Thanks for your reply. I do know that gold is inert - but how does making inert substances collide at super high speeds simulate the big bang? What we know of the big bang arises from observations after the event. We don't know what conditions led to that event arising, do we? Therefore, isn't this experiment artificial, in more ways than one?
I'll venture a guess: at the pressures and temperatures that are achieved after impact, one no longer has "gold", but merely, protons, neutrons, electrons, other elementary particles, light, energy, etc.
"Thanks for your reply. I do know that gold is inert - but how does making inert substances collide at super high speeds simulate the big bang? What we know of the big bang arises from observations after the event. We don't know what conditions led to that event arising, do we? Therefore, isn't this experiment artificial, in more ways than one?"
They use gold simply because it is a relatively heavy nucleus (therefore it has more kinetic energy at close to "c") and is condusive to being easily accelerated to those unbeleivable velocites for technical reasons not all of which are known to me.
It doesn't matter so much that it is gold, but that it is matter in general, being collided with other matter with very high energy.
It does relate to the big bang in a way. We can see plainly now that the universe is expanding, that everything in the universe, on a large scale, is moving apart from everything else at ever increasing velocity. Therefore we can extrapolate back that, since everything is moving apart from everything else, at some time in the past it would have been much closeer and packed together in s small space.
We can see how much matter there is, for the most part, and we are starting to get a good understand of how matter behaves and would behave under a variety of conditions and at different energies.
When you are trying to simulate extremely hot, dense, and energetic matter, the best way to do that would be to squeeeeeze as much matter as you can into a small space with very high energy. The way particle physicists can do that is what accelerators which will knock atomic nuclei together so hard, that much of the kinetic energy itself turns into mass, creating a very hot, dense soup of exotic particles, (no longer resembling whatever substance was originally collided in any way, shape or form) which then will immediately decay as much of the mass created relinquishes it's energy. All of this can be detected.
At the velocities under which the gold atoms collide, so much heat and pressure are created that the gold nuclei no longer exist. The gold atoms essentially 'melt' into their constituent particles. It so hot and the pressures are so high that even the protons and neutrons are 'melted' into their constituent particles, quarks and gluons. The conditions necessary for this to happen occurred shortly after the Big Bang. This experiment give a glimpse as to what condition matter was in under those conditions and how it behaved. It is opening a door into experimental work at temperatures and pressures so extreme that they have never been directly observed before.