Tag: physics

The Great On-Turning

Tomorrow is the Day of the Great On-Turning – not of Deep Thought, but the Large Hadron Collider (LHC). It’s the sort of thing Stephen Hawking – who I can only hope will be there – once lamented not having in A Brief History of Time; twenty years ago he never dreamed the money would ever be available to build a machine this big and powerful. But here it is!

No doubt you’ve heard of this device from many other sources, not least Andrew Denton’s interview with Brian Cox on last night’s Enough Rope. Like most discussions of the Collider, that interview featured heavily the claims that the LHC will destroy the world, mostly fuelled by the ridiculous law suit still pending in the District Court of Hawaii (filed by a group of “concerned citizens”, at least one of whom has previously tried to stop other large particle collider projects). Well, we’ll have none of that here; if you’re still concerned by the warnings of crackpots, let CERN reassure you with their latest press release on the matter.

Instead, here’s a primer for those of you who are still unsure what it’s all about. First, let’s break down the name:

  • Large – the Large Hadron Collider is a “large collider of hadrons”, not a “collider of large hadrons” (hadrons do come in different types – see below – but not significantly different sizes). Some sources claim it’s the largest machine ever built by humans, and it’s certainly the largest science experiment – it’s a 27 kilometre long loop, buried underground near CERN in Geneva, and it crossed the border between Switzerland and France. It took 10 years to build with another 10 years of design work before that.
  • Hadron – a hadron is a particle made up of quarks, one of the fundamental particles that make up all matter. The most famous hadrons are baryons, which consist of three quarks, one of each “colour” – red, green and blue – that are held together by the strong nuclear force. Baryons include neutrons and protons, which make up the nuclei of atoms. The difference in charge between positively charged protons and neutrally charged neutrons is down to basic maths – different “flavours” of quark have different charges (it’s a little more complex than that, but we’re only interested in the quarks that make up “normal” baryons). In a neutron, the positive charge of one up quark (+2/3) is exactly balanced by the negative charge of two down quarks (2 x -1/3); in a proton, there are two up quarks (2 x 2/3) and one down quark (-1/3), resulting in a total charge of +1.
  • Collider – the LHC is a particle accelerator – it accelerates particles to very high velocities, giving them enormous energies. It’s also an “atom-smasher” (though it’s only smashing bits of atoms, not whole ones) – its purpose is to accelerate particles in two directions, colliding them together. It was collisions like this that allowed us to observe the existence of quarks, since normally they can’t exist on their own; smash some hadrons together, though, and their component bits go flying all around the place like bits of plastic bumper in a car crash.

The specific purpose of the LHC is to accelerate hadrons to speeds which will give them enough energy to simulate the state of matter only a few billionths of a second after the Big Bang, when things were very different to how they are now. This is hugely exciting because so little is known about the origins and initial formation of matter, or as Brian Cox put it, “what makes stuff stuff”.

One big question is to do with photons and W and Z bosons. A great success in particle physics was a combined theory explaining both the electromagnetic force and the weak nuclear force; it basically says they are two different aspects of the same force, which at high energies – like in the Big Bang – would manifest as a single “electroweak” force. The particles that carry these forces – photons and W and Z bosons, respectively – are different forms or states of the same particle, and at suitably high energies the combined force is carried by the Higgs boson. One of the big mysteries is why photons have no mass, while the W and Z bosons are massive (meaning they have mass, not that they’re huge!); hopefully observing the Higgs boson will shed some light on this!

It’ll be more than a month before the first collision is made – tomorrow’s “Great On-Turning” will involve only a single beam, not colliding with anything. But it’s an exciting time to be a scientist, or even a scientician – some big questions are going to get some kind of answer very soon. Of course, once the “answer” is determined, the real fun begins: trying to interpret what it all means… Perhaps it’s not so far from Deep Thought, after all.

That sensation you’re feeling is the Quickening

Man in the Lab Coat reader and friend Dan posed a great question in the comments of my last post: assuming an astronaut was immortal, would they experience an infinite amount of time while falling into a black hole?

The tricky part about this is time dilation. To an outside observer, once the astronaut passes beyond the event horizon she can no longer be observed, and theoretically takes an infinite amount of time to fall in – we’ll never hear from her again. But for the astronaut herself, time proceeds as normal – and it takes her a finite amount of time to fall into the black hole, or at least, to fall far enough past the event horizon that she is spaghettified. I also pointed out that no form of immortality save being unaffected by gravity could save you from this fate – and if you were unaffected by gravity, you wouldn’t be falling in in the first place! So the answer is no.

Note, too, that this whole scenario is only feasible if it’s a supermassive black hole – for smaller black holes, an astronaut would be spaghettified long before crossing the event horizon.

While checking my facts, I came across a fascinating idea – that it’s possible to find a “sweet spot” of acceleration that maximises that finite time before you are destroyed. This study can be found in a paper from last year titled “No Way Back: Maximizing survival time below the Schwarzschild event horizon“, written by two Australian physicists, Geraint F. Lewis and Juliana Kwan from the University of Sydney. A great summary of the article can be found in the Universe Today blog.

The Man returns for National Science Week!

Ben McKenzie, the Man in the Lab Coat, makes two appearances in August for National Science Week!

First, he returns to Melbourne Museum for Not the Nobel Prize on Friday, August 22. Following on from last year’s hit show, Ben will join fellow a panel of fellow comedians as they pit their wits against actual scientists to sort science fact from science fiction.

And, from August 22 to 24, Ben launches a new show, A Brief History of A Brief History of Time, at the Royal Society of Victoria. He’ll prove you don’t need 12 degrees to understand Stephen Hawking’s great unread classic, A Brief History of Time.

Check out the show page for more details, and visit the National Science Week web site to see what else is happening in Melbourne and all round Australia.

The Mr Al & Mr Nick Christmas Special

Come to this fundraiser and help Ben’s friends Mr. Al and Mr. Nick get to the Adelaide Fringe next year, where they will once again share a venue with the Man in the Lab Coat.

Even if you don’t give two figs for Mr. Al and Mr. Nick, come see the Man in the Lab Coat audaciously attempt to summarize A Brief History of Time in under 15 minutes! Plus I won’t be the only one performing; you can also see such local comedy luminaries as Lawrence Leung, Andrew McClelland, Courtney Hocking, Scott Pollard, Jess Moir and, of course, Mr. Al and Mr. Nick.

When: Thursday 15th December
Where: Upstairs at Vibe On Smith, 123 Smith Street, Collingwood
Doors: 7:30pm Show: 8pm
Cost: $10