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Large Hadron Collider restarts after two-year rebuild (bbc.com)
156 points by raverbashing on Apr 5, 2015 | hide | past | web | favorite | 35 comments

I see it makes network calls in dev tools. Is this live? Because if it is then that's fascinating.

Yes, these public displays (internally called vistars or fixed displays) are a real-time stream. Essentially the same that's being broadcasted in the Control Center (the CCC), but at a (much) lower frame rate.

You can navigate and find others, like the ones focused on the luminosity that the experiments are getting (not yet useful), or on the injector accelerators.

(I was working on the vistar project for a year.)

What kind of tools are used to build those dashboards and data streaming systems? Anything you'd want to use for regular system monitoring? Looks like part of it might be Gnuplot?

It reminds me a bit of the factories or refineries that have elaborate control flow systems. In software, Netflix's Hystrix dashboards are a fun inspiration for example: http://techblog.netflix.com/2012/12/hystrix-dashboard-and-tu...

I've always wanted to build a visualization like that for the systems I work on :-)

Java Swing. Not the fanciest, I know.

We had a powerful framework to create graphical elements that display values from the hardware.

The previous version of these displays was teletext (do you remember what that is?), with some analog signals sometimes directly overlayed onto them. So, considering we came from that, Java Swing is quite a technology leap :)

> (I was working on the vistar project for a year.)

Nice work! I used to work in the ROC at Fermilab ~5 years ago (CMS datataking). I'm astounded by how many people I run into who have worked on the LHC data side.

It seems to be live. Data is changing without needing to refresh

It is live, see the help link in the lower right corner.

Yes. It is live.

the Tech.Info button link is dead redirecting to wikis/display/COIN/Machine+Status+Pages

OT - SEO/Google-juice:

Glyphish domain must get some serious value out of being linked from cern.ch pages regardless of the fact CERN about to be linked from many of the social media sites. Wonder how much revenue that simple connection will earn.

Interestingly it seems the link was only required because CERN didn't want to pay the $99 license?

He is reborn!

Took me a minute to remember this is a religious holiday, and that this is a joke based on it.

Is it just me or is the large Hadron collider really scary in how it can start a black hole chain reaction?

No, and here's a really detailed explanation as to why this couldn't possibly happen:



1.) If these miniature black holes exist, the Earth has been getting hit by them for billions of years, and it’s still here. 2.) If you do create a miniature black hole, they will decay, via Hawking Radiation, on ridiculously small timescales. 3.) You can compute the rate at which a black hole eats matter, and it’s not even close to being as small as the lifetime of our planet.

  the rate at which a black hole eats matter...

  ...it’s not even close to being as small as the 
  lifetime of our planet.
So the duration of time in which any given black hole might eat an amount of matter takes a lot longer than the age of the earth?

I think it's important to note that these things being discussed would potentially be micro-singularities, smaller than anything that might be visible to the naked eye.

Otherwise, it's pretty obvious that a planetary-scale black hole could handily destroy the earth in short order, by way of mere collision, whether consumes all of the earth's matter beyond its event horizon or not.

...anyway, yeah, the LHC's capacity for stranglets is otherwise negligible, and not very worrisome at all.

A sustained chain reaction requires a lot of things that here don't look likely to be set.

On the other hand, some ants playing with insecticide indeed searched for a sustained chain reaction and yieled x3 the anticipated output during operation Castle Bravo


Nope! Cosmic radiation causes much higher energy collisions in our atmosphere every microsecond of every day. Even if those collisions form black holes, our continued existence as non-singularities is evidence enough that they're not an issue.

Physicists have looked at all the angles on this, and are pretty certain there's nothing the LHC could do that would pose a threat to the world.

On the other hand, the universe still looks pretty empty of extraterrestrial civilizations, despite the availability of nice planets and so forth. Perhaps they were all pretty certain too.

You can watch the live stream of the webcam on location if you are concerned about this: https://www.youtube.com/watch?v=9JYkMhQ9gf8

Can you explain? The LHC produces energies that are less than what the earth has been bombarded with from cosmic sources since time immemorial.

Also what exactly is a "black hole chain reaction"? How are these black holes possible exactly? The energy involved in a single proton are not enough for a stable microscopic black hole to form. This is presuming it even CAN form (its at best a hypothesis) given our understanding of gravity.

I guess is fear to unknown and unanticipated phenomena. Crazy high unpredicted outputs happened before (google operation Castle Bravo) so is not totally insane to consider a worst case scenario.

We don't have exactly a kickass theory (that's why we built the LHC in the fisrt place) and all we can talk (predict) about black holes formation is merely hypotetical.

I don't think we are in danger with this experiments other than draining taxpayers money at virtually zero ROI

We do have a kickass theory, two in fact: the standard model and general relativity. We still have a lot to learn about both (which is why we built the LHC) but to suggest that high energy particles with energies and densities many, many orders of magnitude smaller than of our sun can create a black hole (which itself is an order of magnitude too small to collapse into a black hole) requires some serious mental gymnastics falling well outside of observed physics.

Exactly, the energy of one particle is the same as how much a mosquito puts out if I remember correctly. The black holes formed from this, and this is presuming its possible to do so mind, wouldn't have enough energy to pull in other matter.

Could our theories be wrong here? Sure, but worrying about this is just like the scientists worried we would ignite our atmosphere with nuclear testing. That is, its unlikely at best and needless worry in general.

Black holes are not formed by lots of energy, but by high energy density, so your mosquito comparison is not very useful unless you've got some other measure to support it.

Not my analogy. http://press.web.cern.ch/backgrounders/safety-lhc Search for mosquito.

That's fine, but it's still not going to pacify anyone with more than a marginal understanding of how black holes work.

We have a multiparadigmatic-conflicting set of models to try to explain (parts of) the observable Universe.

If a theory can't explain nor predict origin of Black Holes, Dark Matter and say what Gravity actually is and why happens, then that doesn't qualify as Kickass in my book.

Show me teleportation and controllable antigravity and we can talk kickass again.

Did some people theorize that testing a nuclear weapon could cause the entire atmosphere of the earth to ignite?

Yes, at one point Edward Teller ("father of the H-Bomb") thought that thermonuclear weapons might set off a self-sustaining fusion reaction in the atmospheric nitrogen.

I only know about this because as a kid I read a lot of pre-space-age sci-fi, and there was a story either by Heinlein or Asimov where the solution to this "danger" was to put nuclear fusion plants in orbit.

The magic search term for this is "Konopinski report".

That gives you, a.o. https://fas.org/sgp/othergov/doe/lanl/docs1/00329010.pdf

Safety factor to get some nitrogen ignition is a worrying 1.5 when using fusion bombs of a thousand cubic meters, but even then, the reaction will fizzle out (at least, that's what I get from the abstract)

No one ever made those comments seriously. This is similar to the "atomic bombs will ignite the atmosphere" comments that are misquoted.

A scientist makes a fanciful comment in jest and the media just runs with it. There's nothing to be concerned with going on at CERN. We can't even come close to the energies nature produces every day.

This reminds me of one of my favourite Google doodles ever:


It is just you.

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