Skip to comments.Physicists create a 'perfect' way to study the Big Bang
Posted on 07/22/2005 4:15:47 AM PDT by PatrickHenry
Physicists have created the state of matter thought to have filled the Universe just a few microseconds after the big bang and found it to be different from what they were expecting. Instead of a gas, it is more like a liquid. Understanding why it is a liquid should take physicists a step closer to explaining the earliest moments of our Universe.
Not just any old liquid, either. Its collective movement is rather like the way a school of fish swims 'as one' and is a sign that the fluid possesses an extremely low viscosity, making it what physicists call a perfect fluid. In fact, tentative calculations suggest its extraordinarily low viscosity makes it the most perfect fluid ever created.
Researchers had confidently believed it would be something like 'steam', consisting of free quarks and gluons. "No one predicted that it would be a liquid," said Professor John Nelson from the University of Birmingham, who heads the British involvement in the STAR Collaboration, a multinational experiment. "This aspect was totally unexpected," said Professor Nelson, "and will lead to new scientific research regarding the properties of matter at extremes of temperature and density, previously inaccessible in a laboratory."
The Birmingham contingent is funded entirely by the Engineering and Physical Sciences Research Council (EPSRC).
The new state of matter was forged in the Relativistic Heavy Ion Collider (RHIC), situated at the Brookhaven National Laboratory, Long Island, New York. By colliding the central cores of gold atoms together, head-on at almost the speed of light, the researchers created a fleeting, microscopic version of the Universe a few microseconds after the Big Bang. This included achieving a temperature of several million million degrees (about 150,000 times the temperature at the centre of the Sun). They then detected the rush of particles that this miniature 'big bang' created. That was when things started to take an unexpected turn.
Instead of the 'every-particle-for-itself, free-for-all' that is expected from a gas, the researchers saw evidence of collective movement as the hot matter, formed at RHIC, flowed out of the collision site. This indicated stronger interactions between the particles than expected, leading to the belief that the quark-gluon plasma is behaving like a liquid.
This type of experiment furthers our understanding of what happened in the instants immediately following the Big Bang, leading to a better understanding of the earliest moments of the Universe. However, the unexpected nature of this new state of matter is leaving physicists wondering if the current theoretical models can support these surprising new experimental results.
The early Universe is thought to have been a place of extraordinarily high temperatures and energies. Matter as we know it could not exist under those conditions. Rather like an ice cube placed in a hot oven, atoms dissolve into a new state of matter consisting of minuscule particles, the most significant of which are known as quarks and gluons.
For over twenty years, physicists have been searching for the quark-gluon plasma, because of the insights it can give into the earliest moments of the Universe and the structure of matter. However, this latest development is much more unusual than anyone expected.
There is a suggestion that certain versions of string theory may be able to explain the 'liquid' behaviour of the quark-gluon plasma. Professor Nelson expects that progress will be made during the forthcoming Quark Matter 2005 conference in Budapest in August. "Although these findings did not fit with expectations, the theories are slowly coming into line. Hearing the theoretical developments is going to be the high point of the conference," said Professor Nelson.
EPSRC (under its previous name of SERC) was the first British research council to fund heavy ion collision experiments. Starting in the mid 1980s, they made it possible for British nuclear physicists from Birmingham to participate in such experiments at CERN (the European Centre for Nuclear Research).
Professor John Nelson heads an EPSRC-funded research group of five staff members and four PhD students at the University of Birmingham, UK. Together they contribute to the STAR experiment running on RHIC.
STAR is one of four particle detection experiments running at RHIC. The name is an acronym for Solenoidal Tracker At RHIC. The experimental apparatus wraps itself around the collision site and tracks the particles given off, providing the information necessary for physicists to determine the nature of each particle produced in the collision.
STAR is one of four complementary experiments running at RHIC. The other three are BRAHMS, PHENIX and PHOBOS. All four experiments corroborate the nature of the quark-gluon plasma found at RHIC.
Hmm.. Sounds more like a Big Burble!
I beg to differ..
There was speculation that while creating the quark gluon plasma a byproduct of the process would be the creation of a small black hole.
They're going to study the big bang? I don't know if i can perform with scientists watching me an the ol' lady!
I didn't understand why colliding gold atoms would create a big bang like situation.
In the Beginning G-D CREATED the heavens and the Earth... Gen 1:1A, any questions? CAN YOU HEAR ME NOW!!
They use Gold partially because it doesn't react with anything - they know that there will no peturbations from Gold Oxide contaminants for instance.
They don't use a whole lot of Gold, if you're worried :0)
Sorry only partially answered your question: Gold is used as a collision target somewhat the reason I gave, but as to why they would expect a BB situation - well they carry out High Energy collisions for any and every experiment in Particle Physics. The actual metals they use in targets is not that important (as long as you avoid contamination).
certain versions of string theory
If you get enough versions, at some time one will fit. The jury is still out on string theory. It is sort of like long term weather and stock market programs. They need a little tweak, after the fact, to explain what happened. Unfortunately they do not consistently explain what will happen, but there are so many around that occasionally one of them does, short term.
Another problem is the leap of faith that because the experiment yielded certain results, they can be extrapolated into what happened just after the big bang. Maybe yes, maybe no.
Good observations, however, and interesting, but I would not leap that far right now.
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?
No, its a pale dry ale!
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 the ping!
"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.