CERN's Large Hadron Collider news...

[Mike]

I find myself floating in complete darkness with no sense of falling, no sound, no wind or anything. Strangely, despite it being completely dark I can look down and see myself as if I was lit by an invisible light source. It is strangely peaceful.

[Mac]

I wonder how silly those people feel now, considering they predicted the end of the world.
when the LHC was switched on.

As if the world would suddenly e...

[Fay]

I think there is a month to go yet, when the beams are due to crash on their collision course!!!

I could do with a drop of what you were drinking, Mike!

[Mike]

I have just woke up in a dark alleyway covered in what i can only presume is 'ectoplasm'. I must have been abducted by aliens!

[Mike]

I think there is a month to go yet, when the beams are due to crash on their collision course!!!

I thought they did that this morning?

[Mac]

I think there is a month to go yet, when the beams are due to crash on their collision course!!!

I thought they did that this morning?

looks like today was just a full power run,

to see if their steering was ok.

http://press.web.cern.ch/press/PressReleases/Releases2008/PR08.08E.html

[Mike]

Yeah, it was. Though they intend to try out some 'low power' collisions in the next few days to allow them to calibrate the equipment apparently.

[Mac]

Talking about the energies involved, with these colissions,

i remember finding this article ages ago about an energetic particle that was detected.

http://www.fourmilab.ch/documents/ohmygodpart.html/

Makes this experiment very tame. by comparison.

[MarkS]

BBC4 Sat 19:30 Lost horizons. The Big Bang (
BBC4 sat 20:30 The big bang machine. (all about the LHC)

Watched both last night on iPlayer - good programmes.  I still have problems understanding string theory, though.

[MarkS]

There's a video clip here http://www.timesonline.co.uk/tol/news/uk/science/article4727892.ece of yesterday morning's trial run (after the Jersey advert) - it made me laugh out loud!!

Commentator:  "What do they do with this collider after today's events are over. Do they mothball it?"   

[JohnP]

Mark,

Yep the iplay is brilliant - I must admit BBC has been airing some excellent science related documentaries recently & it's great to be able to catch up on them all...

You are not alone when it comes to string theory... I haven't got a clue...

John

[Ian]

There's a big section on the bbc news website but I thought I stick an excerpt up here.

I remember now who Professor Brian Cox is. He did an excellent Horizon about 6 months ago about gravity. This is his answer to the question of safety at LHC.

Q: Safety Concerns

Cern have been confident in the prediction that there are no major risks associated with the LHC's operation. How robust is this prediction? In particular, how reliant is it upon unsupported theoretical assumptions? (Chris)

Okay, so how do we know this thing won't make planet Earth implode then? (Stephen)

A: Let me answer all of these at once.

The LHC has absolutely no chance of destroying anything bigger than a few protons, let alone the Earth. This is not based on theoretical assumptions.

It is, of course, essential that all scientific research at the frontiers of knowledge, from genetics to particle physics, is subjected to the most rigorous scrutiny to ensure that our voyages into the unknown do not result in unforeseen, perhaps dangerous outcomes.

Cern, and indeed all research establishments, do this routinely and to the satisfaction of their host governments. In the case of the LHC, a report in plain English is available here:

http://public.web.cern.ch/public/en/LHC/Safety-en.html

For the record, the LHC collides particles together at energies far below those naturally occurring in many places in the Universe, including the upper atmosphere of our planet every second of every day.

If the LHC can produce micro black holes, for example, then nature is doing it right now by smashing ultra-high energy cosmic ray particles into the Earth directly above our heads with no discernable consequences.

The overwhelmingly most likely explanation for our continued existence in the face of this potentially prolific production of black holes is that they aren't produced at all because there are either no extra dimensions in the Universe, or they aren't set up right for us to see them.

If black holes are being produced, then next on the list of explanations for our continued existence is the broad theoretical consensus that sub-atomic black holes should fizzle back into the Universe very quickly, billionths of a second after they are created in a little flash of particles via a process known as Hawking radiation.

In other words, they evaporate away very quickly indeed. This process, which is perhaps Steven Hawking's greatest contribution to theoretical physics, is on significantly firmer theoretical ground than the extra dimensions theories required to create the little black holes in the first place.

Even if Hawking is wrong, and therefore much of our understanding of modern physics is also wrong, the little black holes would be so tiny that they would rarely come close enough to a particle of matter in the Earth to eat it and grow.

And even if you don't buy any of this, then you can still relax in the knowledge that we have no evidence anywhere in the Universe of a little black hole eating anything - not just Earth but the Sun and planets and every star we can see in the sky, including the immensely dense neutron stars and white dwarfs, remnants of ancient Suns that populate the sky in their millions and which because of their density would make great black hole food.

So - the only theoretical bit is in the proposition that you can make little black holes in the first place. From then on, observation tells us that these things either (a) don't exist - the most likely explanation; or (b) exist, but do not eat neutron stars and are therefore harmless, probably because they evaporate away very quickly indeed!

I am in fact immensely irritated by the conspiracy theorists who spread this nonsense around and try to scare people. This non-story is symptomatic of a larger mistrust in science, particularly in the US, which includes intelligent design amongst other things.

The only serious issue is why so many people who don't have the time or inclination to discover for themselves why this stuff is total crap have to be exposed to the opinions of these half-wits. (BC)

[Mac]

You are not alone when it comes to string theory... I haven't got a clue...

http://www.superstringtheory.com/

[Mike]

This guy - http://mkaku.org/ - has some great books out that explain string theory in (almost) layman's terms.

[Mike]

There are some cool live webcams inside CERN that let you see live images. They are not very exciting but check it out...

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