What Are Must-Sees For Open Day At the LHC? 210
ribasushi writes "The last open day at the Large Hadron Collider is one week away. While I have a solid chance to go, I am dumbstruck by the insane amount of things to see during the 10 hours of the event. Since I do not know all that much about physics, I am turning to the knowledgeable crowd here at Slashdot — what do you think are the most awesome 5 must-see things on the agenda next Sunday?"
Obligatory (Score:5, Funny)
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Be Prepared! (Score:2)
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That out of the way, you must see CMS or ATLAS, preferably both. This really is your last chance to see them. I work on CMS and even I probably will have major difficulties seeing it ever again after this saturday. The shear scale of these detectors are breathtaking, they are several stories high and look ev
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Black Holes (Score:4, Funny)
Re:Black Holes (Score:5, Funny)
-Lasse
Re:Black Holes (Score:5, Funny)
They could sell the Black Holes they make in their gift shop, so everyone can have a Black Hole waste disposable system at home.
I can't wait for the LHC Gift Shop to start selling Small Hadron Colliders
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I suspect that for most people, there isn't anything of interest to see at the LHC. Miles of corridors, rather non-impressive machinery, and a bunch of workstations. The receptionist might be the most spectacular sight. The results from the LHC will be interesting, but those you don't have to go to the site to see.
Re:Black Holes (Score:5, Informative)
1- They emit black body radiation at the Hawkings temperature due to quantum evaporation, which for a tiny black hole is very high. A black hole created by an accelerator, composed of the mass of a few particles would likely be extremely hot for a very short time, and so would emit gamma rays. Wikipedia has the calculation for a 1kg BH : the lifetime is approximately 10^{-16} seconds, and the energy output equivalent to the complete anihilation of the 1kg mass (you don't want to be around). Small black holes are *fierce*, however subatomic ones don't really matter. After all accelerators anihiliate particles all the time.
The above is the #1 reason BH potentially created by accelerators are not a concern.
2- Even very large BH are in fact directly visible. They reflect light better [obspm.fr] than a highly polished metallic sphere.
These two facts are direct illustrations that most people, including well-educated scientists, don't know the first thing about BH.
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Your link is talking about light being bent by the hole's gravitational field.
Don't be so quick to criticise those "well-educated scientists".
That's "refract" (Score:2)
Re:Black Holes (Score:5, Informative)
First what is a black hole? Let's say we mean the event horizon. That does not reflect light at all. However, the gravitational field surrounding the BH will of course deflect light the same way the gravitational field around a massive star for example would. Therefore the OP was entirely correct, we can only see the effect of the gravitational field but not light emanating from the BH itself. (At least for astronomical BHs that are very massive and have correspondingly low Hawking temperature). Even taking Hawking temperature into account a BH never reflects light, it has a temperature and gives off perfect black body radiation (in the semi-classical approximation which is the only thing we really know about). That is the black hole information paradox, the outgoing radiation seems to have no information about the ingoing one.
A super-massive blackhole in empty space would be one of the darkest objects you could think of (arbitrarily cold, negative specific heat, yadda yadda). Put some infalling matter around it and you get very bright and energetic processes so BHs can power very bright objects in their vincinity. Put some galaxies and stars behind it and it can lense the light coming from these, put some stars in front it and it can deflect a small amount of light so strongly that it comes straight back at you. That is really due to the space time structure induced by its mass, you don't need a BH for either of these effects. Furthermore you wouldn't say a lense is very bright would you? Nor that it reflects light.
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Why don't you read the book chapter I linked to and reply to the points it makes ? I find it very enlightening
I'm only a mathematician and computer scientist, but J.P. Luminet, the author of the chapter I linked to in the GP, is definitely a physicist and a specialist on BH as well as a great writer. In it he compares the light output of a number of bodies, including a perfectly black, matte sphere, a highly polished metallic sphere an
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You don't see the black hole itself, you see the effect of gamma rays hitting nearby matter. Or did you imply that gamma rays are visible to you?
This claim requires a reference.
You also seem to forget that black holes curve light around them. If you have a black
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BH have a non-zero temperature, so they emit black body radiation. BB radiation emits at *all* wavelengths, regardless of the temperature, so including visible wavelengths. This is so regardless of the mass of the BH. At the right mass, a BH can emit mainly in the visible part of the spectrum, and so be very visible in all senses of the word.
I have provided a reference to the "reflected light" claim. Please go read it, or look for "Luminet Black Holes" in Google. Happy reading.
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No, but its gravitational field distorts light like a lens. It can bend light more than 180 degrees (imagine photon traverses black hole like a comet approaching the sun), so some part of the image might actually be reflection, like a mirror.
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If I put you in the outer space, you are not light emitting either. The fact I can see you is because you reflect light either from the sun or the computer screen in front of you.
That said, isn't it surprising when scientists find out that most objects out there aren't light emitting? Like, dark matter?
Ask them... (Score:2, Funny)
Flux Capacitors (Score:5, Funny)
Other must-sees (Score:5, Funny)
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Crowbar (Score:5, Funny)
Re:Crowbar (Score:5, Funny)
Bring a can of spray paint, just in case.
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So, if you want to use a crowbar, just be sure it is made of something (more or less) non-magnetic, such as 300-series stainless steel or titanium alloy.
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I ask one thing (Score:5, Funny)
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Re:I ask one thing (Score:4, Funny)
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The black hole (Score:3, Funny)
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NY Times article, blackholes?! strange matter?! (Score:3, Informative)
Re:NY Times article, blackholes?! strange matter?! (Score:4, Funny)
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Oh! (Score:2)
Appreciation (Score:5, Insightful)
Re:Appreciation (Score:5, Insightful)
Agreed (Score:2)
Re:Agreed (Score:5, Informative)
The thing is that at CERN almost everyone is clueful but about "one thing" mostly. It is hard to find someone who has the "large picture"... The ones who do are generally people who have not been working on the LHC for the past 15 years but those who have been working on it since 2-3 years and before that was working at Fermilab or somewhere else like that. Then they can tell you what's new or revolutionary and put things in better perspective.
Honestly, it looks like the OpenDay will be a mad house. We are expecting at least 40,000 people. The queues are going to be awfully long! I feel like we should have a couple more of these OpenDays to accommodate this huge interest but hey, I am not in the management!! I am just a post-doc!
That said, I have given lots of tours at CERN already. I have taken at least 400 people underground just this past year. (Only 12 people are allowed to go at a time with one guide... ) I think the well-known things like ATLAS and CMS will be completely and utterly packed. So I would like to point out a rare gem... It's the LHC-b cavern where you can actually see the insides of the experiment which installed before LHC-b was installed and is now decommissioned and sitting nearby. The problem with ATLAS and CMS is that they are "done" -- meaning, the experiments are assembled wholly and therefore, it is hard to see it's guts. But you can see the guts of this decommissioned detector, which is kind of neat. I work for ATLAS and I love ATLAS to pieces but I think to try to see it on Open Day, one would need to be at CERN and queueing at 8am... or earlier.
If you have never seen a tape reader with robots running around before, the tour to the Computing Center is really cool -- but then again, since there will be no radiation there, you can visit that even after the 1st of May. (1st of May is the date set by the LHC management board to be the last day of public tours to the LHC and experiments. The rest of CERN will still be "visitable" after that.)
If you can not see ATLAS or CMS on the OpenDay or cant be here on the OpenDay but want to see them, there is a cheat... Most of everyone's requests goes through CERN Visitors Service. And they have a pool of guides but the experiments also have a pool of guides. The visitors service is no longer offering tours as they are completely booked until the 1st of May with their guides. But the experiments might still allow for visitors. The way to increase your chances of getting a private tour to one of the experiments is as follows: Find 11 other people who are interested in seeing the experiment with you and then e-mail the ATLAS or CMS secretariat asking for a tour for 12 people on a April xxth at xx:xx. Then they will forward this request to their pool of guides and someone (like me) might actually give you a tour. We like 12 people tours as this is the maximum we can take down and it is a much better "waste" of our time if the tour group is at maximum number... The e-mails for the secretariats are as follows: atlas.secretariat@cern.ch and cms.secretariat@cern.ch
Good luck!
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Please... (Score:5, Funny)
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Re:Please... (Score:5, Funny)
Actually, a lot of bosons are free of charge.
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A neutron walks into a bar.
Neutron: One beer please
Barman hands neutron a beer
Neutron: How much is that?
Barman: To you? No charge!
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I'd go see the Atlas detector.. (Score:5, Interesting)
which shows that it's a large open house event with many activities.
Anyhoo, the Atlas detector looked very cool in a magazine I read recently (National Geographic?).
Personally I'd also try to see one of the pulse power supplies that drives the LHC injector kicker magnets, because my father's team designed them.
http://www.triumf.ca/publications/pub/arch05/pp-05-19.pdf [triumf.ca]
Yes you can tell I'm proud of him!
What I'd like to see... (Score:5, Funny)
You can get the answer by repeatedly asking 'What does this button do?'
Re:What I'd like to see... (Score:5, Funny)
Big buttons (Score:2)
Obvious (Score:2)
If that doesn't work out, you can ask to see just about any other particle they make around there, there's certainly enough of them. But whatever you do, don't bring up Lexx...
see the detectors (Score:4, Interesting)
Have fun!
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Mod Parent Up, Please (Score:2)
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It is the layer of the ATLAS detector that is closest to the interaction point where collisions happen. The first layer (cylinderical) only 5 cm away.
As for the radioactivity being "potentially dangerous" -- well, I would not want to ingest any of it or sleep next to it, if that's what you mean... But actually no, we will be able to take the detector out and replace it if needed. Remember that exposure is what counts and that depends on distance, as well as how long you have been e
Placebos (Score:2)
So I've done a bit of thinking about this and my conclusion is that it's a combination of placebo effect and the presence of knowledgeable scientists who are good public speakers. In other words we could tell you
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Go see the detectors (Score:3, Interesting)
A serious answer (Score:5, Informative)
If you have any interest at all in the detectors or accelerator, now's the time. Spend your time there; because, you won't be able to "tour" it later. Once it's been running the equipment will become activated (as in radioactive) and the public will no longer be able to tour the underground facilities. There will likely be physicists and technicians on hand who will be happy (excited even) to talk about what they've built.
you can always go back and look at the computer center, control rooms, or whatever at a future open house event (which I'm certain they'll have regularly, to keep the public interested).
For what it's worth, I worked as a technician at a U.S. DOE facility
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Your right that the activated materials are short lived, typically with half-lives on the order of hours. At JLab (which is a very low energy facility compared to some others) we typically allow a cool-down period of a week or so, after the accelerator has shut down, before we start the serious work on the detector systems. There's very little risk associated with working around the equipment.
My point was, however, that once beam has been introduced into the end station, we no longer allowed people into
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A reply to myself, I had further insight...
This lack of willingness to allow mass numbers of visitors in during the open houses might be more "political" than anything else. You could certainly rope off safe areas where you could run guided tours. Unfortunately, here in the U.S., the general public still has some irrational fears concerning anything "nuclear" or "radioactive" and you can't help but be exposed to the signage, placards, warning labels, etc.
Maybe your in a better position in Europe?
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Nicely Formatted (Score:5, Informative)
I'm a student here working on ATLAS (and I'll be one of the volunteers on the 6th) and I agree with the parent. The two big 'Must sees' are the detectors and the accelerators. The detectors are going to be much more impresive looking. That said, here's my $0.02
ATLAS (point1). This is the biggest detector (and my favorite, though I'm not biased or anything....) but it will also be the most crowded by far.
CMS (point5). Almost as big as ATLAS and still damn impressive. It won't be as crowded because it's a lot further away. It will still be packed though I'm sure.
ALICE (point2). Smaller detector for heavy ions. My guess is this will be pretty crowded to since St Genis is close to CERN
LHCb (point8). Another smaller detector for b quark physics. Between Ferney and Meyrin... no idea if people will go see it.
Those are the 4 detectors ranked (in my opinion) in order of coolness. I'd try to go see 2 of them if you can. Look up info on them online (they all have websites), find out which ones you want to visit. You should also try to see the accelerator somewhere. Point 6 would be my recomendation since the beam dump is also located there (this is where the beam is evacuated in case of emergency. When you realize the energy stored in the beam, this becomes pretty impressive).
Another thing I recomend is the acelerator chain tour (point1):
http://lhc2008.web.cern.ch/LHC2008/OpenDaysE/accelerators.html [web.cern.ch]
There are a lot of other things open, but most of them you can still go and visit when the LHC is running (and the crowds aren't there). One last recomendation. I'd start out going to see things out on the ring, then come back to point1 (Meyrin) and explore it with all the rest of your time. That way you should be able to get the most out of it. See you Sunday!
Compulsory T-Shirt (Score:5, Funny)
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Watch the beam dump. (Score:2)
I would recommend to be in the vicinity of the "beam dump" when the beam for on of about a million failsafe conditions is aimed there.
If nothing happens, you can probably induce a beamdump in any of a thousand ways. Use your imagination, or just look for big red buttons.
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See http://scienceworld.wolfram.com/physics/MagneticFieldEnergyDensity.html [wolfram.com]
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Ask why they call it "Large" (Score:2)
"Oh, excuse me, Dr. Physicist, I wouldn't have known if you hadn't told me." Stupid physicists.
(Though perhaps it's that physicists contracted out to the folks who classify shrimp...next up, the "Jumbo Hadron.")
"Mmmm...Jumbo Hadrons"
Simple (Score:3, Funny)
Thank you, thank you, I'll be here all week, try the fish!
Things to check out (Score:5, Informative)
- before you do anything, check the Microcosm museum in the reception building. This one will explain a lot what's happening.
- this one is a must: be sure to make a trip to either the ATLAS or CMS cavern (those are the two bigger detectors attached to the LHC)
- the ATLAS control room
- the LHC control room
- the computing centre in the IT building
- and if you have time, stop by for a tea in building 40
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>and if you have time, stop by for a tea in building 40
Blatant ATLAS propaganda.
No no, you should come to the computing centre, or CMS.
In all seriousness I agree with my colleague above. Microcosm is worth a visit, but the must-see is one of the caverns(ATLAS,CMS).
They are not quite so impressive now that they have been filled completely with detectors, but still very interesting. As mentioned
in another post above the control rooms and computer centre will probably stay
Must See (Score:2, Informative)
If you're interested in detectors you have enough time to visit at least two of the four major experiments. CMS is a bit far away, it takes you some 20 minutes by bus to go there, ALICE and LHCb are closer and ATLAS is just across the road opposite the main entrance. I would recommend ALICE and ATLAS - ATLAS is, just like CMS
Comment thread for nerds. Some stuff matters. (Score:2, Insightful)
best thing to see there? (Score:2)
See if you can find... (Score:2, Funny)
Recycling? (Score:3, Funny)
Ask them if this is the last chance to perform this experiment before physicists realize that it will cause a big bang and inflationary event which will recycle the present universe.
Ask them if this is the same experiment that was done 20 billion light years away and that put on a show called the Star of Bethlehem 2000 years ago.
Ask them if the only proof that they will cause a big bang is that there cannot be any proof until the experiment is performed. (See also 'The Hound of the Baskervilles')
Ask them if it is necessary to do the experiment because we've been doing it for infinity and if we don't the universe will fade away forever.
Ask them if we have to do it because if we don't some other nearby civilization will beat us to it and we'll eat their dust.
Am I in trouble ... (Score:2, Funny)
They don't sell it over the net.
So I tried eBay.
No luck, but there was some superconducting parafinelia for some $10K. So I asked
How much to ship to Iran
G
Cafeteria & Mont Blanc (Score:2)
Also have a look at Mont Blanc, which you can see when you're in front of the LHC building. It's a very nice view.
Which Day is the End of the World? (Score:2)
Ever wondered what it would be like if they generated a large, non-disappearing black hole?
Would the world die?
The first web page ever written. (Score:2)
I'm sure you were expecting .. (Score:3, Funny)
Re:Hahaha (Score:4, Funny)
How's that for knowledgeable!?
*barely dodges flak*
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