Large Hadron Collider turns back on - Earth survives!

[MattusMaximus]

Hooray! :D

Europe: Proton beams circulate in Big Bang machine (http://news.yahoo.com/s/ap/20091120/ap_on_sc/eu_sci_big_bang_machine)

And we're all still alive - yippie!

[andyandy]

just wait until they start colliding them.....:boxedin:

(i love how cutting edge physics basically boils down to getting two objects and hitting them together really hard just to see what happens.. :) )

[Sideroxylon]

Hooray! :D

Europe: Proton beams circulate in Big Bang machine (http://news.yahoo.com/s/ap/20091120/ap_on_sc/eu_sci_big_bang_machine)

And we're all still alive - yippie!

Or so you think ...
http://www.625.org.uk/ootu/bbcents/bbces208.htm

[MattusMaximus]

Or so you think ...
http://www.625.org.uk/ootu/bbcents/bbces208.htm

:confused:

[blobru]

Or so you think ...
http://www.625.org.uk/ootu/bbcents/bbces208.htm


Going to be a long short thread -- if Swanson Stevenson ... Sideroxylon is right. :alien002:

[not daSkeptic]

(i love how cutting edge physics basically boils down to getting two objects and hitting them together really hard just to see what happens.. :) )


From an early-90's British comedy show:
Physics is either accelerating subatomic particles to near light-speeds in an attempt to discover the ultimate origins of the universe, or it's melting some ice in a bucket.

[Wallmott]

http://twitter.com/cern/

You can follow them om Twitter and see what they are doing, they are doing live uppdates.

[jhunter1163]

just wait until they start colliding them.....:boxedin:

(i love how cutting edge physics basically boils down to getting two objects and hitting them together really hard just to see what happens.. :) )

As my father always used to say, "if brute force doesn't work, you aren't using enough."

[Wallmott]

Seems like there will be no High energy collisions this year, 1,2 TeV in each beam maximum with a little luck. Still makes it the worlds most powerfull accelerator.

A little bit OT, Does anyone know how cold the Tevatron is? As cold as the LHC?

[malbui]

I live next door to CERN. There was a very odd smell all across the village yesterday afternoon, but I assume it was because the farmers had been putting stuff on the fields rather than the fabric of space-time being altered.

[Wallmott]

Seems like there will be no High energy collisions this year, 1,2 TeV in each beam maximum with a little luck. Still makes it the worlds most powerfull accelerator.

A little bit OT, Does anyone know how cold the Tevatron is? As cold as the LHC?

And how cold is the RHIC?

[blobru]

I live next door to CERN. There was a very odd smell all across the village yesterday afternoon, but I assume it was because the farmers had been putting stuff on the fields rather than the fabric of space-time being altered.


Likely a spot of dark matter. :o

[Sideroxylon]

:confused:

If you like old-school SciFi download and listen to "Tunnel Under The World" from here:
http://www.oldradioworld.com/shows/X_Minus_One.php

[Evilgiraffe]

Seems like there will be no High energy collisions this year, 1,2 TeV in each beam maximum with a little luck. Still makes it the worlds most powerfull accelerator.

A little bit OT, Does anyone know how cold the Tevatron is? As cold as the LHC?

The figures I could find for each machines dipole magnets (bending magnets that steer the particles around the corners) are:

RHIC 4.3 - 4.6K

Tevatron 3.56K (lower than original design spec after an upgrade to the cryogenic system)

LHC 1.9K

It seem that the colder the machine is, the higher energies it can achieve. As to why this is I don't know, I'm not a particle physicist but there are some folk here who are.

[Dancing David]

This is the live lhc-webcams (http://www.cyriak.co.uk/lhc/lhc-webcams.html).


This has been posted before.

[~enigma~]

Hooray! :D

Europe: Proton beams circulate in Big Bang machine (http://news.yahoo.com/s/ap/20091120/ap_on_sc/eu_sci_big_bang_machine)

And we're all still alive - yippie!

http://www.cyriak.co.uk/lhc/lhc-webcams.html

ETA - Next time I'll read the whole thread first.

[MattusMaximus]

A little bit OT, Does anyone know how cold the Tevatron is? As cold as the LHC?

Yes, it is. They cool the Tevatron down to liquid helium temperatures - about 4 Kelvin.

ETA: My bad, the LHC is cooler than that, about 2 Kelvin. The reason for this is that the cryogenics cool down the superconducting electromagnets which are used to steer and focus the proton beams. At the velocities of the proton beams (roughly 99.9999991% lightspeed) they have an amazingly high relativistic mass and are therefore extremely difficult to turn, which requires a huge magnetic field to provide the necessary Lorentz force to turn the beamline.

[rjh01]

At that speed the protons must have a huge mass.

[CORed]

Hooray! :D

Europe: Proton beams circulate in Big Bang machine (http://news.yahoo.com/s/ap/20091120/ap_on_sc/eu_sci_big_bang_machine)

And we're all still alive - yippie!

Actually, the LHC destroyed the universe. Fortunately, it created a new one just like it, so we didn't notice.

[MattusMaximus]

At that speed the protons must have a huge mass.

Yup, at that velocity protons have a relativistic mass roughly 7500 times their rest mass!

[MattusMaximus]

Actually, the LHC destroyed the universe. Fortunately, it created a new one just like it, so we didn't notice.

Crap, I must have blinked and missed the whole thing ;)

[Nosi]

Likely a spot of dark matter. :o

Or strange matter?:scared:

[wuschel]

RHIC 4.3 - 4.6K

Tevatron 3.56K (lower than original design spec after an upgrade to the cryogenic system)

LHC 1.9K
Proving once again that science is cool!

[Evilgiraffe]

... and getting cooler!

[Wallmott]

Yes, it is. They cool the Tevatron down to liquid helium temperatures - about 4 Kelvin.

ETA: My bad, the LHC is cooler than that, about 2 Kelvin. The reason for this is that the cryogenics cool down the superconducting electromagnets which are used to steer and focus the proton beams. At the velocities of the proton beams (roughly 99.9999991% lightspeed) they have an amazingly high relativistic mass and are therefore extremely difficult to turn, which requires a huge magnetic field to provide the necessary Lorentz force to turn the beamline.

Is the place where the collisions takes place just as cold, ir is it a different temperature there?


Does anyone know what Walter L Wagner is doing now? Last year at the srart up he was all over the media, now there is nothing about it. Did he give up realising he was wrong?

[Hindmost]

I am hoping the LHC will form mini black holes which will suck all the woo out of the planet.

glenn:)

[MattusMaximus]

Does anyone know what Walter L Wagner is doing now? Last year at the srart up he was all over the media, now there is nothing about it. Did he give up realising he was wrong?

My guess is that the media rightly figured out that he's a clown to whom nobody should listen. But if, in the near future, there's a really slow news day, I wouldn't be surprised to see his mug pop back up on some news channel.

[Wallmott]

I have a question that i hope someone could answer.

Both LHC and RHIC has allot of safety reports on their websites about the unwanted stuff that some fear mongers were afraid could form in the collisions.

But i cant find any on the Tevatron which currently is the highest energy collider, but it collides protons and antiprotons and not protons to protons like RHIC and the LHC.

Is it that in theory micro bhs and sm and other stuff cant be formed in proton to antiproton collisions and just in collisions like RHIC etc? Just saying in theory because i know it is safe.

[Checkmite]

Progress on restarting the machine, on the border between Switzerland and France, went faster than expected Friday evening and the first beam circulated in a clockwise direction around the machine about 10 p.m., said James Gillies, spokesman for the European Organization for Nuclear Research.

"Some of the scientists had gone home and had to be called back in," Gillies told The Associated Press.

My father happened to be watching Fox News when the story that the LHC had been reactivated was announced. The reporter (I forget exactly who it was) made a point of mentioning in his introduction something along the lines of "Some even theorized it could create a black hole that would destroy the earth, although scientists have downplayed the suggestion" (I don't remember the exact words). He also mentioned at the end of the short piece that "There was something a bit unsettling - the collider actually turned on ahead of schedule, after the scientists had gone home for the night, and they had to be called back to work." This made it sound as if the machine started on its own, causing some kind of frantic rush by the scientists to get back to the lab.

According to this article, only some of the scientists had gone, and the rest were actually in the lab starting up the machine.

[Howie Felterbush]

As my father always used to say, "if brute force doesn't work, you aren't using enough."


My father had a similar saying..."Don't force it, get a bigger hammer."

Must be a dad thing.

[bpesta22]

just wait until they start colliding them.....:boxedin:

(i love how cutting edge physics basically boils down to getting two objects and hitting them together really hard just to see what happens.. :) )

You can describe marriage in this way too.

[shadron]

Collisions!! (non-marital)

http://news.discovery.com/space/first-proton-collisions-in-the-lhc.html

[daenku32]

Darned! So now I have to have dinner tomorrow night with both by mom and wife's step mom there.. Everything apparently has a downside.

[KingMerv00]

God, don't these guys get the hint? How many times to I need to sabotage the damn thing?

*Hops into time machine. Travels into future.*

[rjh01]

Two great videos on the LHC
OzR4eXIz_uA
TT2Q4kBhmXk

These people put out some very good science videos. These are typical.

[Cuddles]

It seem that the colder the machine is, the higher energies it can achieve. As to why this is I don't know, I'm not a particle physicist but there are some folk here who are.

The reason for differing temperatures is to do with how superconductivity actually works. It's not just the temperature that's important, things like the magnetic field, currents, stresses and so on all affect whether you're superconducting or not. You can think of it as similar to melting points. You can't just say that ice melts at 0o and leave it at that, the temperature varies with the pressure.

The LHC needs magnets with higher fields than other accelerators, but if you try actually getting those fields at the same temperatures they would stop being superconducting and wouldn't work at all.

Is the place where the collisions takes place just as cold, ir is it a different temperature there?

Only the magnets and some cabling are superconducting and need to be cooled. There's no need to cool down the rest of the machine, since that would just waste energy. The actual temperature at collision points may vary depending on the experiment (remember, there isn't a single collision point, there are four, with a different detector at each). For instance, the ATLAS detector uses superconducting magnets, while the ALICE one doesn't. What effect that has on the actual beam pipes an the centre of the detectors I'm not sure, but there certainly isn't deliberate cooling there.

Is it that in theory micro bhs and sm and other stuff cant be formed in proton to antiproton collisions and just in collisions like RHIC etc? Just saying in theory because i know it is safe.

No, it's nothing to do with the particles being collided. I assume it's simply because the people in charge of the Tevatron couldn't be arsed with taking all the wild claims by nutjobs seriously.

[CORed]

Crap, I must have blinked and missed the whole thing ;)

I wasn't really all that memorable. A brief instant of darkness and a faintly heard voice saying "Let there be light". I'm sure it had nothing to do with the shot of tequila I slammed just before it happened.

[Evilgiraffe]

The reason for differing temperatures is to do with how superconductivity actually works. It's not just the temperature that's important, things like the magnetic field, currents, stresses and so on all affect whether you're superconducting or not. You can think of it as similar to melting points. You can't just say that ice melts at 0o and leave it at that, the temperature varies with the pressure.

The LHC needs magnets with higher fields than other accelerators, but if you try actually getting those fields at the same temperatures they would stop being superconducting and wouldn't work at all.

Thanks Cuddles.

Superconductivity is a bit of a mystery to me. I touched briefly on the theory (Bardeen-Cooper-Schrieffer) during my undergrad but not since. As far as I understand, low temperatures are needed to stop lattice vibrations disrupting the paired electrons. I presume there is a similar limit to the magnetic field a superconductor can experience before the electron pairs are disrupted. Hence lower temperatures and less lattice disruption allow higher magnetic fields to coexist with the superconductivity. Is this anywhere near correct?

Only the magnets and some cabling are superconducting and need to be cooled. There's no need to cool down the rest of the machine, since that would just waste energy. The actual temperature at collision points may vary depending on the experiment (remember, there isn't a single collision point, there are four, with a different detector at each). For instance, the ATLAS detector uses superconducting magnets, while the ALICE one doesn't. What effect that has on the actual beam pipes an the centre of the detectors I'm not sure, but there certainly isn't deliberate cooling there.

Aren't the collision point under ultra-high vacuum? How do you define temperature when there is virtually no matter present?

[Mr Clingford]

http://news.bbc.co.uk/1/hi/sci/tech/8385891.stm

And the LHC surpasses 1 trillion electron volts. Apart from this being a new world record I don't know how to put it into perspective.

[Wallmott]

Everything seems to go very well at Cern and the LHC.

But im still wondering where all the fear mongers have gone, i have not heard anything from them for a long time and Walters web page has not been uppdated for a year or so.

[KingMerv00]

Everything seems to go very well at Cern and the LHC.

But im still wondering where all the fear mongers have gone, i have not heard anything from them for a long time and Walters web page has not been uppdated for a year or so.

Perhaps Walters' web page has been destroyed along with the rest of the Earth but the word has just not reached us yet.

[gambling_cruiser]

Last time we blew up the world our nwo department had to work overtime using superglue to fix it and we needed lots of neuron manupilators (you know them from MIB) to erase all the bad memories of this desaster.

[Ness36]

I know it is theoretical, and not agreed on by most physicists, but I am curious about the theory that backwards causality will cause the LHC to not produce a Higgs particle.

Here is the article:
Search for Effect of Influence from Future in Large Hadron Collider (http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1919v4.pdf)

Can anyone explain this theory, and why the Higgs particle in particular is thought to cause this effect? I have tried to read through the paper, but it is a little too complicated for me.

[rjh01]

Ness36, I think the article is a scientific way of saying "My dog ate my homework."

[MattusMaximus]

Everything seems to go very well at Cern and the LHC.

But im still wondering where all the fear mongers have gone, i have not heard anything from them for a long time and Walters web page has not been uppdated for a year or so.

My guess is they're off somewhere licking their wounds or attempting to come up with another doomsday scenario which will earn them a few minutes of undeserved fame in an otherwise scientifically-illiterate media-driven culture.

[MattusMaximus]

I know it is theoretical, and not agreed on by most physicists, but I am curious about the theory that backwards causality will cause the LHC to not produce a Higgs particle.

Here is the article:
Search for Effect of Influence from Future in Large Hadron Collider (http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1919v4.pdf)

Can anyone explain this theory, and why the Higgs particle in particular is thought to cause this effect? I have tried to read through the paper, but it is a little too complicated for me.

I made a detailed blog post about this awhile back when it hit the papers. If you're interested, here's the link...

The Large Hadron Collider – Where Does Science End & Pseudoscience Begin? (http://skepticalteacher.wordpress.com/2009/10/20/the-large-hadron-collider-where-does-science-end-pseudoscience-begin/)

Note that my post isn't a technical critique of the "backwards causality" notion, it's more of a commentary for the general layperson. My concluding thoughts in the blog post...

However, I will point out one thing which I don’t like about the article outlining Dr. Nielsen and Dr. Ninomiya’s work, and that has to do with what was said in this paragraph…

“It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.”

This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”

This displays sloppy reasoning of the highest order, in my opinion, and it shows that even mathematically brilliant physicists can fall prey to the most simple logical fallacies. In particular, Nielsen is illustrating the fallacy known as the argument from probability – he states that it is incredibly unlikely that the SSC would have been canceled by the U.S. government, so therefore it somehow constitutes evidence for his idea. I find this to be an overly broad definition of an “unlikely event” and positive evidence – with such loose & broad interpretations, one could take just about any “unlikely” event and attribute it to the “future sabotage theory.” In this form, Dr. Nielsen’s reasoning also smacks of the incorrect cause, argument from ignorance & the moving the goalpost fallacies.

So, what’s the bottom line here? I think the ideas proposed by Nielsen & Ninomiya are both provocative and interesting, especially since I’m a physics geek, but that simply isn’t enough to gain a new idea respect in the realm of science. Thus, until much, much, MUCH more evidence & testing comes to light on these questions, I shall remain as I currently am… skeptical.

[Ness36]

Thanks MattusMaximus.

I like your blog! Your article is very good. I think the two physicists who proposed this theory might just be exploring an interesting idea, not necessarily being psuedoscientific. Obviously if it works and makes Higgs particles, their theory will be falsified. I wanted to understand a little of the logic behind their hypothesis. It seems that they have more rationale than just the cancellation of the previous collider.

You are right that if a theory is non testable, it can never be more than a theory. The test of saying you will turn the collider on based on card draws assumes you absolutely must do the action assigned to the card, you can't change your mind or have other circumstances stop you. This seems impossible to achieve.

[MattusMaximus]

Thanks MattusMaximus.

I like your blog! Your article is very good. I think the two physicists who proposed this theory might just be exploring an interesting idea, not necessarily being psuedoscientific. Obviously if it works and makes Higgs particles, their theory will be falsified. I wanted to understand a little of the logic behind their hypothesis. It seems that they have more rationale than just the cancellation of the previous collider.

Thanks for the compliment.

You are right that if a theory is non testable, it can never be more than a theory. The test of saying you will turn the collider on based on card draws assumes you absolutely must do the action assigned to the card, you can't change your mind or have other circumstances stop you. This seems impossible to achieve.

Slight correction: if it's non-testable, there is no way it could even be a theory in the scientific sense. It would simply be speculation.

ETA: I downloaded the paper you linked, and I plan to read through it in the days to come. Thanks.

[Wallmott]

"This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”

Is that not just to far out there? That it stopped it before it was even built? How could it know?

To me it seems like one of the reasons for this was that they wanted some time in the headlines.

[Wallmott]

Another power failure at Cern.

http://www.theregister.co.uk/2009/12/02/lhc_power_failure_again/

[Cuddles]

Superconductivity is a bit of a mystery to me. I touched briefly on the theory (Bardeen-Cooper-Schrieffer) during my undergrad but not since. As far as I understand, low temperatures are needed to stop lattice vibrations disrupting the paired electrons. I presume there is a similar limit to the magnetic field a superconductor can experience before the electron pairs are disrupted. Hence lower temperatures and less lattice disruption allow higher magnetic fields to coexist with the superconductivity. Is this anywhere near correct?

Close enough. I'm far from an expert on superconductivity, so that would be about as far as my explanation could go as well. Of course, it depend on the nature of the superconductor as well. As far as I'm aware we still don't really know that much about how type-II superconductors work.

Aren't the collision point under ultra-high vacuum? How do you define temperature when there is virtually no matter present?

I assumed we were talking about the equipment around that point, rather than the actual collision point itself.

I know it is theoretical, and not agreed on by most physicists, but I am curious about the theory that backwards causality will cause the LHC to not produce a Higgs particle.

It's not a theory. It's a load of nonsensical sciency drivel. There's no point asking for the reasoning behind any of it, because there is no reason involved at any point.

[Emperor_Gestahl]

Let's see if we can actually go looking for the higgs-boson though. There are some fun star-treky theories where we are perhaps destroying all the worlds where it works leaving only the ones where something goes wrong as possible to have been observed by us. The prediction of that model of course is that something goes wrong again, and something always goes wrong every time for all eternity.

[Aitch]

Possibly even funnier is the idea that Stephen Fry was wittering about on a fairly recent QI - that when it does work it might create a time machine. The idea being that you need a machine at both ends of a time 'tunnel'.

He can be a right arts graduate at times. ;)

[Wallmott]

Does anyone know if they will be colliding with higher energys then 450 GeV this year? A while ago the schedule said that they would but it seems like there is allot to do before they move on.

And does not Cern have their christmas break soon?

[Cuddles]

Does anyone know if they will be colliding with higher energys then 450 GeV this year? A while ago the schedule said that they would but it seems like there is allot to do before they move on.

Technically collisions have already taken place at 1.18 TeV (per beam), since both beams have been accelerated up to that energy at the same time. I say technically, because the aim of those tests was solely to get the beams up to energy and make sure all the equipment was working. The beams were not optimised to produce lots of collisions, and no-one was actually looking for them. So in terms of not destroying the world, we know that some collisions must have taken place at these energies, but in terms of the actual commissioning and science they may as well not have happened.

The schedule itself is rather flexible and depends very much on how well various stages go. An overview of the basic plan can be found here (http://lhc-commissioning.web.cern.ch/lhc-commissioning/). It's possible that collisions at 3.5 TeV per beam will be started before the Christmas shutdown, but that's by no means certain. The latest official press release dates from 30/11 (http://press.web.cern.ch/press/PressReleases/Releases2009/PR18.09E.html), so I'm not sure exactly how things stand right now.

And does not Cern have their christmas break soon?

Yes. It shuts down for 2 weeks starting 17/12.

[Hindmost]

Technically collisions have already taken place at 1.18 TeV (per beam), since both beams have been accelerated up to that energy at the same time. I say technically, because the aim of those tests was solely to get the beams up to energy and make sure all the equipment was working. The beams were not optimised to produce lots of collisions, and no-one was actually looking for them. So in terms of not destroying the world, we know that some collisions must have taken place at these energies, but in terms of the actual commissioning and science they may as well not have happened.

The schedule itself is rather flexible and depends very much on how well various stages go. An overview of the basic plan can be found here (http://lhc-commissioning.web.cern.ch/lhc-commissioning/). It's possible that collisions at 3.5 TeV per beam will be started before the Christmas shutdown, but that's by no means certain. The latest official press release dates from 30/11 (http://press.web.cern.ch/press/PressReleases/Releases2009/PR18.09E.html), so I'm not sure exactly how things stand right now.



Yes. It shuts down for 2 weeks starting 17/12.

do they let the magnets warm up or keep them chilled?

glenn

[Cuddles]

do they let the magnets warm up or keep them chilled?

glenn

They'll keep them cold. It would take months to warm them up then cool them back down again, and the shutdown only lasts two weeks. Also, it's always better to try to keep things in a stable state. Warming and cooling things means expansion and contraction, along with all the stresses that causes. Unless you really need to warm things up to work on them, it will be preferred to always keep them cold.

[big-E]

My mate Brian Cox (yes *that* Professor Brian Cox, he's a Facebook friend of mine after meeting him at TAM London :D) posted a link to this a couple of days ago:

http://bit.ly/5fF9E1

"This is particularly nice. Two "jets" of particles from the collision. Standard stuff but never seen over 2 TeV"

So yeah, well over 450 GeV... but not really looking at the science in great detail yet.

[Hindmost]

They'll keep them cold. It would take months to warm them up then cool them back down again, and the shutdown only lasts two weeks. Also, it's always better to try to keep things in a stable state. Warming and cooling things means expansion and contraction, along with all the stresses that causes. Unless you really need to warm things up to work on them, it will be preferred to always keep them cold.

Exactly what I expected, but I didn't want to assume anything.

glenn

[Wallmott]

I read a Cern workers blog a while ago and they said that they wanted to accomplish as much as possible before the winter break because they would not have beems back in the LHC until early february at best. Why is that? What will they be doing in january?

[Cuddles]

My mate Brian Cox (yes *that* Professor Brian Cox, he's a Facebook friend of mine after meeting him at TAM London :D) posted a link to this a couple of days ago:

http://bit.ly/5fF9E1

"This is particularly nice. Two "jets" of particles from the collision. Standard stuff but never seen over 2 TeV"

So yeah, well over 450 GeV... but not really looking at the science in great detail yet.

Cool. I assumed they'd be looking at that sort of thing by now, but I couldn't find anything more recent than the announcement at the end of November on the CERN site. And considering this is the place that invented the internet, that site really is a mess.

I read a Cern workers blog a while ago and they said that they wanted to accomplish as much as possible before the winter break because they would not have beems back in the LHC until early february at best. Why is that? What will they be doing in january?

I've not heard anything about that. As far as I'm aware there's only a short shutdown over Christmas, after which everything will pick up where it left off.

[PingOfPong]

LHC planners have said that the LHC will idle during the winter to save money on energy. That was the plan last year before the massive failure.

[Denver]

New LHC Status (3/8/2010) (http://cdsweb.cern.ch/journal/CERNBulletin/2010/10/News%20Articles/1246745?ln=en):

Following the completion of the campaign to improve the reliability of the cabling for the new Quench Protection System, the main dipoles and quadrupoles of the eight LHC sectors have now been commissioned up to a current of 6 kAmps. In the early hours of Sunday 28 February, the beams were circulating again in the LHC: the longest run in CERN's history has just started!

...

High-energy collisions are planned for the end of March.

[GreenLines]

Oh no, the risk of strangelets and miniature black holes is just too much, it needs to be shut down!

[BenBurch]

Some woo on IRC the other day was saying that all the earthquakes were caused by the black hole that CERN made eating the planet from the inside...

:dl:

I don't know why I even bother with IRC any more.

[Nosi]

I don't know why I even bother with IRC any more.

From "Current illumni News" (http://www.expansions.com/News.cfm) comes this gem.

The Earth is being harvested by more than one group. They come from many different universes. The Hadron Collider in Geneva and the Fermi Labs Particle Beam Accelerator near Chicago both have the capacity to connect to other parallel universes.

:eek: HARVESTED?!? EEEEK!

[Dancing David]

Collect call from Universe B7Ts3592

"I was there at the sacking of the Great Palace of Zoomaregarneefo and posses the Treasure of Zeelotan however I need your help in getting it past the banking regulators. I will send you checks that you deposit in your account...

[MattTheTubaGuy]

Why are some people worried about micro black holes, etc.?
don't particle collisions of a similar magnitude happen in the upper atmosphere all the time?

I have no idea what I will be doing in 10 years, but working with a particle accelerator could be interesting.
I am doing a BSc majoring in Physics and Astronomy, just started my second year. I think it could be really quite interesting learning about all these strange particles (and others) and what they do!

[steenkh]

Why are some people worried about micro black holes, etc.?
don't particle collisions of a similar magnitude happen in the upper atmosphere all the time?
It seems that the argument goes that micro black holes formed by collisions by energetic cosmic rays and atoms on Earth will have a strong momentum carrying them away from Earth before they can accumulate enough mass to be a danger. Collisions in the LHC will have comparatively low momentum (the momentum of the two colliding rays will cancel each other out).

[Andrew Wiggin]

Aren't the collision point under ultra-high vacuum? How do you define temperature when there is virtually no matter present?

There is still radiation from the walls, since they're not absolute zero, and this would be absorbed by anything that WAS in the vacuum, so some of the concepts that accompany temperature still have some use.

A

[Mikemcc]

Aren't the collision point under ultra-high vacuum? How do you define temperature when there is virtually no matter present?I had the pleasure of working on the commissioning of Diamond Light Source in the UK (a recently constructed synchrotron). IIRC, the vacuum there was typically in the order of a 3-4x10-9 millibar. That still leaves about 1020 molecules m-3 of vapour in the vacuum vessel. The temperature of the vessel itself isn't important. The temperature of the magnets and RF devices are the important things as these are the devices drawing the heaviest currents (in DLS these were in the range of a few kA, as proven at LHC this will seriously ruin your day if the connections aren't perfect)

[Cuddles]

I had the pleasure of working on the commissioning of Diamond Light Source in the UK

Wait, really? That's where I am.

The temperature of the vessel itself isn't important.

Powered components are obviously more of a problem since they get hot just by being on, but overheating the vessel can distort it enough to break the vacuum. At low beam currents you'd probably need a fairly major miss-steer that shouldn't be possible, but at higher currents just impedance effects can be enough to cause significant heating, especially in areas with discontinuities like BPMs and flanges.

(in DLS these were in the range of a few kA, as proven at LHC this will seriously ruin your day if the connections aren't perfect)

As proven at Diamond as well. Not quite as impressively as at the LHC, but there have been some problems caused by overheating, including one fairly major vacuum leak.

[Evilgiraffe]

I had the pleasure of working on the commissioning of Diamond Light Source in the UK
Wait, really? That's where I am.


No, way... I have beam-time at Diamond. Scheduled for June, I think.

[/off-topic]

[Cuddles]

No, way... I have beam-time at Diamond. Scheduled for June, I think.

[/off-topic]

So you're one of those annoying users that keep spoiling our fun by actually using the beam instead of just letting us play around with it? Which beamline will you be at? And what do you people actually do, anyway?

[/entirely on topic, honest]

[TraneWreck]

Thanks for the compliment.



Slight correction: if it's non-testable, there is no way it could even be a theory in the scientific sense. It would simply be speculation.

ETA: I downloaded the paper you linked, and I plan to read through it in the days to come. Thanks.

Since you've volunteered yourself as resident expert, I have a question about all of this:

One of the fears you hear about the Hadron is that it will create a mini-black hole that will consume the Earth.

I understand black holes to have intense gravity because the mass of a star collapses into a small space. Clearly there is nothing on Earth that remotely has the mass of a star, so how could we create a black hole?

Or can smaller amounts of mass be sufficient? Are there any equations on this--as in--Star X leads to black hole sized X; collapsing the matter of the Empire State building leads to a black hole with characteristics...?

Just curious about all of this.

[TraneWreck]

Some woo on IRC the other day was saying that all the earthquakes were caused by the black hole that CERN made eating the planet from the inside...

:dl:

I don't know why I even bother with IRC any more.

Because there's no other way to fill that comedy void.

[Cuddles]

I understand black holes to have intense gravity because the mass of a star collapses into a small space. Clearly there is nothing on Earth that remotely has the mass of a star, so how could we create a black hole?

Or can smaller amounts of mass be sufficient? Are there any equations on this--as in--Star X leads to black hole sized X; collapsing the matter of the Empire State building leads to a black hole with characteristics...?

Just curious about all of this.

Any amount of mass can be sufficient. The less mass you have, the smaller the black hole, but in theory any amount of mass has an associated size (the Schwarzschild radius) at which it will collapse into a black hole. Obviously any black holes resulting from particle collisions will be rather small, but it's still entirely possible for them to exist.

With the LHC, the question is not so much whether such black holes can exist, but simply whether they could actually be created in those collisions or if they require much more extreme conditions than we can create at the moment. As it stands, mainstream theories say that they can't be created by the LHC, and it's only less well supported theories that suggest they might be.

[TraneWreck]

Any amount of mass can be sufficient. The less mass you have, the smaller the black hole, but in theory any amount of mass has an associated size (the Schwarzschild radius) at which it will collapse into a black hole. Obviously any black holes resulting from particle collisions will be rather small, but it's still entirely possible for them to exist.

With the LHC, the question is not so much whether such black holes can exist, but simply whether they could actually be created in those collisions or if they require much more extreme conditions than we can create at the moment. As it stands, mainstream theories say that they can't be created by the LHC, and it's only less well supported theories that suggest they might be.

So would a black hole created by two particles colliding have just the mass of those two particles? Do black holes gain strength as they absorb other objects? If they do, that might be slightly concerning as a small black hole could start growing atom by atom.

And lastly, are there any theories about how much mass would be required to give a black hole enough power to absorb the Earth?

You guys don't have to answer everything, if there are good resources about this stuff just point the way.

[Cuddles]

So would a black hole created by two particles colliding have just the mass of those two particles?

Well, it would have the mass equivalent of the energy of the two particles. That's why the fuss is about the LHC - the particles it's colliding are no different from those used in other colliders, but the energies are (or at least will be) much higher than we've produced before.

Do black holes gain strength as they absorb other objects?

If by "strength" you mean mass and size, yes.

If they do, that might be slightly concerning as a small black hole could start growing atom by atom.

This is where Hawking comes to save the day. It turns out that everything that falls into a black hole is not lost forever, black holes actually radiate energy. The physics behind it is a little complex, but essentially it's to do with pair production right at the event horizon, where one of the pair falls into the black hole while the other escapes. The result is that the event horizon of a black hole continually radiates energy. The interesting part is that the rate energy is radiated depends on the inverse of the mass of the hole, so a large black hole can last for billions and billions of years, while a very small one will evaporate almost instantly.

So the question then is, assuming micro-black holes actually could be produced in the LHC, would they be able to consume matter faster than they evaporate? This is a bit of a tricky one. If the black hole is moving too fast, it will just shoot straight through the Earth and disappear off into space, where it will quickly evaporate since there's not much matter out there. On the other hand, if it's moving too slowly, it won't reach any matter before it evaporates. If I remember correctly, it turns out that it's extremely unlikely, but still possible, for a black hole produced during a collision to reach the walls of the collision chamber, but still be travelling slow enough not to escape. This tends to make the alarmists rather excited, so much so that they forget that no accepted theory predicts black holes could be created in the first place.

And lastly, are there any theories about how much mass would be required to give a black hole enough power to absorb the Earth?

As hopefully explained above, there is no limit. As long as a black hole can consume matter faster than it radiates Hawking radiation, it will grow in mass and size. On the plus side, eating an entire planet one atom at a time is not a fast process. It would take something on the order of billions of years for a black hole to grow large enough to make the Earth structurally unstable.

You guys don't have to answer everything, if there are good resources about this stuff just point the way.

I'd actually recommend Wikipedia. When it comes to sensible physics subjects it usually tends to be quite good, although it often contains rather more equations than might be ideal for the layperson.

[dudalb]

So Gordon Freeman did not screw things up this time?

[TraneWreck]

Well, it would have the mass equivalent of the energy of the two particles. That's why the fuss is about the LHC - the particles it's colliding are no different from those used in other colliders, but the energies are (or at least will be) much higher than we've produced before.

[...]

I'd actually recommend Wikipedia. When it comes to sensible physics subjects it usually tends to be quite good, although it often contains rather more equations than might be ideal for the layperson.

I appreciate the info. I sort of feel like I'm asking the same level of questions about physics that my mom asks me about sports, "why did that guy just fall down?"

[Haig]

CERN's Large Hadron Collider, world's largest atom-smasher, needs to be shut down for repairs (http://www.nydailynews.com/news/world/2010/03/10/2010-03-10_cerns_large_hadron_collider_worlds_largest_atom smasher_needs_to_be_shut_down_for.html)

The European Organization for Nuclear Research's (CERN) state-of-the-art machine - which sends subatomic particles crashing into each other at unprecedented speeds - must be taken offline at the end of 2011 for a year of maintenance to correct several design issues and add failsafe systems, the BBC reported.

"It's something that, with a lot more resources and with a lot more manpower and quality control, possibly could have been avoided, but I have difficulty in thinking that this is something that was a design error," Dr. Steve Myers, a project director"

[shadron]

CERN's Large Hadron Collider, world's largest atom-smasher, needs to be shut down for repairs (http://www.nydailynews.com/news/world/2010/03/10/2010-03-10_cerns_large_hadron_collider_worlds_largest_atom smasher_needs_to_be_shut_down_for.html)

The European Organization for Nuclear Research's (CERN) state-of-the-art machine - which sends subatomic particles crashing into each other at unprecedented speeds - must be taken offline at the end of 2011 for a year of maintenance to correct several design issues and add failsafe systems, the BBC reported.

"It's something that, with a lot more resources and with a lot more manpower and quality control, possibly could have been avoided, but I have difficulty in thinking that this is something that was a design error," Dr. Steve Myers, a project director"

That's just about the most uninformative article I think I've ever read. What the hell is Myers saying? no amplification at all about what has been discovered wrong - and why in 2011 rather than now, or 2020?

[Cuddles]

That's just about the most uninformative article I think I've ever read. What the hell is Myers saying? no amplification at all about what has been discovered wrong

It's hard to say what they're talking about without more information. I can't find anything about this either on Cern's site or on the BBC which apparently reported it. It's already known that there are various problems with the LHC, which is why it was delayed so much in actually getting started up in the first place. This report is most likely nothing more than a timetable for the fixes being given, rather than there actually being any new developments.

and why in 2011 rather than now, or 2020?

In 2010, particles will only reach 3.5TeV, which is well below the maximum planned. 5TeV has been discussed, but is apparently no longer planned during 2010 and will presumably happen in 2011 (see here (http://lhc-commissioning.web.cern.ch/lhc-commissioning/). Obviously waiting until 2020 would be rather silly, since that would waste a whole decade, and there's plenty of work to be done before any upgrades can actually be made so there's no point trying to rush into it right now and waste time that could be spent on commissioning and lower energy (but still higher than ever before) physics.

[Mr Clingford]

http://news.bbc.co.uk/1/hi/sci/tech/8556621.stm

"The Large Hadron Collider (LHC) must close at the end of 2011 for up to a year to address design issues, according to an LHC director.

Dr Steve Myers told BBC News the faults will delay the machine reaching its full potential for two years."

[shadron]

In 2010, particles will only reach 3.5TeV, which is well below the maximum planned. 5TeV has been discussed, but is apparently no longer planned during 2010 and will presumably happen in 2011 (see here (http://lhc-commissioning.web.cern.ch/lhc-commissioning/). Obviously waiting until 2020 would be rather silly, since that would waste a whole decade, and there's plenty of work to be done before any upgrades can actually be made so there's no point trying to rush into it right now and waste time that could be spent on commissioning and lower energy (but still higher than ever before) physics.

Yes, I agree. I was wondering why the article could not be a little more forthcoming about why they're pushing the journalistic panic button. Thanks for off-handedly being more informative than the news covering Steven Myers, cuddles.

[dudalb]

CERN's Large Hadron Collider, world's largest atom-smasher, needs to be shut down for repairs (http://www.nydailynews.com/news/world/2010/03/10/2010-03-10_cerns_large_hadron_collider_worlds_largest_atom smasher_needs_to_be_shut_down_for.html)

The European Organization for Nuclear Research's (CERN) state-of-the-art machine - which sends subatomic particles crashing into each other at unprecedented speeds - must be taken offline at the end of 2011 for a year of maintenance to correct several design issues and add failsafe systems, the BBC reported.

"It's something that, with a lot more resources and with a lot more manpower and quality control, possibly could have been avoided, but I have difficulty in thinking that this is something that was a design error," Dr. Steve Myers, a project director"

I am telling you, they need to fire Gordon Freeman....

[Wallmott]

The LHC just reaches 3,5 TeV with each beam running in the machine.

Does that mean that they have collided at any time?

[23_Tauri]

But hang on, it's the end of the moon sun! :eek:

It must be true because a boffin said so. Ok, so his professorship's in chemistry, but let's overlook that in favour of a prize tin foil hat moment...

http://www.theregister.co.uk/2010/03/16/lhc_sun_moon_doom/

Rössler says Hawking is wrong, and has written to tell him so, but without any reply so far.
Arf...

[Checkmite]

In 2010, particles will only reach 3.5TeV, which is well below the maximum planned. 5TeV has been discussed, but is apparently no longer planned during 2010 and will presumably happen in 2011 (see here (http://lhc-commissioning.web.cern.ch/lhc-commissioning/).


The machine has to run a whole year to get the particles going that fast?

[Evilgiraffe]

But hang on, it's the end of the moon sun! :eek:

It must be true because a boffin said so. Ok, so his professorship's in chemistry, but let's overlook that in favour of a prize tin foil hat moment...

http://www.theregister.co.uk/2010/03/16/lhc_sun_moon_doom/


Arf...

From the same article.

Also it has to be said that the sudden change of mind on the safety of a lunar-base LHC - and indeed his vehement insistence that putting it on the Moon would only double or triple the Collider's cost - tend rather to undermine Rössler's credibility, too.

I'll see your Arf... and raise you a snerk.

[Cuddles]

The LHC just reaches 3,5 TeV with each beam running in the machine. Does that mean that they have collided at any time?

Collisions first occurred before Christmas, although only as preliminary tests and not as part of any physics experiments. Those were at 2.36TeV (1.18 for each beam). Just today, they established both beams at 3.5TeV, but have not collided them at that energy yet.

The machine has to run a whole year to get the particles going that fast?

No, it's had them running that fast already. However, there's a big difference between getting a few particles up to the right energy and actually getting high current, stable, correct shape and size beams reliably colliding in the right place at the right time in a safe way. And since these energies are already well above anything achieved before, there's plenty of science that can be done at these levels without having to rush to higher numbers.

[MattusMaximus]

3.5 TeV beam-line energies... and we're all still alive.

Ah, those silly scare mongers :)

[ArmillarySphere]

http://hasthelargehadroncolliderdestroyedtheworldyet.com/

[Cuddles]

http://hasthelargehadroncolliderdestroyedtheworldyet.com/

The thing I particularly like about that site is that it's not just static text, there's actually a script that adjusts the text based on whether the world has ended or not.