CERN Accelerating science

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Back in time to the Big Bang

Ellen ( Teen-age girl scientist)
So, Tim - do you find the atom interesting?
Tim (Teen-age boy) Great! It's fascinating that everything is made of just three particles - electron, proton, and neutron.
Ellen Did you know that protons and electrons are immortal - well, we know that both live much longer than the age of the Universe.
Tim So my body is made of particles that will never die? How old are these particles?
Ellen About 15 billion years � the same as our Universe.
Tim Wow! I don't feel that old � But: how were these particles made?
Ellen They were created from energy in the first instants after the Big Bang. Remember your training course?
Tim Yes, E = mc2 - mass is concentrated energy. But I also learned that particles and antiparticles are always created together. So there must be the same amount of antiparticles around. Where is all this antimatter?
Ellen You're right - at the very beginning, there must have been equal amounts of particles and antiparticles. But somehow, the Universe became 'lopsided' during the first instants - and matter won the fight against antimatter.
Tim That sounds interesting. Can you explain that a little slower?
Ellen OK, let's take a trip back to the Big Bang in my time machine!

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