https://www.ted.com/talks/rolf_landua_what_happened_to_antimatter/transcript?language=en#t-6684
"Is it possible to create something out of nothing?Or, more precisely, can energy be made into matter?Yes, but only when it comes togetherwith its twin, antimatter.And there's something pretty mysterious about antimatter:there's way less of it out there than there should be.Let's start with the most famous physics formula ever:E equals m c squared.It basically says that mass is concentrated energy,and mass and energy are exchangeable,like two currencies with a huge exchange rate.90 trillion Joules of energyare equivalent to 1 gram of mass.But how do I actually transform energy into matter?The magic word is <i>energy density</i>.If you concentrate a huge amountof energy in a tiny space,new particles will come into existence.If we look closer,we see that these particles always come in pairs,like twins.That's because particles always have a counterpart,an antiparticle,and these are always producedin exactly equal amounts: 50/50.This might sound like science fiction,but it's the daily life of particle accelerators.In the collisions between two protonsat CERN's Large Hadron Collider,billions of particles and antiparticlesare produced every second.Consider, for example, the electron.It has a very small mass and negative electric charge.It's antiparticle, the positron,has exactly the same mass,but a positive electric charge.But, apart from the opposite charges,both particles are identical and perfectly stable.And the same is true for their heavy cousins,the proton and the antiproton.Therefore, scientists are convincedthat a world made of antimatterwould look, feel, and smell just like our world.In this antiworld,we may find antiwater,antigold,and, for example,an antimarble.Now imagine that a marble and an antimarbleare brought together.These two apparently solid objectswould completely disappearinto a big flash of energy,equivalent to an atomic bomb.Because combining matter and antimatterwould create so much energy,science fiction is full of ideasabout harnessing the energy stored in antimatter,for example, to fuel spaceships like Star Trek.After all, the energy content of antimatteris a billion times higher than conventional fuel.The energy of one gram of antimatter would be enoughfor driving a car 1,000 times around the Earth,or to bring the space shuttle into orbit.So why don't we use antimatter for energy production?Well, antimatter isn't just sitting around,ready for us to harvest.We have to make antimatterbefore we can combust antimatter,and it takes a billion times more energyto make antimatterthan you get back.But, what if there was some antimatter in outer spaceand we could dig it out one dayfrom an antiplanet somewhere.A few decades ago, many scientists believedthat this could actually be possible.Today, observations have shownthat there is no significant amount of antimatteranywhere in the visible universe,which is weird because, like we said before,there should be just as much antimatteras there is matter in the universe.Since antiparticles and particlesshould exist in equal numbers,this missing antimatter?Now that is a real mystery.To understand what might be happening,we must go back to the Big Bang.In the instant the universe was created,a huge amount of energy was transformed into mass,and our initial universe containedequal amounts of matter and antimatter.But just a second later,most matter and all of the antimatterhad destroyed one another,producing an enormous amount of radiationthat can still be observed today.Just about 100 millionthsof the original amount of matter stuck aroundand no antimatter whatsoever."Now, wait!" you might say,"Why did all the antimatter disappearand only matter was left?"It seems that we were somehow luckythat a tiny asymmetry existsbetween matter and antimatter.Otherwise, there would be no particles at allanywhere in the universeand also no human beings.But what causes this asymmetry?Experiments at CERN are trying to find out the reasonwhy something existsand why we don't live in a universefilled with radiation only?But, so far, we just don't know the answer."