Wednesday, September 10, 2008

large hadron collider

image courtesy fractal world gallery.

today the most powerful physics experiment ever built, the large hadron collider will re-create the conditions (as scientists understand them) just after the big bang in an attempt to answer some long-standing questions about the universe. filling a massive tunnel under switzerland and with a circumference of 26 659 m, the statistics describing the lhc accelerator boggle not only the lay mind but that of even the most high-end out-there quantum physicist.
consider the following incredible factoids:

-there are 9,399 magnets cooling the machine.

-just one-eighth of its cryogenic distribution system would qualify as the world’s largest fridge. all the magnets will be pre‑cooled to minus 193.2°C (80 K) using 10 080 tonnes of liquid nitrogen, before they are filled with nearly 60 tonnes of liquid helium to bring them down to -271.3°C (1.9 K).

-at full power, trillions of protons will race around the lhc accelerator ring 11 245 times a second, travelling at 99.99% the speed of light.

-altogether some 600 million collisions will take place every second.

-to avoid colliding with gas molecules inside the accelerator, the beams of particles travel in an ultra-high vacuum – a cavity as empty as interplanetary space. the internal pressure of the lhc is ten times less than the pressure on the moon!

-when two beams of protons collide, they will generate temperatures more than 100 000 times hotter than the heart of the sun, concentrated within a minuscule space.

-the lhc's detectors have sophisticated electronic trigger systems that precisely measure the passage time of a particle to accuracies in the region of a few billionths of a second. the trigger system also registers the location of the particles to millionths of a metre.

-the data recorded by each of the big experiments at the lhc will fill around 100 000 dual layer dvds every year.
for more detailed stats this should answer any questions you might have!

this incredible project had its beginnings back in the 1980’s when it was first thrown out as an idea at a symposium where “what-ifs” were tossed about and working groups were delegated to determine what could be potentially discovered through the development of such a machine. from that point, theoretical and practical discussions and experiments were conducted to establish and assess the feasibility of some of the technology required. approval of the project as it was initially conceived was arrived at in 1994. to view a more detailed overview of this process, you can see the answers to a few unanswered questions, and for more information regarding the stages of this project chronologically, if you visit here you can see a detailed timeline.


i am not a particle physicist, although i will tell you that the whole world of quantum physics has been of interest to me since reading works some twenty five years ago by david bohm and gary zukav (notably "the dancing wu li masters") both of whom drew heavily on their respective degrees of expertise in this area. the people at c.e.r.n. have posted an excellent and accessible piece into the workings of the lhc here.

now for me this is where the whole thing gets interesting. c.e.r.n. has tucked inside its website a page devoted to what are termed "secret dimensions". this is very appealing of course, because anyone who is at all intrigued by the idea that there are more than the “three dimensions” (there’s "time" for a fourth dimension just to kickstart this puppy! . . .) might enjoy this little tickler for starters: “in everyday life, we inhabit a space of three dimensions – a vast ‘cupboard’ with height, width and depth, well known for centuries. less obviously, we can consider time as an additional, fourth dimension, as einstein famously revealed. but just as we are becoming more used to the idea of four dimensions, some theorists have made predictions wilder than even einstein had imagined.

string theory intriguingly suggests that six more dimensions exist, but are somehow hidden from our senses. they could be all around us, but curled up to be so tiny that we have never realized their existence. some string theorists have taken this idea further to explain a mystery of gravity that has perplexed physicists for some time – why is gravity so much weaker than the other fundamental forces? does its carrier, the graviton, exist and where? the idea is that we do not feel gravity’s full effect in the everyday world. gravity may appear weak only because its force is being shared with other spatial dimensions.”

well yeah, and then some . . . . . you see the universe has lots of secrets, not the least of which is the one relating to the apparent presence of a substantial amount of "stuff" that we can't detect. the lhc will provide some insight into all this " stuff" which scientists lump together under the moniker "dark matter". for the record, as things stand, all we see in the universe – planets, stars, galaxies – accounts for only a tiny 4% of it. it seems like it's time to start digging into "the rest". "the rest" is dark matter (23%) and dark energy (73%). physicists think the lhc could provide clues about this mysterious "stuff".

a sidebar to all of this exciting discovery stuff is the understandable anxiety that some people have around the "what-ifs" when this big boy is fired up. all sorts of ideas and theories are circulating around the possibility that the lhc might create miniature black holes, strangelets, magnetic monopoles, and vacuum bubbles. apparently c.e.r.n. is aware of these concerns and so each is addressed in lay terms that both describe the concern and then allays the fears of those who propose the concerns by providing an explanation as to why they should not be considered concerns. feel brave? want to scare yourself a little? then you definitely want to watch this . . .
if you would like to take a look inside the lhc and really appreciate the extraordinary scale and detail that articulates in its extraordinary confluence of technology the point that mankind is at then you should cruise through this powerful flickr set.
to really put all of this together for yourself you need to watch this incredible presentation . . . an excellent overview of the "best and worst case scenarios" with the lhc has been put together by the good folks over at "wired".

what an extraordinary time to be alive!

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