularly when it came to light according to newton you could catch up to a beam of light if you ran fast enough according to maxwell you couldn't this disagreement was eventually resolved by albert einstein whose theory of special relativity proved that space and time are relative not fixed as people had always believed quite a few physicists needed a stiff drink after that one unfortunately einstein's genius was about to bite back because the development of the special theory of relativity set up a new inconsistency this time with newton's well-tested universal theory of gravitation einstein's work concluded that nothing could travel faster than the speed of light but newton's calculations suggested gravity operated across vast distances of space instantly clever clocks that he was uncle albert fixed that issue too using a new and improved notion of gravity he detailed in his 1915 creation the general theory of relativity this hypothesis suggested space and time are warped and curved by matter and energy and these changes to the space-time landscape are responsible for what we experience as gravity which isn't actually a force at all but once again in solving one problem einstein had only highlighted another in the early 20th century physicists including einstein himself began developing the field of quantum mechanics and it soon became clear that gravity and the theory of general relativity didn't apply at the quantum level at the same time electromagnetism which was the only other force known at the time couldn't explain the many mysteries of the cosmos on its own einstein became obsessed with the problem and spent the next 30 years searching for what he called a unified field theory a framework that could explain all the physics from the macro to the micro but as you've probably worked out by now einstein never succeeded and nor has anyone else today there are a few candidates for a theory of everything that might unify the free forces of quantum physics with the gravitational force of classical physics but for now they're just that theories there's been little or no evidence of these working in experiments so we definitely can't declare any of them to be true perhaps the most promising pretender to the crown is string theory this mathematical model proposes all the different subatomic particles known to science are not particles at all but rather hypothetical strings that vibrate in different ways according to this theory the vibration of a string amongst other things determines whether it will show up as a proton or a quark or something else entirely for this model to work the universe needs to have many more dimensions than the three or possibly four if you want to get all fancy and include time that we're familiar with most likely 10 whilst the strings themselves need to be one dimensional so they only have length no width or height don't try to imagine it seriously your brain will explode just like rocky movies there seemed to be a never-ending stream of new string theories so in the late 20th century scientists gathered the five string theories that existed at the time under a more general framework called m theory which presumably just to one up the other string theories requires 11 dimensions weirdly nobody really knows what the m in m theory stands for the best guess is membrane but apparently it might also be master matrix mother magic or monster clearly nobody has the faintest idea so i'm going to assume it stands for mango at the moment the only real rival to mango theory is something called loop quantum gravity the basic idea is that the universe is not continuous like we think it is but rather a series of absurdly small chunks linked together where these links get twisted or braided particles form like string theory there is no experimental proof this theory might actually work and probably more concerning nobody's found a way to incorporate gravity so as a theory of everything it might be a bit useless other theories include quantum einstein gravity quantum gravity internal relativity and e8 an 8-dimensional mathematical pattern with 248 points that can be used to map the fundamental forces and particles of known physics to understand what those guys have been eating watch my recent video about magic mushrooms none of these approaches has had enough research and support to be tested as a true theory of everything so it seems we're still pretty far off but what does that matter would anything in your life change if you suddenly understood the ultimate theory probably not still it would be kind of nice to be able to say we've defeated the final boss and completed physics you know just to show off thanks for watching you can now buy my new book stick a flag in it on amazon or get the audio book on audible you'll find a link to both in the description below thank you

Channel: Thoughty2

Views: 985,013

Rating: 4.8994565 out of 5

Keywords: theory of everything, relativity, quantum, mechanics, science

Id: XijssbYdD9M

Length: 18min 55sec (1135 seconds)

Published: Fri Jan 22 2021